Why You Need Shorter Cranks
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- Опубліковано 29 гру 2023
- Shorter cranks not only solve many bike fit problems, they also have been proven to benefit the key performance measure that all cyclists desire - more power!
More and more research now shows that when cyclists change to shorter cranks on their bikes, they not only reduce the effects of hip joint restriction, but they can get more aero, actually produce more power and therefore ride faster and further.
This bike fit and performance hack has been discussed for years in the cycling exercise science literature, but very few riders know about it and even fewer have done anything about it.
I'm about to find out for myself. I'm 192 cm tall, have 175 mm cranks on my two road bikes, and am about to change over to 160 mm cranks that would normally only ever be fitted on the smallest of bike frames.
Will this help me reduce my hip pain, ride faster and improve my power figures? Let's find out! - Спорт
A few weeks before the 2012 Olympic TT, it was suggested to Bradley Wiggins he might try shorter cranks than the 177.5mm he usually ran. He won the event using 165s…
I've heard the same story but I thought he went from 177.5 to 170?
I went from 170 to 155, and it's best upgrade ever. My height is 5' 8" with an inseam of 80cm.
Did you see any downsides early on, or in the longer term?
Road bike, mtb?
@@podiumphysio657 None thus far. I've been using them for over 10,000mi.
@@00brs Road and gravel bikes.
Cheers from Melbourne,
Very clear and articulate commentary. In a week's time I'll be swapping my Ultegra 170s with 160 carbon cranks ( I'm also going for a ceramic BB ). I really don't know what to expect but the overall consensus seems to be that the positives far outweigh the negatives. Not a leap in faith but one in optimism!
Good luck with your channel!
Let me know how you go!
I changed from 175mm to 165mm some 7 years ago and it made a huge difference from a comfort perspective and I didn't perceive any long distance triathlon performance decrease. I'm 187cm tall and applied this advice from a book: The Well-Built Triathlete, by trainer Matt Dixon. This book also helped with my swimming through some non-mainstream advices.
Yes I've done 2 rides so far with the shorter cranks and my hips are definitely happier. I'll be posting some more info, data and reflections on this topic very shortly.
Self-experimenting now. One month into the experiment. I went from 170mm to 160mm. I was constantly sliding forward with the 170mm cranks. Hip pain, knee pain etc. I'd been to a couple of different fitters with no such luck. The 160mm cranks have helped my trunk and pelvis stabilize much better. No knee pain, no hip pain. I did Raise my saddle and had to pull my saddle aft to get comfy. Much better power and comfort so far. Only down fall is the wind up. I'm not racing so it really doesn't bother me. Just takes a few more pedals revs to wind up on a group ride. So far, so good. Also, I'm 5'8" with an inseam of about 77.5cm.
Yes the issue of pelvic stability is definitely worth considering. In my group rides we have an ex Olympic cyclist who seems to have huge pelvic lateral tilt. I'd love to see him on shorter cranks to see if that would improve things.
I have been promoting shorter Cranks for a decade now.
It is the first crucial step when getting ones self fitted to
a bike, get that wrong and it will then impact down the chain.
I fully agree, the shorter the better. I have had fitters say that
I should use 170mm and they were all incorrect, the whole
pedal stroke circle was to large and that resulted in never
being able to fine tune the saddle position, It drove me
around the fu*king bend.
Its too early for me to form a strong opinion, but I'm starting to collect some data and feel for the new position. I'm sure I'll need a bit longer to give a truly informed commentary.
I am 182.2 cm in height and I and have been using 210mm cranks for about ten yrs and love them (I am using the same crank brand/model you highlight in your video). Up to ten yrs ago I only used 180mm length cranks. About 3 months ago I had to swap bikes to my old racing which has 180mm. It felt like I was on a kids tricycle, I had less torque to accelerate up hill and I had to spin faster to get the same top speed (I naturally spin 210mm cranks between 100-115rpm). There was noticeable decrease in ability's when using my indoor trainer (Tacx Flow). I put the 210mm on the bike I swapped to and I just love it. I also use 210mm cranks on my mountain bike. The other benefit of using a longer crank is you can use a smaller bike/lower your seat height (another way to get more aero and lower your center of gravity. When it comes to mechanical advantage I think it is unwise to compare rotating a crank to doing a squat. The leg motion may be the same but the objective is very different. You are not creating torque when you do a squat. The sport specialist you mentioned is another example of sport professionals attempting to defy the laws of physics. You see the interview with former pro cyclist Adam Hansen regarding crank length (he only used 180mm).
