#AskGCNTech I’m looking to buy my first road bike, and I’m leaning towards a second-hand option. How worried should I be about frame material fatigue? Will there be a difference between aluminium and carbon?
Oisin Feeney yeah, that’s why I’m torn. I can get a decent (or very decent) second-hand carbon bike (supersix evo hi-mod) for roughly the money of a new alu specialized allez elite). And I can swap components later on, but the frame would be here to stay, so I’d like to be relatively certain that it’s going to last.
I'm actually using a mishmash of shifting components right now on my gravelbike. The baseline is a Tiagra 4700 groupset with a 34T cassette but I replaced the front derailleur with a 105 RD-R7000. I also replaced the Tiagra crankset with a Shimano FC-CX50 46/36 10speed Crankset and changed the small chainring to a 34T. And to round things out I changed the 10speed chain with an 11speed chain so that it'll fit the 105 derailleur a bit better. No issues at all - it's the smoothest shifting you can imagine. So, I'd go right ahead and just try a tiagra crankset.
Or you just get 105 FC-R7000 50/34 crankset - that's 11speed compatible without any issues. The chainrings might even fit the ultegra crank but no garantees there.
_@Oneris Rico_ -- I switched to a short crank on my road bike four years ago and like it very much. Formerly, I used a 175 mm, but now I use 165 mm. The reason: It reduces my knee height at the top of the pedal stroke which reduces knee and hip stress. (Since the crank arm length equal's the radius of the pedal circle, a reduction of 10 mm from each crank arm translates to a 20 mm reduction in pedal circle diameter. So my knee rises 20 mm less with 165 mm crank arms compared to 175 mm crank arms.) For long endurance road rides, I rarely feel any knee discomfort with a short crank. With the 175 mm crank arms, I would begin to feel knee strain by 100 miles (161 km). Another factor is age. As you get older, you'll discover that a shorter crank arm length is more comfortable. Regarding perceived effort, in my experience there is very little difference unless you make a radical change in crank arm length. This doesn't happen because the range of crank lengths offered by road crank manufacturers isn't that big. I have bikes with both 165 and 175 mm crank arms and I don't perceive a difference in effort, so I don't think leverage of the crank arm gives a complete picture. Since you're moving your legs less around a smaller pedal circle with a shorter crank (assuming the same cadence), you may pick up some benefits to the leverage of your legs which offsets (I think) the small reduction in leverage of the crank arm, itself. And you're also moving the mass of your legs a little less. Therefore a small reduction in leverage of the crank arm, itself, may be offset by increased bio-mechanical leverage of the legs and hips, etc. I've been using a power meter for years and a 10 mm difference in crank length does not appear to effect my power as long as I'm properly fit to my bike. The bottom line for me is: (1) I find that it's easier to hold a higher cadence with a shorter crank, which helps me sustain a higher power and higher overall speed. (2) I have less knee strain on long rides. Unfortunately, short cranks are not very common for road bikes -- especially if you need very short cranks. For example, my wife is short and she uses 145 mm crank arms. They simply are not available in road groupsets. So she gets her cranks from the BMX market where there are plenty of short crank models. Here's another idea: If you make the switch to a short crank on your road bike and you like it, another thing you can do to hold a higher power on hills and reduce your knee strain even further is to switch to oval chainrings. I've been using a 52t Rotor QX1 Aero 1x chainring on my road bike and like it very much. It's one of the few oval chainrings that you can adjust the angle of the wide part to match the most efficient part of your stroke (this position changes from TT to road because of your body position). However, ovals are not for everyone -- they definitely do not shift as well in a 2x setup. Plus, I notice little benefit on flat roads or down hills -- ovals help me mostly on hill climbs.
D.Eldon thank you so much for this very detailed answer, I'd consider it even more after you mentioned your wife, I'm not a tall person myself 😅... The reason why I was trying a bigger crank is because my short one bent, so I was waiting for a replacement but my bike shop told me they only have a 5mm longer than the one I had, o doubt it'll be noticeable, what do you think?
Oneris Rico 5mm can be nothing or it can destroy your pedal stroke. It depends on how close to your limit you are. Don’t think of crank length like tire pressure, where there is an “optimal” value. Think of it like saddle height, where things are OK below a certain value and get very ugly suddenly above that value.
You mention that there is no noticeable difference in power using a short crank over a long crank. Since power is a factor of torque and cadence, it would only be possible to record the power result, not the effect on torque. I note that you mention gearing and cadence factors, but unless you have a laboratory test, there are too many other external factors that will impact on test results. There is a difference in torque using shorter cranks, and it really does depend on an individual's position on the bike, flexibility and physiology as to which is better for them and which allows them to put the most usable power to the road.
@Oneris Rico, FWIW, I'm 5'11, and I ride 165 cranks. I'm olderish, and I prefer to spin vs. mash, the short cranks are smoother at high cadences. Also I get my power at higher cadences (I'm more like horsepower vs. torque), and I have plenty of cardio to tap, so it doesn't bother me to be spinning faster. The reduction in hip and knee angle makes a world of difference over long rides as far as how I feel when I get off the bike and the next day. I don't use oval chainrings, as I found them to bother my knees, but instead ride with a wide range rear cassette. (11-36+). The gear gaps don't bother me as I am comfortable spinning at many cadences, I'm happy anywhere from 80-130 rpms, but I prefer to be in the 90-120 range. For hills I just get into that big gear and spin up the hill at a much higher cadence then most other people I ride with are on their smaller cassettes. My knees very much prefer this, vs. grinding up the hill. I'd actually consider 160 or even 155 cranks perhaps, but they are hard to find for road group sets.
I've got long legs 78.5 cm (BB to saddle) but I chose to use short 165 mm cranks, I managed to cure the knee pain I suffered from thanks to the smaller leg articulation. It is recommended to reduce the amount of teeth on your chainrings to make up for the smaller lever force, I have 50-36T.
i was going to say some normal silicone calk either clear or some are in colors that may look a littler better. and it can be removed easy as well. i assume that is what you mean by putty but yeah seems like the obvious choice.
@@bretmohler9719 this has worked for me in the past. I built up a Propel SL from scratch with UltegraDi2 and there were a few grommets that weren't quite the right size. A little bit of silicon did the trick
Bryan Oliver you have it almost correct “you can spin faster...with shorter cranks” more accurately “you must spin faster...with shorter cranks”. It is all a matter of physics, shorter cranks require more foot force to deliver the same force through the chain, because this additional foot force “feels” harder riders typically change to a smaller gear (and travel proportionally slower), if you do spin faster you can get back to the equivalent speed of longer cranks but typically riders will stay slower and make the observation that they are riding “easier”, of course you are, you are riding slower. You get nothing for nothing, there is no mysterious extra force the suddenly appears with shorter, or longer cranks...all the best.
Using longer cranks not only closes down the hip angle, it also tightens the knee angle. It has the same effect of reducing saddle height. If you swapped from 170 to 172.5 you would have to drop saddle by 2.5mm to maintain same knee bend. Then at the top of the stroke your knee is coming up an extra 2.5mm thus giving the effect of dropping saddle by 5mm therefore increasing load on knees.
With regards to different pedal standards, Shimano made their Dyna-Drive pedals and cranks, which used a 1" thread. The idea behind them was three-fold: offer an aerodynamic advantage by allowing a lower saddle height, create a more stable footbed, and give more cornering clearance due to the low-profile pedal body. I have them on my Dura Ace AX aero bike. It was also offered on the 600 AX groupset, and in a different design on the Deore touring groupset.
I moved from 172.5 cranks to 165 cranks, and I was able to generate 20 more watts at the same HR the day after I got switched onto the shorter cranks. It makes a huge difference as your muscles are closer to their optimal length to generate power, and your foot doesn't have to travel as far to do the same cadence so you don't have to move your legs as fast to cover the further distance with the longer cranks. I would say it is something that can really increase performance once you adapt to it. I highly recommend it.