You must have some amazing leg speed spinning a 210 crank at 115 RPM!
I'd love to see some good quality footage of you riding on your indoor trainer from side on so I can put it through my Bike Fit Video processor. I think the data produced would be amazing.
I will find a way to record one of my indoor sessions. I had the privilege of being coached one one one for a year by Philippe Mauduit (a Dir Sportive at FDJ Cycling team...he was the last Dir Sportive for Thibaut Pinot ) he help me build up high cadence@@podiumphysio657
210?? 210mm cranks? @115 rpm? 182cm tall 🤔 You didn't mention what size bike you have that take a 210mm crank? May I also ask how you originally determined that 210mm cranks were the thing for you? Thanks
I'm only 5'6" (167cm) with 30" Legs (76cm), and I use Zwift often. I machined/tapped a second set of holes on my 172.5 cranks down to 155, and *WITHOUT QUESTION* it smoothed out my circular motion, I stopped hopping, and my overall watts appeared immediately to go up by 5w. I'm a confirmed believer.
Brilliant! I also think pedalling smoothness is under-rated
which cranks you use in 155 ? my is shimano 170
@@khochiakeng I began with 175, yet there IS enough room to drill and tap using a 170. I have a lot of space between the bores.
@@khochiakeng Not sure I understand your question sorry.
It all depends what type of riding you do; everyone has an optimal crank length in that regard. What puzzles me in these debates is that leverage and torque are never discussed, so thanks for at least mentioning torque and leverage loss by going shorter! For myself I much rather ride a crankset length that gives me that leverage and that extra torque to transfer to the pedals when needed comfortably. I'm average height 5'9" and ride 172.5mm cranks and the difference is huge between 170's and 165's when climbing on my routes for me, I'm not a spinner but keep up a good rpm with a 12sp drivetrain. When I've tried shorter cranks, I actually strained my knees and it felt slower! So, it's all about finding out what works comfortably and efficiently for yourself.
I 100% agree about finding what works for you as an individual. I've decided not to change my cassette or chain rings despite the leverage loss, as I very rarely use my lowest gear here in Adelaide, so nearly always have a bigger cog to drop into when necessary.
In theory there's a leverage loss. But in practice one could generate more force on the pedals with shorter cranks. The weight squatting is the best analogy I've seen. I went from 170 to 155 without changing my gearing. When I'm on my lowest gear climbing a steep hill, the perceived exertion is less while I'm generating the same power as before. If my power and cadence are the same, that means I must be acting on the pedals at a greater force. So for me personally there aren't any downsides to shorter cranks. I'm 5' 8" with a 80cm inseam.
@@jonathanwoo6597 Yep. Great deduction. I'm hoping my experience will bear out the same way over time.
The torque/leverage argument has been used for decades as an argument for longer cranks. However by shifting to a different gear you can freely adjust 'gain ration' on the fly, so leverage is not an argument.
@@martijndegroot9772 What I've seen is that there is so much more to the discussion than just this one issue of leverage.
I am 1.77m tall, I rode 172.50 cranks for years. I changed to 165cranks . It does have benefits as you mentioned. However my sprint suffered and my top speed dropped and power went down. So I am now experimenting with 170mm cranks. First impression sprint improved, cadence went down.
I'm about to find out...
On my first ride yesterday I was definitely more comfortable in the hips, and I felt that my sprint was comparable, although it definitely felt a little weird at full throttle.
Top power should come faste. Speed racer use shooter
@@podiumphysio657 An update. I am suffering backpain and kneepain with 170 cranks, I did not experience with 165 cranks. So, I ordered a new set of 165mm cranks.
Road Cycling Academy has a better explanation for this. Aside from being fit, one must know the type of ride, whether a cardiovascular or neuromuscular rider. Neuromuscular riders will benefit from longer cranks.
You can lower your seat which puts you further forward and your feet will be further back too. Both these will help push back on your pedals rather than trying to pull them back. Much better for cyclist who use quads rather than hamstrings.
I may play around with my bike fit once I have some baseline comparison data between the 2 crank lengths
I see a lot of comments from people stating their height and crank length along with you not mentioning your inseam (unless I missed it), but wouldn't it be better to focus more on your inseam length instead of total height when considering which crank length to use? To me it seems like a massive oversight to not talk about that but then again I'm not a bike fitter or medical professional so maybe I'm missing something.
I'm 169cm tall but have an abnormally long inseam for my height, which is 85cm so that'd affect what crank length I'd use compared to someone with a more average inseam from what know. I currently run 170mm cranks on all my bikes.
Yes you definitely need to take relative body proportions into consideration. As a bike fitter I use a video assessment tool to give data on joint angles, which I use along with my subjective and objective assessment, functional testing and of course client feedback to work out the best position and set up of a bike.
I'm 194cm and have 170mm on my road bike and 165mm on my track bike.
The 175mm originally on my road bike were too long and caused a lot of problems but on the track I am finding now that 165s hinder my power development on big gears.
I just lack the leverage to produce sudden accelerations and need to use a lot of force to overcome it.
Interesting. I'm making this change for the first time so am yet to/ about to see the results. My main interest is managing the stiffness and discomfort in my arthritic hips. If the performance data for 175 vs 160 is roughly the same I'd be happy. If there are any gains to be had that would be a real bonus...
@@podiumphysio657 What is your opinion on crank length when riders cannot select their gearing (like on a track bike) ?
I feel like 165mm limit my leverage and acceleration but I picked them thinking it would help reaching higher cadences. I have seen the study from Konstanz Uni on the positive correletion of crank length and power production during track starts and it made sense
165mm feel like the pedal is a bit too close to me when I tuck in for seated sprints, I get the feeling of falling forward onton the cranks. All of this makes me wonder if 170mm would work better with the aggressive fit and short saddle setback of my track bike.
Does it make sense to you ?
What would yoou advice be ?
@@WesternUranus Firstly I'm a roadie and have never ridden a fixed gear track bike. However on a track bike you can select your gear, you just cant change your gear once it is chosen! If your bike fit is done with a focus on knee angle at bottom dead centre, then at the top dead centre, the 165mm crank/ pedal would be further from your chest than the 170mm crank/ pedal.
If you are talking about the pedal at the horizontal, then you may need to push your saddle back a little and use a shorter stem.
In relation to the start of a track race, I've never done one, but I know that I can produce more power, and get to full power quickly on my 160mm cranks. I did this test up a 19% climb near where I live. ua-cam.com/video/P0qO6Wza58w/v-deo.html
For me, other than my hips being happier when I ride the 160mm cranks, I really dont notice a huge difference in "feel" between the 175s and the 160s. Once I'm on the bike and going it just feels like - riding a bike!
However if you are sitting on the fence, there really is only one way to find out for sure, which is to get a set of the shorter cranks and try them for a period of time. I dont think just one or two test rides is really sufficient.
As a short old rider 164cm high 69cm inseam. All my life i have had the choice with a small or x small bike getting the choice of 170mm or 175mm cranks take it or leave it ? Obviously i gave up . Until recently i gave it another go . On line crank length calculator bikefaff punched in the 69cm inseam and back came 140mm. 140mm surly that bound to be way to short ? Well no , found a 140mm crank from a cheap folding bike with 140mm cranks, swapped them over ,hay presto they work . Not only do they work as far as i am concerned they confirm the on line calculator, they are absolutely spot on for me . After years and decades being fobbed off with 170mm is the lowest normally take it or leave it .
Even on XS and XXS bikes for sale all come with 170mm cranks. Decades of waisted time .
No going back for me .
I've waited 6 years to give this a try...
Glad to hear you found a solution that works well for you. That is all that matters.