Joe Blommel jeez. I’ve been trying to convince my 5’ 5” friend (really short legs. He basically cannot ride a 50cm trek emonda because its seatmast doesn’t go low enough) to go with 160mm cranks but he has been gaslighted so hard that he truly thinks that if he went with 160mm, he would lose all sorts of power. It’s very sad to watch him struggle to pedal with 170s, because he will sit very upright, even in the drops, and flare his knees out to make room. I wish he could see all these people (including me) who have gone to shorter cranks and gained power.
@@404nobrakes I've got a longer torso and shorter legs for my height, and the longer crank arm thing is old school thinking about one aspect of a larger picture. The best answer i've learned is that this is a big "it depends" answer for what someone is trying to do.
love my 150mm cranks on the roadbike. My utility/travel bike has 152.5mm cranks that were cut and drilled from 175mm cranks, it had long flat section to allow new hole
I had a cheap so-called mountain bike in the 90s with 28/38/48 chainrings attached to 1-piece 165mm cranks & a 28-14 5-speed cluster. I rarely used the 28t chainring & was tired of running out of gears at the top end. So I swapped the crank out for a 115mm & trained myself to pedal at about 140rpm to maintain linear speed of the pedals. It took a few weeks to get used to it but it was great being able to go faster than 50 km/hr without spinning out.
Back in the day it was all about length....175 or longer....a few years ago I put 165s on my road bike and they are great......easier to spin at high cadence and much gentler on the knees
I switched from 175 to 180 on my road bike, and they are great. I have no problem maintaining nearly the same cadence as before, and less force needed for the same power, so gentler on the knees (in my case, anyway). It should be more about riding the correct length that feels good to you than "shorter is better" or "longer is better". We've all got an ideal length and it's generally going to be at least loosely based on your leg (specifically femur) length. I can spin the 165mm on my track bike, too, but I can definitely feel that they're much too short for me.
got short legs (typical hungarian)- too often w/stock cranks (175 & 170 ) I felt I needed to adjust my position seat felt too low/too high, fore/aft - a bit frustrating to be honest- then, I tried 165s and felt dialed right in- hilly centuries /urban commutes. everything just works feels right from start to finish. the final sprint home even after a long ride gets the hr peaking max- double plus good, you know ? if you got issues like I did, it is worth the investment to try - the payoff will make you wish you tried sooner
172.5mm to 160mm cranks here and the difference is amazing. I can get more aero, stay aero longer and have more power in an aero position thanks to the shorter cranks opening up my hip angle a few degrees.
I agree with Ollie, have never had any issues with a double chainring up front. Have logged 40,000 miles in the past 5 years including 10,000 on gravel, have never once adjusted or dealt with any issue with the front derailleur on any of my bikes.
In regards to the disc rub - sometimes the actual mount can become warped (or be warped right from the get-go), in which case you might need to get the mount re-faced. You can attempt this yourself, Park makes a tool for this, but unless you are very comfortable with doing this kind of thing (and have the cash to buy a tool you might use once or twice), take it to a shop and have them do it. You can also try visually re-centering the caliper. I tried the centering tricks from GCN on my rear caliper many times to no avail, then I grabbed a flashlight so I could see where the pads were sitting and just did it by eye, and I haven't had a problem with rub since.
Should you ride shorter cranks? No. What you should do is test various crank lenghts. My local shop had a power meter hooked up to a fit bike. I tested 175, 177.5, and 180 length cranks. The test was holding a harder pace for 5 minutes. Then look at what the heart rate was. 177.5s lowered my hearrate (for the same output/time) by 10% over 175s. 180 was only 5% better thann 175. Unfortunately no-one makes 177.5 anymore. So all my bikes have 180 (the next best thing). Oh, my inseam is 38 inches. Get the test done, find out what works best for your leg lenght and spin style. (The best way to cofirm results would be to do the test 3-ish times over a period of several weeks. It's also best to do the test mid season when your legs are in the zone - i.e. not at the end of the season when your legs are toast, not at the beginning of the season when you're legs aren't up to speed yet).
I've recently upgraded from 175 to 200 mm cranks on my mountainbike. Should have done this years ago. The amount of torque I can put out now is enormous. I am 2 metres 6, inseam is 104 cm. crancks should be 10% of you length, or 20% of your inseam.
@@LordLlurch please do explain how you came to the conclusion that "cranks should be 10% of you length, or 20% of inseam." I'm 182cm tall which would mean I need a 368mm according to you doofus.
Agree. I use a 105 7000 chainset (165mm by the way!), with a Sora 3000 9 speed gearset and 9 speed chain. Runs fine. Bigger issue to me seems going for a 34 inner ring rather than a 36 will give a negligible reduction in gearing (less than the you would achieve with a one tooth bigger rear sprocket). Is it really worth the effort?
For the guy that wanted grommets or plugs for his carbon frame holes he's no longer going to need, try a bit of plumber's putty. You can dye it (within reason), it's waterproof and, if you get sick of it, you can scoop it out with a dental pick and wipe it right off.
I'm 1.70 with an 52 frame size, I used to ride 175mm cranks, and changed to 170mm, the difference is huge and, personally, I feel like a I do less effort now than with the longer cranks
You are correct Daniel shorter cranks transfer less force through the chain and apply less force to the cassette, or in other words less effort. If you want to go the same speed as you did with the 175mm cranks, however, you will need to produce proportionally more foot force with shorter cranks (a.k.a.more effort)
@@kiwisteve408 Yes, I noticed that when doing time trials, however IMHO, a 53/39 × 11/28 should go with 170mm cranks, and a 52/36 × 11/28 should go with 172mm or, if you're a big rider, 175mm. Nonetheless, you always can do strength exercises and training to compensate the effort needed.
@@xxzmk definitely go for it. I'm 5'7 and switched from 172,5 to 165 cranks this year and it felt great. I can't tell much about the actual power output but my pedal stroke feels much smoother now and I'm able to maintain a higher cadence (especially when riding in the drops). No negative side effects at all.
@@endianAphones I'm also the same height and used 165 on all my bikes for many years and never looked back. I have a new 170mm takeoff for sale if you're interested, but I recommend 165.
remember that with shorter cranks you will need to raise your saddle. A smaller crank will describe a smaller circle (pi x d) so your cadence will rise slightly. Wiggins used 170mm on his road bikes and he is over 6'
A really cheap hole plug are foam ear plugs. Squish, insert, let expand, trim to length and paint to match specific frame area where they'll be installed.
For the Canyon frame: You can use Sugru. It's moldable glue that you can use to fill the hole and even paint it to match. When / if you want to remove it you can just pick it out and it will come out in one or two pieces. Dry its more like rubber than a silcone sealant making it really easy to live with.
Aisaku Pradhan Or a thought I had was clear silicone sealant that a plumber would use - easy and transparent way to fill a small hole. About £3 a tube from a DIY shop.
You could fill the holes with caulking and holes will be waterproof. There are many colors to choose from so you could probably find a color close to what you need.
Yes, short cranks are ideal if you have limited gears, or on rollers, where force has negligible affect on speed compared with rpm. However as soon as you need force to climb for example or ride a bigger gear the torque of the longer cranks will produce more speed for the same foot force.
In regard to the recommendations for the user looking to swap the 10 speed crank on an 11 speed system, I wanted to add additional points that were omitted in the video. 1. Don't put a 10 speed crank on an 11 speed system, since the chainrings are thicker and spaced further apart, the chain has a far higher likelihood of getting stuck between them, which is the main reason not to do it. 2. If you are up-sizing your cassette as recommended in the video, you will also likely need to install a new chain, or additional chain links, as additional links will be needed to take up the additional chain wrap required by the larger cassette. If you don't do this, it can bind the chain and prematurely wear on the rear derailleur when in less favorable big-big chainring/cassette gear combinations.