@robduncan599 I'm the same height and have used 155mm Rotor cranks since 2017. No downsides as far as I can tell.
Many years ago my training bike ended up with 155 cranks , this was due to no alternative tbh. I'm 5'8" btw. I never raced on them but did long rides and there was less tiredness and apparent speed and efficiency improvement. Not scientific but I might give it another go
Why didn't you stick with them?
@@podiumphysio657 ah well, probably got a different bike and set up, don't remember what exactly happened. I was mostly riding 66" gear fixed with this and found my average speed was higher on long rides without being more knackered.
Nowadays I would probably try and be more scientific, no power meters or even heart rate monitors for me then.
I was doing regular 80 mile rides on it though.
I'll see what cranks are in the workshop, probably have to be kids mtb triple to bolt to the winter bike, it's z2 season so might be a good time to try.
@steveprice9737 More speed and less fatigue = win /win 😀
can you do a test at a specific power for set distance and compare the 2 rides, also do a test using a specific gear ratio for a set diatance and compare rides. intreasted in power diffrences and personal feel.
Yes I've had a similar suggestion already - riding to power on the 2 bikes and comparing heart rate data. Planning to start on this very soon...
You’ll need to let us know what other changes are needed when going to a shorter crank. Straight off, there will be a raise in the saddle height so that your max extension doesn’t change, and which will increase your reach. Anything like that.
Yes of course. I had the local bike shop install these cranks for me while they were doing a regular service on this bike, and they automatically decided to put the saddle up an additional 15mm. (Fair enough...) This was how I rode the bike (my Tarmac) the first time I tried it out. However because this bike has a proprietary stem, which is at the top of the steerer tube already, and cant be flipped, I then decided to drop the saddle back to where it was, otherwise I was going to have something like a 12cm saddle to bars drop which is way too much for me. You will see what I mean when I post my next video on the bike fit considerations of these 2 setups.
My knee extension actually doesn't change all that much between saddle heights, but my ankle extension does!
Because of the advantages gained with the shorter cranks, at this stage i really dont think I'm going to need to change my cassette, chainrings or anything else at the moment. I'll do an update in a few months to see if my feeling about this changes.
Example 165 Short crank arm with 52t chainring or 172.5 crank arm with 48t chain ring..
Sorry was that a question? Not sure.
I’m 5’7 (170cm) with relatively long legs with 32 inseam (81cm) and went from 175-170-165. Felt so much better. I’ve tried couple of 150 & 155 but felt power output wasn’t quite there although I did feel comfortable. I feel like 160mm would be a sweet spot for me but I can’t seem to find any Carbon MTB cranks in that size as finding one in 165mm is already hard enough. But yeah… I’ll never go back to 170 or 175
Sorry to hear you cant find the cranks you want. I just asked my local bike shop to get some in (160mm SRAM) and they were there within 2 weeks. Maybe I was just lucky.
Hopefully you will come across some soon!
@@podiumphysio657what kind of SRAM cranks come in 160mm length? Do you have a link you can send? Thanks for your content!
@@ericandeddy Hey there. I've actually just ordered a new bike and asked the LBS to put SRAM 160mm cranks on them. I dont know how they place their wholesale orders however I did a quick search on Amazon and it seems they might be available there...
www.amazon.com/SRAM-Rival-12-Speed-Crankset-Black/dp/B092VL7TMC/ref=sr_1_2?crid=8KCD2SVR20JI&dib=eyJ2IjoiMSJ9.T1rRPkXPwxKIrEdTwGxFFYKMLMofl5jHHI1cUA7qIJVTesBdRuRitl6RyG51oC0XrbSwJpZL3IRD-u5I9uELIxTx9ZRgRvoL6CZ-MUFhWeu1o8-DGQH1wQ47flvPfqWIR9nTcKuMnNzG6Ted3gqNgZL4Ch9sDrTy1L3eQhNujHLvJy4VS-XDWhXo2Ui6YnkWxd3ODyjjjUO0B_KzoZHtSdDRFl4Y_ALqMPlXzSCgX-lUM1FL4XKldFULGZVP98TXrZq7AbRqFO-JzT3UbhIboRCVb28pgO7IFjCQ58A4JjU.rtfw9SFy-niKXtQWIjTKe_JtFOBrbIUtY6MVZyzgxDA&dib_tag=se&keywords=sram%2Bdub%2Bcrankset%2B160mm&qid=1710045687&sprefix=SRAM%2BDUB%2B160mm%2Caps%2C439&sr=8-2&th=1
@@podiumphysio657 thanks. Wish SRAM made Force or Red in that size. The sram rival cranks are heavy and you have to buy the whole crankset since the crank arms are not compatible with other sram chain sets
@@ericandeddy Yes cycling is an expensive sport/ hobby. But it is nice to get your bike set up exactly how you want it!
I am about 190cm and using 175 crankset, I am interested to see your results after the test as I am think it is shorter is better for the crank arm 🤔
I'm hoping to upload some videos very soon now with results...
I'm 5'11 with a 32 inch inseam, or 180cm and 81cm... can you recommend crank size based on my dimensions or is there a resource I can use to estimate proper crank size? Cheers.
Well not really, unfortunately. I decided to go to 160mm cranks because I have hip pain and I know from a hip angle perspective, the shorter the better. I went with the shortest cranks that were easily available from a mainstream supplier. I am also academically curious about whether such a big (and unconventional) change has any downsides. Based on my findings thus far, I'd suggest if you can go to 160 mm give them a try, but this is based on my opinion only.
If you have not already, have a look at the 2 latest videos I've made about shorter cranks. I'm also working on video #4 which I hope will be ready to publish either today or early the coming week.
I'm also 192cm ride a 59 seat tube and have always used 170mm cranks. My inseam is 'only' around 87/88cm for my height, however 175 always felt too long. I'm going to try 165. There are a few variables to consider with hip and knee comfort, seat tube angle, BB height, head tube angle etc. I personally feel they make bike frames with seat tube angles thar are too relaxed. Being over your BB more reduces hip pain and can allow you to get your knees, feet, back and hips into a better sync than a relaxed seat tube geometry. Let me know what you think, and how the 160 has been, thanks
Hey VW. I’ve been using 160s for 6 months and I’m never going back. Less pain and better performance all round.
@@podiumphysio657 Good to know
Subbed.
Great to have you on board!
If you’re 6’4” an plan on riding 160mm crank arms, what would the recommended length be for someone 5’ tall? Until someone can explain crank arm recommendations over a wide range of heights, I’m sticking with my current setup.
Well the whole point of this exercise is that conventional wisdom and tradition would have it that a taller rider needs longer cranks and a shorter rider needs shorter cranks. There are various tools online that can do a calculation for you based on leg length and give you a recommendation.
However I'm looking to move to much shorter cranks than are normally recommended because I have significant hip joint restriction, and because I'm academically curious about the results.
What crank model did you buy and where did you get it?
Sram Rival DUB 160mm 48/35. These are available on the SRAM website
My LBS ordered them in for me
While I am very interested in your results, at 75 my cycling is winding down. I have been building custom steel frames mostly for very large riders for several decades. Most modern bikes particularly road bikes are hard to get both good fit for the rider and good weight distribution on the wheels. While crank length is relevant, compared to other paramaters it is of lesser concern. But I do agree that shorter cranks are not detrimental. However with shorter cranks seat hight and seat set back will also change. As for aero position if you care, the difference is small if you average less than 25 km/hr. It is only at higher average speeds that any aero effects exceed rolling resistance. Example at 50 km/h the difference a total aero bike makes is 4 s per km, at 25 km per h it is only 1 second per km.
Appreciate your comments. Do you aim for a 40/60 weight distribution split in general? How do you decide?
Building a custom frame starts with measurement of the rider on a bike. I am for complete toe/front wheel clearance, not necessary for racing but for general commuting touring means tight slow turns while pedaling are drama free. This make the frame a little longer and the stem short, and reduces the load on the front wheel, to fix this I lengthen the chain stays to move the rear wheel further back. Lateral bracing of the chain stays removes lateral power flex. So a longer wheel base that also make the bike much more comfortable to ride. I aim at better than 60/40 rear/front loading and mostly achieve it but not by much.