*Knee Pain FYI:* Shorter cranks (150-165mm) are often used with recumbents due to the rider being very fixed in position (i.e. no shifting/standing) and the not uncommon consequent knee pain that "regular" length cranks cause. For uprights, apart from the usual seat and pedal positioning solutions, this _MAY_ be worth a try.
And Mickie Freiburg used SUPER long crank arms when he became a track cycling world champ, as this suited HIM at that time. We're all a bit weird and different from each other, so if one has the possibility try something new/different - go ahead!
@07:36 no it's not a *requirement* for disc brake either - many (older) bikes (mind included) with disc brakes work just fine with QR. I suspect most rim brake bike hold-outs are after wheel changing speed and that's the reason.
Ollie, I feel bad that you didn't get to go to your home county to look at the World Championship bike tech, but glad that you made us a video. If this keeps up, I'm just going to assume that you're the regular Tech Clinic presenter and Jon is a temp worker.
On different bikes I had 172.5 cranks and 165. And while I think I could get used to one or the other given enough time, the most disruptive thing is just moving from bike to bike. I felt most comfy naturally at 165 so I went to 165 on both.
I gave up on the front derailleur. We have 9 bikes in our household. Started the year with 5 front derailleurs. We’re down to 3. Goal is to go down to 1 front derailleur and 8 1by systems. The 1 front derailleur we’re keeping is DI2, thus worth riding. Everything else will go.
Shorter crank arms allow for more ballistic pedal movement, in turn (no pun intended) allowing the rider to turn over the pedals faster. You can improve power much more training and experimenting with gear ratios then having a longer crank.
Great video, but Oli made one mistake when talking about pedal threads. A left-hand thread on the left pedal will actually cause the pedal to loosen with the forwards pedalling motion. Pedal threads where designed like this when bearings were a little less reliable; so when your pedal seizes up, it'll simply come loose rather than snapping your ankle.
39in inseam & run 180mm, and want longer. Getting sick of people telling me that short legs need short cranks, Average legs need average cranks, long legs need average cranks. I didn't notice too much of a performance difference either way, but with the longer cranks my knees feel better after hard riding.
Ollie mentions that with different crank lengths, altered torque doesn’t matter much because you can simply change gears. But isn’t it so that with a longer (crank) arm, you generate more torque with the same pedal force? Torque = force x arm. So changing gears is another matter? Of course, this is apart from the whole biomechanical issue, but still.
Chainrings on Shimano, despite being the 110 distance, are not universally interchangeable: They have grooves and ridges that won't match those on the ends. You'd need to file a bit. I for one recommend getting a Specialites TA set. As long as the minimum teeth distance of 12 is maintained, you can use any combination!
For recumbents, so many people opt for shorter cranks as it makes people just spin and more comfortable for the hips and knees. I think many are 165 and 155
Longer or shorter cranks? Let's look at this like we would decide what size of chainrings to equip. After all, the pedals are going around in circles, correct? In terms of efficiency, it takes more effort/energy to turn a 53 tooth chainring than a 50 tooth compact chainring. It easier to turn the small ring, thus less energy. A smaller crank will then be easier to spin around because its radius is shorter and is able to travel faster around its circumference, so you can maintain a high cadence longer.
Shorter cranks don't mean less torque at all. If we rode by just hanging a weight off the pedal then that might be true. But we ride by pushing the pedal with our foot, which is attached to our lower leg, which is attached to our upper leg, which is attached to our torso. It's all a system of levers at different angles, powered by muscles that have to contract, the performance of which is related to how far and fast they have to move, and ultimately limited (in anything other than a sprint) by your aerobic capacity. Even if you could argue that shorter cranks might have less torque, the counter argument is that you can spin a higher cadence for the same pedal force and pedal speed, meaning power is unaffected.
Matthew King But cycling at a higher cadence than that which you are accustomed to is not so easy... whilst a longer crank arm gives you the same torque with less pedal force. Irrespective of where that force is coming from exactly.
The experience of recumbent riders is very relevant here. Many ride truly short cranks 130 not being uncommon, I use 143 the odd number being due to having long hollow cranks cut down. Always the same experience is that it takes 1000km or so for your legs to get used to it, many reports of tests on crank length are based on measuring the performance difference before the legs have relearnt the muscle memory. If you want to try shorter cranks then give it plenty of time before rushing to a judgement.
Colin Rose Perhaps recumbent cyclists need shorter cranks because gravity and maybe even biomechanics is against them, thus they are unable to generate the force required to turn longer cranks around?
Lars Borghouts my post was about giving yourself time to get used to shorter cranks, I ride an upright and a recumbent and power output is identical for me, albeit the recumbent is faster for a given power output.
Park Tools should develop a disc rotor press. they could machine various tolerance molds to place a bent rotor in, apply just the right amount of heat, then cooling the metal rapidly to harden it again. like a George Forman grill for brake rotors. or am i just high?
That was a strange request on the last question. I have no problems with my front derailer, it works perfectly fine. Admittedly having di2 makes changing gears easier but even with mechanical gears I have not had any problems.
Before replacing the calipers: Sometimes when you take your wheel out of the frame, there's always a joker that presses the brake lever, maybe that happened to you.. Remove the wheel and brakepads and with an 8 or 6mm allen ball wrench, carefully push the pistons back inside. Reinstall everything, reposition your caliper as shown in the video, brake a couple of times and test it again.
i'd honestly like to find a set of 185mm or 190mm cranks, i've got long legs and they don't like high rpm's trying to top out speed. course i only have a 21 speed mountain bike at the moment but can hit ~25mph flat out but just can't pedal at that speed for long because my legs don't like the short throw. you could say i'm a bit more like a diesel with a long torquey throw as opposed to a shorter higher rpm output. maybe someday i'll get the $ saved up for a good road bike and can get a nice group set that'll work better for me. my longest trek with my current bike atm is ~40 miles one way before my left hip gave out and i needed a lift back home.
Technically, your foot speed is greater for the same RPM on a longer crank than a shorter crank. I have found that at high cadence, a shorter crank results in less saddle bounce. Re your analogy of a motor, a diesel motor is more like a short crank, and a high reving motor more like a long crank. Longer cranks are way more aggressive on your hips and knees.
#ASKGCNTech Thank you for such a great show. One of the highlights of my day. I have a Canyon Aeroad that came with regular bar and stem. Looking for a 1 1/2" integrated carbon bar system and striking out. I live in the USA and Canyon does not ship here currently. Need help! Any recommendations?
#AskGCNTech Can you tell us something about experiments with non-standard wheel sizes in road cycling (other than 700C and 650C)? Even UCI allows wheels to be anywhere between 55 and 70 cm in diameter so someone must have tested it. Any experience with 'mullet' road bikes maybe? Tyre widths have increased a lot recently - why isn't anyone talking about the wheel size? I can see a potential for a whole video in this topic ;-)
tiagra cranks work just fine, the spacing difference is practically nothing. The same for mixing 5800/5800/9000 and 7000/8000/9100 cranks and FD, a half millimeter difference is nothing. The real question is why bother, 34/36 is only a 5 rpm difference in gearing. The cassette is more of where you should look, 32 or 34 in the back.
You are NOT going to be able to recruit your muscles in a greater range of motion on a shorter cranks - quite the opposite, they are going to be recruited in a smaller range of motion. However, you ARE going to be able to recruit your muscles in a more efficient range of motion.🤓
Interesting how short cranks are now better for hip angle when for decades short people were told they'd get used to the same length someone five foot ten would be comfortable on.