The most critical measurement for correct fitting is the seat tube angle, range is from about 69 to 74 degrees, for seat fore/aft placement, most need around 71-72 degrees to get the most ergonomically correct position.
Changing one thing on a bike fit is like pulling on a strand of a spider web, every thing else changes. 15 mm shorter cranks means about 15 mm higher seat, about 7-8 mm more seat set back and a change in the handle bar position both vertically and horizontally. Baring other physical issues like hip issues I recommend the longest crank that can be spun at maximum rpm. Example: Max rpm on a short crank, use longer cranks till the max rpm reduces. Every one is build and functions differently. Stance width is an issue that affects many larger/wider build riders and women as well. Basically racing style bike frames are built for lightly built 60-70 kg riders, 80 kg is a big racing cyclist but 100 kg plus riders don't really fit well and trash rear wheels pretty quickly. Solutions for that as well.
@@dan2304 "Changing one thing on a bike fit is like pulling on a strand of a spider web, every thing else changes".
This is a comment I can definitely relate to!
@@podiumphysio657 Learned the hard way trying to fit bikes to riders. Gave up and measured the rides first then build the frames to suit. Retired now.
@@dan2304 So you get to ride "pro hours" now? ie whenever you want...
I'm 177, went from 172.5 to 170 and now 165mm. Feels nicer to ride after I got used to it.
My first ride yesterday felt quite comfortable!
@@podiumphysio657Shorter crank shines when you do longer rides. Last year to test, I had done a 200km ride with it after first doing few long rides with 172.5 and 170. This would be the main reason they are widely used in Tri Athlons.
Hello, I am very interested in your results. What is the relationship between shorter cranks and knee problems? Such as meniscus (patella?) problems. I didn't read anything about that. Thank you in advance and greetings from the Netherlands👍🚴♀️🇳🇱
Verwelkoming! I've not seen any data to correlate length of cranks with knee pain, however there is a reported relationship between the knee moving from out to in on the down stroke, and patello-femoral knee pain. Perhaps a longer lever allows greater amplitude of deviation? From what I've experienced and studied so far I would expect a shorter crank to help, rather than worsen any pain due to meniscus strain, but again I've not specifically looked into that topic.
@@podiumphysio657
Thank you for your reply. Maybe it is something to include in your observations while cycling. I personally put my saddle about 2.5 cm higher than the bike fitting indicates, because of my knees.
@@Martin-on2pp Yes there is an old dogma in bike fitting that a lower saddle leads to more patello-femoral pain due to more knee flexion and PF compression. But I think it has a lot to do with rider conditioning, cadence and terrain also.
What is considered a short crank 160? Whats the ideal length for height or inseam height? Basically is there a calculator for crankarms length?
Hey there. The point of this video and the several I have produced subsequently on the same subject is that the cycling industry builds bikes and provides components that suit the masses, often based on tradition and historical norms. I have presented evidence in this video that cranks as short as 145mm actually can be very effective. I am 193 cm tall and am generally offered 175mm cranks on any bike that I buy/ ride, however I have moved to the shortest possible cranks I can find from SRAM (160mm) and have found these to be much more comfortable and provide performance gains across a number of metrics.
I have not used and am not advocating any particular formula for crank length, however I recommend riders consider trying shorter cranks than the ones that come standard, and to not be afraid to go to a length that seems "unusually short". The evidence (and my experience) supports it!
I'm only 5'8" but I switched from 170s to 160s and I love it.
Were you happy right from the start or did it take a while to get used to? Any drawbacks?
@@podiumphysio657 Yes, much better immediately. I have a neuro deficit of my right hamstring due to a tumor on my spine, and my right hip is arthritic so as soon as I shortened the stroke there was relief. I believe my cadence is higher as well, which transfers more load to the cardio system rather than the muscular so that seems to help as well. I could even go to 155s, I think.
What are the sizes of the chainrings and cassettes on your bikes?
Hey there. I’m traveling overseas at the moment and don’t have my bikes with me to check, however I know my Emonda has a 52/36 chainring and a 28/ 11 cassette. And I think the Tarmac has a 48/ 35 chainring and 36/ 10 cassette . Hope that helps!