Here we go with the disc brake hate...... it's getting old! ...... and you're wrong! Rim brakes, like disc brakes, aren't perfect...... they have inherent problems too!
Another perspective with short cranks - short story they didn't work for me, mostly from a dislike of how they felt when standing.. I'm 1.87 m and long legs (1035 mm from pedals to saddle). Normally use 175s in all disciplines (road, TT, CX, MTB). I use short cranks extensively during certain periods of the year - winter fixed gear commuter has track cranks, 165. No issues there, very small gear for pedaling through snow (46x 19-21) The short cranks feel a bit heavier to push, but quicker to turn (less torque issue). Not a big deal, you adjust in the gears and move on - they had no effect on threshold power, but did decrease maximum power either seated or standing. What I found was a deal breaker was standing up on the pedals; the tiny circles allow for very little leverage either for climbing or sprinting - and yeah, I could pedal faster but I already can hold 200 + rpms for about 20 s (I used to win the local roller races). I also didn't feel difference on TTs either, never felt impeded in hip angle, I'm flexible enough that my main issue on the aero position is not hip/back issues, it's vision - my head is too low and have to crank my neck too much. If you have tighter hips/glutes then they may work for you. One additional factor - I use my pedals way back on the foot; not quite mid-foot position but as far back as a speedplay extender will allow. Maybe that could be a factor as well.
Rod Diaz holy cow. 1035mm?? You’ve got some stilts. I would say you definitely went past the threshold of “shorter” and went to “absurdly short”. My saddle height is 760mm - 275mm shorter than yours - and I find 165mm cranks to be adequately short. I could probably go 167.5 too. If it matters, I am 170cm. I have a friend who is 165cm and has much shorter legs. He’s using 170s and is reluctant to try 160s.
Rod Diaz also, the main issue with standing on shorter cranks is that your cadence has a much harder cap. Spinning up 10-20rpm faster to achieve the same power is easy-ish when seated. When you’re doing a balls-to-the wall sprint at 100rpm, it’s not so easy.
@@404nobrakes yeah, I found that unpleasant - I naturally don't like spinning when standing and prefer 80-85 rpm when off the saddle. Even full sprints I prefer (and have better power readings) at 100-105 rpm than using a smaller gear. This is also probably related to the very long legs!
#AskGCNTech Hi, love the show! I'm looking in getting a CX bike, but I'm on a budget. So I'm looking in making a CX bike which I can use as a road bike as well. Would I be able to fit a 2x chainring on a sram 1x setup? And what other things should I know about? Thanks!
Thanks Ollie. I watched this just after I got out the shower, glistening, dripping moist with the dew of anticipation. I didn't even have the water on.
#AskGCNTech I am wondering if it is possible to have a crankset with a 52/34. I currently have a 50/34 and I feel like I could go faster on the flat, but I don't think I can go back to the 36 as the smaller ring. Is the gap too much, or it could make it work?
#AskGCNTech I've been wondering something pretty specific for a while. Can I convert my cyclocross/gravel bike to a passenger bike if i want to? what would I need to do for this? a rear wheel which can carry more weight? a rear rack seat? Would I be better off getting a trailer for the bike instead if I wanted to carry someone. I don't know if I'll actually do it but I really just think the idea of it is super fun. I have a Felt F65x.
How do you fix a hydraulic caliper piston that's not retracting symmetrically (at rest one piston sticks out from the cylinder far more than the other), and though the caliper is centred, one piston still rubs.
You wouldn't need to change the cassette for any reason other than to achieve the same relative gear ratios. Going significantly shorter with you cranks means that for the equivalent number of teeth front and back you'll have to produce more force for the same cadence - if you don't feel you have easy enough gearing to get over climbs with your shorter cranks then changing cassette to have a larger big cog might be a good idea
Hello Jon...what are the differences in components of Shimano tiagra and Shimano 105 that should be considered while upgrading...hope you are back...love the show...#askgcntech
#askgcntech one of my legs is almost an inch shorter and is much weaker than the other. What can I change on the bike to compensate for that? Shorter crank arm, shoe inserts, cleat spacers come to mind.
The 105 chainrings are not compatible with the R8000 crankset. I tried this about two weeks ago, and one of the Ultegra arms has a little "swoosh" that makes the 105 chain rings not fit.
Hi! I have a bike-project going on, where i mean to mix different bike-components. I understand there is different lever and travel pull-ratios across shimanos range of different groupsets. Can you make a video comparing them, and their compatability with one another? #AskGCNTech
#AskGCNTech When I let go of the handlebars I have to lean towards the right side to keep going straight. What can cause this? I have not had any crashes and have not changed anything on the bike. This has progressively been getting worse over the last year.
We love to help here at GCN Tech, so if you have a question that you'd like us to answer leave it in the comments below using #AskGCNTech
#AskGCNTech I’m looking to buy my first road bike, and I’m leaning towards a second-hand option. How worried should I be about frame material fatigue? Will there be a difference between aluminium and carbon?
Oisin Feeney yeah, that’s why I’m torn. I can get a decent (or very decent) second-hand carbon bike (supersix evo hi-mod) for roughly the money of a new alu specialized allez elite). And I can swap components later on, but the frame would be here to stay, so I’d like to be relatively certain that it’s going to last.
I'm actually using a mishmash of shifting components right now on my gravelbike. The baseline is a Tiagra 4700 groupset with a 34T cassette but I replaced the front derailleur with a 105 RD-R7000. I also replaced the Tiagra crankset with a Shimano FC-CX50 46/36 10speed Crankset and changed the small chainring to a 34T. And to round things out I changed the 10speed chain with an 11speed chain so that it'll fit the 105 derailleur a bit better. No issues at all - it's the smoothest shifting you can imagine. So, I'd go right ahead and just try a tiagra crankset.
Or you just get 105 FC-R7000 50/34 crankset - that's 11speed compatible without any issues. The chainrings might even fit the ultegra crank but no garantees there.
Thank you!!!! And btw isn't it cruel the Yorkshire guy is not at the worlds? #FreeOllie
_@Oneris Rico_ -- I switched to a short crank on my road bike four years ago and like it very much. Formerly, I used a 175 mm, but now I use 165 mm. The reason: It reduces my knee height at the top of the pedal stroke which reduces knee and hip stress. (Since the crank arm length equal's the radius of the pedal circle, a reduction of 10 mm from each crank arm translates to a 20 mm reduction in pedal circle diameter. So my knee rises 20 mm less with 165 mm crank arms compared to 175 mm crank arms.) For long endurance road rides, I rarely feel any knee discomfort with a short crank. With the 175 mm crank arms, I would begin to feel knee strain by 100 miles (161 km). Another factor is age. As you get older, you'll discover that a shorter crank arm length is more comfortable.
Regarding perceived effort, in my experience there is very little difference unless you make a radical change in crank arm length. This doesn't happen because the range of crank lengths offered by road crank manufacturers isn't that big. I have bikes with both 165 and 175 mm crank arms and I don't perceive a difference in effort, so I don't think leverage of the crank arm gives a complete picture. Since you're moving your legs less around a smaller pedal circle with a shorter crank (assuming the same cadence), you may pick up some benefits to the leverage of your legs which offsets (I think) the small reduction in leverage of the crank arm, itself. And you're also moving the mass of your legs a little less. Therefore a small reduction in leverage of the crank arm, itself, may be offset by increased bio-mechanical leverage of the legs and hips, etc. I've been using a power meter for years and a 10 mm difference in crank length does not appear to effect my power as long as I'm properly fit to my bike. The bottom line for me is: (1) I find that it's easier to hold a higher cadence with a shorter crank, which helps me sustain a higher power and higher overall speed. (2) I have less knee strain on long rides.
Unfortunately, short cranks are not very common for road bikes -- especially if you need very short cranks. For example, my wife is short and she uses 145 mm crank arms. They simply are not available in road groupsets. So she gets her cranks from the BMX market where there are plenty of short crank models.
Here's another idea: If you make the switch to a short crank on your road bike and you like it, another thing you can do to hold a higher power on hills and reduce your knee strain even further is to switch to oval chainrings. I've been using a 52t Rotor QX1 Aero 1x chainring on my road bike and like it very much. It's one of the few oval chainrings that you can adjust the angle of the wide part to match the most efficient part of your stroke (this position changes from TT to road because of your body position). However, ovals are not for everyone -- they definitely do not shift as well in a 2x setup. Plus, I notice little benefit on flat roads or down hills -- ovals help me mostly on hill climbs.
D.Eldon thank you so much for this very detailed answer, I'd consider it even more after you mentioned your wife, I'm not a tall person myself 😅... The reason why I was trying a bigger crank is because my short one bent, so I was waiting for a replacement but my bike shop told me they only have a 5mm longer than the one I had, o doubt it'll be noticeable, what do you think?
Oneris Rico 5mm can be nothing or it can destroy your pedal stroke. It depends on how close to your limit you are. Don’t think of crank length like tire pressure, where there is an “optimal” value. Think of it like saddle height, where things are OK below a certain value and get very ugly suddenly above that value.
@@404nobrakes that's a great analogy, thanks!
You mention that there is no noticeable difference in power using a short crank over a long crank. Since power is a factor of torque and cadence, it would only be possible to record the power result, not the effect on torque. I note that you mention gearing and cadence factors, but unless you have a laboratory test, there are too many other external factors that will impact on test results.
There is a difference in torque using shorter cranks, and it really does depend on an individual's position on the bike, flexibility and physiology as to which is better for them and which allows them to put the most usable power to the road.
@Oneris Rico, FWIW, I'm 5'11, and I ride 165 cranks. I'm olderish, and I prefer to spin vs. mash, the short cranks are smoother at high cadences. Also I get my power at higher cadences (I'm more like horsepower vs. torque), and I have plenty of cardio to tap, so it doesn't bother me to be spinning faster. The reduction in hip and knee angle makes a world of difference over long rides as far as how I feel when I get off the bike and the next day. I don't use oval chainrings, as I found them to bother my knees, but instead ride with a wide range rear cassette. (11-36+). The gear gaps don't bother me as I am comfortable spinning at many cadences, I'm happy anywhere from 80-130 rpms, but I prefer to be in the 90-120 range. For hills I just get into that big gear and spin up the hill at a much higher cadence then most other people I ride with are on their smaller cassettes. My knees very much prefer this, vs. grinding up the hill.
I'd actually consider 160 or even 155 cranks perhaps, but they are hard to find for road group sets.
Custom frame hole covers/grommets would be an excellent use for a 3D printer.
That's what I used to fill my fender mount holes............3D printer.
I've got long legs 78.5 cm (BB to saddle) but I chose to use short 165 mm cranks, I managed to cure the knee pain I suffered from thanks to the smaller leg articulation. It is recommended to reduce the amount of teeth on your chainrings to make up for the smaller lever force, I have 50-36T.
Sugru for frame plugs/grommits. It's a material that you mould how you like just like putty then it cures and becomes rubber.
Was going to say the exact same thing!
yes! Also use it for bottle cages to improve retention.
i was going to say some normal silicone calk either clear or some are in colors that may look a littler better. and it can be removed easy as well. i assume that is what you mean by putty but yeah seems like the obvious choice.
@@bretmohler9719 this has worked for me in the past. I built up a Propel SL from scratch with UltegraDi2 and there were a few grommets that weren't quite the right size. A little bit of silicon did the trick
Cracking, cheers Andrew!
I use 165 cranks on my bike. It's what I find to be more comfortable. I'm 6'1, some of the locals think I'm crazy for running cranks that short
what bike frame have you got?
@@velo1337 Diamondback podium, size 54
Let's see who's crazy after they require knee reconstruction surgery........
not crazy John, just slower than you would be on longer cranks...depending of course how much of your 6'1" height is leg length...
Bryan Oliver you have it almost correct “you can spin faster...with shorter cranks” more accurately “you must spin faster...with shorter cranks”. It is all a matter of physics, shorter cranks require more foot force to deliver the same force through the chain, because this additional foot force “feels” harder riders typically change to a smaller gear (and travel proportionally slower), if you do spin faster you can get back to the equivalent speed of longer cranks but typically riders will stay slower and make the observation that they are riding “easier”, of course you are, you are riding slower. You get nothing for nothing, there is no mysterious extra force the suddenly appears with shorter, or longer cranks...all the best.
Using longer cranks not only closes down the hip angle, it also tightens the knee angle. It has the same effect of reducing saddle height. If you swapped from 170 to 172.5 you would have to drop saddle by 2.5mm to maintain same knee bend. Then at the top of the stroke your knee is coming up an extra 2.5mm thus giving the effect of dropping saddle by 5mm therefore increasing load on knees.
As a technical, nerdy engineer, I really enjoyed Ollie’s well thought out, detailed explanations on this episode. Thanks Ollie 🙂
What type engineer are you?
Thank you for answering my question Ollie. You guys are awesome.
With regards to different pedal standards, Shimano made their Dyna-Drive pedals and cranks, which used a 1" thread. The idea behind them was three-fold: offer an aerodynamic advantage by allowing a lower saddle height, create a more stable footbed, and give more cornering clearance due to the low-profile pedal body. I have them on my Dura Ace AX aero bike. It was also offered on the 600 AX groupset, and in a different design on the Deore touring groupset.
Loved going from 172.5 to 170s so much I really want to try 165. Even with the 70s I can hit my chest with my knees.
I moved from 172.5 cranks to 165 cranks, and I was able to generate 20 more watts at the same HR the day after I got switched onto the shorter cranks. It makes a huge difference as your muscles are closer to their optimal length to generate power, and your foot doesn't have to travel as far to do the same cadence so you don't have to move your legs as fast to cover the further distance with the longer cranks. I would say it is something that can really increase performance once you adapt to it. I highly recommend it.
@@endianAphones I'm 5'10
Joe Blommel jeez. I’ve been trying to convince my 5’ 5” friend (really short legs. He basically cannot ride a 50cm trek emonda because its seatmast doesn’t go low enough) to go with 160mm cranks but he has been gaslighted so hard that he truly thinks that if he went with 160mm, he would lose all sorts of power. It’s very sad to watch him struggle to pedal with 170s, because he will sit very upright, even in the drops, and flare his knees out to make room. I wish he could see all these people (including me) who have gone to shorter cranks and gained power.
@@404nobrakes I've got a longer torso and shorter legs for my height, and the longer crank arm thing is old school thinking about one aspect of a larger picture. The best answer i've learned is that this is a big "it depends" answer for what someone is trying to do.
love my 150mm cranks on the roadbike. My utility/travel bike has 152.5mm cranks that were cut and drilled from 175mm cranks, it had long flat section to allow new hole
Ollie is great at explaining some of the more technical stuff for a bike simpleton like me.
I had a cheap so-called mountain bike in the 90s with 28/38/48 chainrings attached to 1-piece 165mm cranks & a 28-14 5-speed cluster. I rarely used the 28t chainring & was tired of running out of gears at the top end. So I swapped the crank out for a 115mm & trained myself to pedal at about 140rpm to maintain linear speed of the pedals. It took a few weeks to get used to it but it was great being able to go faster than 50 km/hr without spinning out.
Back in the day it was all about length....175 or longer....a few years ago I put 165s on my road bike and they are great......easier to spin at high cadence and much gentler on the knees
I switched from 175 to 180 on my road bike, and they are great. I have no problem maintaining nearly the same cadence as before, and less force needed for the same power, so gentler on the knees (in my case, anyway).
It should be more about riding the correct length that feels good to you than "shorter is better" or "longer is better". We've all got an ideal length and it's generally going to be at least loosely based on your leg (specifically femur) length.
I can spin the 165mm on my track bike, too, but I can definitely feel that they're much too short for me.
@@nwimpney how tall are you?
I love using shorter cranks as I feel more comfortable and I can get on top of the gear easier
got short legs (typical hungarian)- too often w/stock cranks (175 & 170 ) I felt I needed to adjust my position seat felt too low/too high, fore/aft - a bit frustrating to be honest- then, I tried 165s and felt dialed right in- hilly centuries /urban commutes. everything just works feels right from start to finish. the final sprint home even after a long ride gets the hr peaking max- double plus good, you know ?
if you got issues like I did, it is worth the investment to try - the payoff will make you wish you tried sooner
172.5mm to 160mm cranks here and the difference is amazing. I can get more aero, stay aero longer and have more power in an aero position thanks to the shorter cranks opening up my hip angle a few degrees.
Ollie: Nice job explaining the forces in short-vs-longer cranks and disc braking.
I agree with Ollie, have never had any issues with a double chainring up front. Have logged 40,000 miles in the past 5 years including 10,000 on gravel, have never once adjusted or dealt with any issue with the front derailleur on any of my bikes.
In regards to the disc rub - sometimes the actual mount can become warped (or be warped right from the get-go), in which case you might need to get the mount re-faced. You can attempt this yourself, Park makes a tool for this, but unless you are very comfortable with doing this kind of thing (and have the cash to buy a tool you might use once or twice), take it to a shop and have them do it. You can also try visually re-centering the caliper. I tried the centering tricks from GCN on my rear caliper many times to no avail, then I grabbed a flashlight so I could see where the pads were sitting and just did it by eye, and I haven't had a problem with rub since.
Should you ride shorter cranks? No. What you should do is test various crank lenghts. My local shop had a power meter hooked up to a fit bike. I tested 175, 177.5, and 180 length cranks. The test was holding a harder pace for 5 minutes. Then look at what the heart rate was. 177.5s lowered my hearrate (for the same output/time) by 10% over 175s. 180 was only 5% better thann 175. Unfortunately no-one makes 177.5 anymore. So all my bikes have 180 (the next best thing). Oh, my inseam is 38 inches. Get the test done, find out what works best for your leg lenght and spin style. (The best way to cofirm results would be to do the test 3-ish times over a period of several weeks. It's also best to do the test mid season when your legs are in the zone - i.e. not at the end of the season when your legs are toast, not at the beginning of the season when you're legs aren't up to speed yet).
I've recently upgraded from 175 to 200 mm cranks on my mountainbike. Should have done this years ago. The amount of torque I can put out now is enormous. I am 2 metres 6, inseam is 104 cm. crancks should be 10% of you length, or 20% of your inseam.
Not true, you just made up a number.
@@cracked229 Yeah, well, that's just, like, your opinion, man.
@@LordLlurch please do explain how you came to the conclusion that "cranks should be 10% of you length, or 20% of inseam." I'm 182cm tall which would mean I need a 368mm according to you doofus.
10 speed tiagra cranks work fine with ultegra, might need some tweaks but really it makes no difference.
Agree. I use a 105 7000 chainset (165mm by the way!), with a Sora 3000 9 speed gearset and 9 speed chain. Runs fine. Bigger issue to me seems going for a 34 inner ring rather than a 36 will give a negligible reduction in gearing (less than the you would achieve with a one tooth bigger rear sprocket). Is it really worth the effort?
Totally agree - might even be a bit more quiet in the drive train.
Agreed. I've used 11 speed cranks on 10 speed for years, and vice versa- just a case of setting up the front derailleur limits properly.
agree. 10 speed chainset definitely works with 11 speed groupset. John himself said so on a previous episode!
For the guy that wanted grommets or plugs for his carbon frame holes he's no longer going to need, try a bit of plumber's putty. You can dye it (within reason), it's waterproof and, if you get sick of it, you can scoop it out with a dental pick and wipe it right off.
I'm 1.70 with an 52 frame size, I used to ride 175mm cranks, and changed to 170mm, the difference is huge and, personally, I feel like a I do less effort now than with the longer cranks
You are correct Daniel shorter cranks transfer less force through the chain and apply less force to the cassette, or in other words less effort. If you want to go the same speed as you did with the 175mm cranks, however, you will need to produce proportionally more foot force with shorter cranks (a.k.a.more effort)
@@kiwisteve408 Yes, I noticed that when doing time trials, however IMHO, a 53/39 × 11/28 should go with 170mm cranks, and a 52/36 × 11/28 should go with 172mm or, if you're a big rider, 175mm. Nonetheless, you always can do strength exercises and training to compensate the effort needed.
Went from a 172,5 to a 170 recently. I can really feel the difference. Especially after a long ride.
Mee too.. went from 175 to 170.. way better (I am 1.8m tall)
okay surprising im pretty short only 5"6 and i will probably change the cranklength from a 175 or 172,5 i think to 165.
@@xxzmk definitely go for it. I'm 5'7 and switched from 172,5 to 165 cranks this year and it felt great. I can't tell much about the actual power output but my pedal stroke feels much smoother now and I'm able to maintain a higher cadence (especially when riding in the drops). No negative side effects at all.
@@pklosow nice thanks for the info man.
@@endianAphones I'm also the same height and used 165 on all my bikes for many years and never looked back. I have a new 170mm takeoff for sale if you're interested, but I recommend 165.
remember that with shorter cranks you will need to raise your saddle. A smaller crank will describe a smaller circle (pi x d) so your cadence will rise slightly. Wiggins used 170mm on his road bikes and he is over 6'
Those Victorian pedalers would have been fun to watch when the
pedals came off, especially if the front wheel was eight feet tall. HA!
A really cheap hole plug are foam ear plugs. Squish, insert, let expand, trim to length and paint to match specific frame area where they'll be installed.
You really did a nice job on that video. Smooth tranquil communication skills.
Silicon sealant comes in a few colours , a good hack for covering up gromit holes
Yes, I've used black silicone sealant before and is available from most hardware stores or plumbing supply stores.
For the Canyon frame: You can use Sugru. It's moldable glue that you can use to fill the hole and even paint it to match. When / if you want to remove it you can just pick it out and it will come out in one or two pieces. Dry its more like rubber than a silcone sealant making it really easy to live with.
Aisaku Pradhan Or a thought I had was clear silicone sealant that a plumber would use - easy and transparent way to fill a small hole. About £3 a tube from a DIY shop.
Flexible Silicone sealant for the frame holes.
You could fill the holes with caulking and holes will be waterproof. There are many colors to choose from so you could probably find a color close to what you need.
#askGCNTech are all those tools actually used for bike maintenance, or just set dressing?
They picked the right guy for GCN tech! You do an excellent job.
I used to use 165mm cranks when i was school racing on restricted gears to deal with the cadence.
Thomas Bedford I wonder if Shimano made 150-160mm cranks, how many juniors would go straight to 150s just to be able to spin 200rpm in a sprint.
Yes, short cranks are ideal if you have limited gears, or on rollers, where force has negligible affect on speed compared with rpm. However as soon as you need force to climb for example or ride a bigger gear the torque of the longer cranks will produce more speed for the same foot force.
In regard to the recommendations for the user looking to swap the 10 speed crank on an 11 speed system, I wanted to add additional points that were omitted in the video. 1. Don't put a 10 speed crank on an 11 speed system, since the chainrings are thicker and spaced further apart, the chain has a far higher likelihood of getting stuck between them, which is the main reason not to do it. 2. If you are up-sizing your cassette as recommended in the video, you will also likely need to install a new chain, or additional chain links, as additional links will be needed to take up the additional chain wrap required by the larger cassette. If you don't do this, it can bind the chain and prematurely wear on the rear derailleur when in less favorable big-big chainring/cassette gear combinations.
#GCNTech I've used "Sugru" moldable glue to fill those holes in the frame. It's amazing!!!! You will be happy with it.
*Knee Pain FYI:* Shorter cranks (150-165mm) are often used with recumbents due to the rider being very fixed in position (i.e. no shifting/standing) and the not uncommon consequent knee pain that "regular" length cranks cause. For uprights, apart from the usual seat and pedal positioning solutions, this _MAY_ be worth a try.
And Mickie Freiburg used SUPER long crank arms when he became a track cycling world champ, as this suited HIM at that time. We're all a bit weird and different from each other, so if one has the possibility try something new/different - go ahead!
@07:36 no it's not a *requirement* for disc brake either - many (older) bikes (mind included) with disc brakes work just fine with QR. I suspect most rim brake bike hold-outs are after wheel changing speed and that's the reason.
Ollie, I feel bad that you didn't get to go to your home county to look at the World Championship bike tech, but glad that you made us a video. If this keeps up, I'm just going to assume that you're the regular Tech Clinic presenter and Jon is a temp worker.
On different bikes I had 172.5 cranks and 165. And while I think I could get used to one or the other given enough time, the most disruptive thing is just moving from bike to bike. I felt most comfy naturally at 165 so I went to 165 on both.
I gave up on the front derailleur. We have 9 bikes in our household. Started the year with 5 front derailleurs. We’re down to 3. Goal is to go down to 1 front derailleur and 8 1by systems. The 1 front derailleur we’re keeping is DI2, thus worth riding. Everything else will go.
Shorter crank arms allow for more ballistic pedal movement, in turn (no pun intended) allowing the rider to turn over the pedals faster. You can improve power much more training and experimenting with gear ratios then having a longer crank.
Great video, but Oli made one mistake when talking about pedal threads. A left-hand thread on the left pedal will actually cause the pedal to loosen with the forwards pedalling motion. Pedal threads where designed like this when bearings were a little less reliable; so when your pedal seizes up, it'll simply come loose rather than snapping your ankle.
37in inseam & run 180mm. Tried shorter, performance and comfort suffered.
we all know long crank length also means long you know what
39in inseam & run 180mm, and want longer. Getting sick of people telling me that short legs need short cranks, Average legs need average cranks, long legs need average cranks.
I didn't notice too much of a performance difference either way, but with the longer cranks my knees feel better after hard riding.
Fill your holes with CT 1 .. you can get it in different colours , its like silicon but not and wont damage . Completely waterproof.
Ollie mentions that with different crank lengths, altered torque doesn’t matter much because you can simply change gears. But isn’t it so that with a longer (crank) arm, you generate more torque with the same pedal force? Torque = force x arm. So changing gears is another matter? Of course, this is apart from the whole biomechanical issue, but still.
For that Canyon bike, to cover the hole i use a silicone glue, that will make it a great water resistance
Frame grommets: black Sugru, works really really well
#askgcntech what riding surface causes more tire wear? Gravel or tarmac? Assume same tire, same rider, same power, same tire pressure...
Chainrings on Shimano, despite being the 110 distance, are not universally interchangeable: They have grooves and ridges that won't match those on the ends. You'd need to file a bit. I for one recommend getting a Specialites TA set. As long as the minimum teeth distance of 12 is maintained, you can use any combination!
For recumbents, so many people opt for shorter cranks as it makes people just spin and more comfortable for the hips and knees. I think many are 165 and 155
Great info, love the show!
Longer or shorter cranks? Let's look at this like we would decide what size of chainrings to equip. After all, the pedals are going around in circles, correct?
In terms of efficiency, it takes more effort/energy to turn a 53 tooth chainring than a 50 tooth compact chainring. It easier to turn the small ring, thus less energy.
A smaller crank will then be easier to spin around because its radius is shorter and is able to travel faster around its circumference, so you can maintain a high cadence longer.
Shorter cranks don't mean less torque at all. If we rode by just hanging a weight off the pedal then that might be true. But we ride by pushing the pedal with our foot, which is attached to our lower leg, which is attached to our upper leg, which is attached to our torso. It's all a system of levers at different angles, powered by muscles that have to contract, the performance of which is related to how far and fast they have to move, and ultimately limited (in anything other than a sprint) by your aerobic capacity.
Even if you could argue that shorter cranks might have less torque, the counter argument is that you can spin a higher cadence for the same pedal force and pedal speed, meaning power is unaffected.
Matthew King But cycling at a higher cadence than that which you are accustomed to is not so easy... whilst a longer crank arm gives you the same torque with less pedal force. Irrespective of where that force is coming from exactly.
My gravel bike has 175 and my road 172.5mm think I prefer the shorter ones. Give me less hip issues.
@Joao Belo but the diameter of the circle that you're pedaling (and therefore the distance your knee is moving) is reduced by 5mm.
Super like for the response about front derailleurs.
Really, if you can't set-up a front mech maybe bike mechanic is not the right career.
"I'd like front derailleur to stay exactly where they are" except when you're shifting gears in the chainrings or changing your chainrings sizes!
For two years now I'm running a 52-34 instead of 52-36 with 11-32 on Ultegra Di2 without any trouble. And it's quite a cheap thing to try.
Riding cranks cut down to 5 1/2" in roller races wins every time. 240 rpm
Very impressive.
The experience of recumbent riders is very relevant here. Many ride truly short cranks 130 not being uncommon, I use 143 the odd number being due to having long hollow cranks cut down. Always the same experience is that it takes 1000km or so for your legs to get used to it, many reports of tests on crank length are based on measuring the performance difference before the legs have relearnt the muscle memory. If you want to try shorter cranks then give it plenty of time before rushing to a judgement.
Colin Rose Perhaps recumbent cyclists need shorter cranks because gravity and maybe even biomechanics is against them, thus they are unable to generate the force required to turn longer cranks around?
Lars Borghouts my post was about giving yourself time to get used to shorter cranks, I ride an upright and a recumbent and power output is identical for me, albeit the recumbent is faster for a given power output.
Park Tools should develop a disc rotor press. they could machine various tolerance molds to place a bent rotor in, apply just the right amount of heat, then cooling the metal rapidly to harden it again. like a George Forman grill for brake rotors.
or am i just high?
That was a strange request on the last question. I have no problems with my front derailer, it works perfectly fine. Admittedly having di2 makes changing gears easier but even with mechanical gears I have not had any problems.
3D print some blind cable entry pieces, that would take a bit of measuring, to replicate them, and maybe 3-4 test prints...
Front derailleur is good for road biking,.. anything fast and on road... FD is essential..
Get the cassette, if you don’t have it. I put a 32t cassette on my 52/36 chainring and what a difference. 52x25 is no longer cross chained. 😀
Before replacing the calipers:
Sometimes when you take your wheel out of the frame, there's always a joker that presses the brake lever, maybe that happened to you..
Remove the wheel and brakepads and with an 8 or 6mm allen ball wrench, carefully push the pistons back inside.
Reinstall everything, reposition your caliper as shown in the video, brake a couple of times and test it again.
Never clicked a notification from UA-cam so quickly 😂😂😅
Craig Bishop same 😂
i'd honestly like to find a set of 185mm or 190mm cranks, i've got long legs and they don't like high rpm's trying to top out speed. course i only have a 21 speed mountain bike at the moment but can hit ~25mph flat out but just can't pedal at that speed for long because my legs don't like the short throw. you could say i'm a bit more like a diesel with a long torquey throw as opposed to a shorter higher rpm output. maybe someday i'll get the $ saved up for a good road bike and can get a nice group set that'll work better for me. my longest trek with my current bike atm is ~40 miles one way before my left hip gave out and i needed a lift back home.
Zinn make long cranks but are expensive TA Specialites make 185 cranks, i've ridden 180 mm cranks for years and love em!
Technically, your foot speed is greater for the same RPM on a longer crank than a shorter crank. I have found that at high cadence, a shorter crank results in less saddle bounce.
Re your analogy of a motor, a diesel motor is more like a short crank, and a high reving motor more like a long crank.
Longer cranks are way more aggressive on your hips and knees.
After having watched the show I miss Jon a little less. Well done, Ollie!
#ASKGCNTech Thank you for such a great show. One of the highlights of my day. I have a Canyon Aeroad that came with regular bar and stem. Looking for a 1 1/2" integrated carbon bar system and striking out. I live in the USA and Canyon does not ship here currently. Need help! Any recommendations?
Concerning holes in the frame: What about just putting in a drop of polymer kit?
#AskGCNTech Can you tell us something about experiments with non-standard wheel sizes in road cycling (other than 700C and 650C)? Even UCI allows wheels to be anywhere between 55 and 70 cm in diameter so someone must have tested it. Any experience with 'mullet' road bikes maybe? Tyre widths have increased a lot recently - why isn't anyone talking about the wheel size? I can see a potential for a whole video in this topic ;-)
Anodizing is an option for colored chainrings
tiagra cranks work just fine, the spacing difference is practically nothing. The same for mixing 5800/5800/9000 and 7000/8000/9100 cranks and FD, a half millimeter difference is nothing. The real question is why bother, 34/36 is only a 5 rpm difference in gearing. The cassette is more of where you should look, 32 or 34 in the back.
You are NOT going to be able to recruit your muscles in a greater range of motion on a shorter cranks - quite the opposite, they are going to be recruited in a smaller range of motion. However, you ARE going to be able to recruit your muscles in a more efficient range of motion.🤓
Interesting how short cranks are now better for hip angle when for decades short people were told they'd get used to the same length someone five foot ten would be comfortable on.
Yes disc version means lots of problems but proper rim brakes no even one🙂
Here we go with the disc brake hate...... it's getting old!
...... and you're wrong! Rim brakes, like disc brakes, aren't perfect...... they have inherent problems too!
@@rodneymcintosh1484
No hate but practical experience.
I have bikes with both system therefore it is objective😉
My serious triathlete friends, even tall ones, are using 165 mm cranks
Another perspective with short cranks - short story they didn't work for me, mostly from a dislike of how they felt when standing..
I'm 1.87 m and long legs (1035 mm from pedals to saddle). Normally use 175s in all disciplines (road, TT, CX, MTB). I use short cranks extensively during certain periods of the year - winter fixed gear commuter has track cranks, 165. No issues there, very small gear for pedaling through snow (46x 19-21)
The short cranks feel a bit heavier to push, but quicker to turn (less torque issue). Not a big deal, you adjust in the gears and move on - they had no effect on threshold power, but did decrease maximum power either seated or standing. What I found was a deal breaker was standing up on the pedals; the tiny circles allow for very little leverage either for climbing or sprinting - and yeah, I could pedal faster but I already can hold 200 + rpms for about 20 s (I used to win the local roller races).
I also didn't feel difference on TTs either, never felt impeded in hip angle, I'm flexible enough that my main issue on the aero position is not hip/back issues, it's vision - my head is too low and have to crank my neck too much. If you have tighter hips/glutes then they may work for you.
One additional factor - I use my pedals way back on the foot; not quite mid-foot position but as far back as a speedplay extender will allow. Maybe that could be a factor as well.
Rod Diaz holy cow. 1035mm?? You’ve got some stilts. I would say you definitely went past the threshold of “shorter” and went to “absurdly short”. My saddle height is 760mm - 275mm shorter than yours - and I find 165mm cranks to be adequately short. I could probably go 167.5 too. If it matters, I am 170cm. I have a friend who is 165cm and has much shorter legs. He’s using 170s and is reluctant to try 160s.
Rod Diaz also, the main issue with standing on shorter cranks is that your cadence has a much harder cap. Spinning up 10-20rpm faster to achieve the same power is easy-ish when seated. When you’re doing a balls-to-the wall sprint at 100rpm, it’s not so easy.
@@404nobrakes yeah, I found that unpleasant - I naturally don't like spinning when standing and prefer 80-85 rpm when off the saddle. Even full sprints I prefer (and have better power readings) at 100-105 rpm than using a smaller gear. This is also probably related to the very long legs!
#AskGCNTech
Hi, love the show!
I'm looking in getting a CX bike, but I'm on a budget. So I'm looking in making a CX bike which I can use as a road bike as well. Would I be able to fit a 2x chainring on a sram 1x setup? And what other things should I know about?
Thanks!
Thanks Ollie. I watched this just after I got out the shower, glistening, dripping moist with the dew of anticipation. I didn't even have the water on.
Lol
Snort!
As for the front mech.. we will probably all go internal at some point.
#AskGCNTech I am wondering if it is possible to have a crankset with a 52/34. I currently have a 50/34 and I feel like I could go faster on the flat, but I don't think I can go back to the 36 as the smaller ring. Is the gap too much, or it could make it work?
I forgot to give you all the info. Ultegra r8010 mechanical 170mm
It is not recommended, but it can be done. There is a higher risk of dropping a chain when downshifting to the smaller chain ring.
Sure you could use Sugru to make some grommets for the frame holes
#AskGCNTech I've been wondering something pretty specific for a while. Can I convert my cyclocross/gravel bike to a passenger bike if i want to? what would I need to do for this? a rear wheel which can carry more weight? a rear rack seat? Would I be better off getting a trailer for the bike instead if I wanted to carry someone. I don't know if I'll actually do it but I really just think the idea of it is super fun. I have a Felt F65x.
How do you fix a hydraulic caliper piston that's not retracting symmetrically (at rest one piston sticks out from the cylinder far more than the other), and though the caliper is centred, one piston still rubs.
If I’m reducing my crank length from 172.5 to 160 or 165 do I need to change cassette or anything else as Ive heard people saying you should.
You wouldn't need to change the cassette for any reason other than to achieve the same relative gear ratios. Going significantly shorter with you cranks means that for the equivalent number of teeth front and back you'll have to produce more force for the same cadence - if you don't feel you have easy enough gearing to get over climbs with your shorter cranks then changing cassette to have a larger big cog might be a good idea
Hello Jon...what are the differences in components of Shimano tiagra and Shimano 105 that should be considered while upgrading...hope you are back...love the show...#askgcntech
#askgcntech one of my legs is almost an inch shorter and is much weaker than the other. What can I change on the bike to compensate for that? Shorter crank arm, shoe inserts, cleat spacers come to mind.
John answers the questions the best!
The 105 chainrings are not compatible with the R8000 crankset. I tried this about two weeks ago, and one of the Ultegra arms has a little "swoosh" that makes the 105 chain rings not fit.
Hi!
I have a bike-project going on, where i mean to mix different bike-components. I understand there is different lever and travel pull-ratios across shimanos range of different groupsets. Can you make a video comparing them, and their compatability with one another?
#AskGCNTech
For the person who wanted to powder coat, why not investigate whether you could get the chainrings re-anodized.
#AskGCNTech When I let go of the handlebars I have to lean towards the right side to keep going straight. What can cause this? I have not had any crashes and have not changed anything on the bike. This has progressively been getting worse over the last year.