I'm 175cm with 82cm inseam. I use 170mm cranks and they feel good. Maybe it's because I train legs and deep squat alot and my mobility is really good.
It will certainly help if you are strong with good flexibility. However I've also now seen some very interesting performance benefits in going to shorter cranks, regardless of those two parameters.
Did Jim show you how and where the power data was collected in his test?
So this conference was 5 years ago, and I dont recall the exact methodology being discussed, however I've found one of the papers on line and it describes the method as:
"Maximal cycling power was measured using the inertial load method (Martinetal.1997), which determines the torque and power delivered to an ergometer flywheel across a range of pedaling rates."
I have 175mm on my road bike and 170 on my tri bike, honestly I think it makes almost no difference and can't tell any benefit other than when on the tri bars it is a bit nicer on my hip flexors because of opening the hip angle.
Yes the time trial position is where this will be most noticeable. I had 172.5 on a previous bike and I did not notice any difference at all (only 25mm difference though)
What would be the difference between shorter cranks vs lowering your saddle ?
Sure. Lowering the saddle will increase my torso angle (good for my hips, worse for aerodynamics), but would also result in a higher relative knee rise at the top of the pedal stroke (bad for me), and would potentially increase the knee flexion at bottom dead centre which probably is not ideal in general also. This may increase patello-femoral compression and possibly irritate that joint, and perhaps move you out of the quads/ glutes force production sweet spot.
What is your inseam length? I am on a 58 cm cannondale road bike and 178 cm height 91.5 cm inseam and 175 cm cranks. So trying to figure out what’s best for me. Thanks. Dale.
Hey Dale. I've never taken much note of my inseam length and have never recorded it for anyone that I've done a bike fit for.
The whole point of this video is to show that going to significantly shorter cranks has multiple benefits and no discernible downside.
As a six foot four rider I changed from 175 to 160mm cranks, and 6 months into the experiment I've been very pleased with the results.
If you are 178 cm tall I'd suggest 175mm cranks are way too long.
@@podiumphysio657 My intuition says even though I am not tall for my inseam length of 91.5 it may feel different to get on shorter cranks.Maybe I will have to shorten it to try? Waiting for your experiment?
@@daleschrader1946 Dale - Yes it feels a little different. In my case I can say it definitely feels better. Remember though that my primary reason for changing to shorter cranks was to look after my arthritic hips. Reducing pain was my primary concern and everything else was a bonus.
I've made 6 videos on the subject of shorter cranks, looking at many different elements - bike fit/ FTP/ sprint power etc. These are all available on my youtube channel.
After 6 months I can say I am very happy with shorter cranks and have no intention of going back to 175s (other than to conduct more experiments). All of my regular training and competitions will be on 160s.
About 3 1/2 years ago after seeing a Cam Nicholas video about cranks
I took the plunge and went from 172 to 165. Crank length. I'm 165 cm in height.
I use a crank based power metre, would someone know if the wattage is affected by the shorter length.
Is there any data about power output from shorter cranks?
Hey did you watch the whole video? There is a specific discussion on this topic.
I have some further information on power output here. ua-cam.com/video/P0qO6Wza58w/v-deo.html
@@podiumphysio657 thanks I guess I didn't cover the whole video.
I'm a convert already. All the best
@@lilth501 No problem. I'll be making a few further videos in the coming weeks on the same subject. Keep an eye out!
Surprised you didn't mention greater ground clearance which would mean continued pedaling around tighter corners.
Yep that would be something else to note for sure
This from one study without any links provided?
I don’t need one because if this was the case ..that shortish cranks provide all benefits mentioned in this video then the pro peloton would be stacked with them. That is not the case
Here is the study. I dont have access to the full paper. I was at the ISCO conference in 2018 where Jim presented these findings as part of his overall workshop.
pubmed.ncbi.nlm.nih.gov/9372489/#:~:text=Inertial%2Dload%20method%20determines%20maximal%20cycling%20power%20in%20a%20single%20exercise%20bout
I’m 174cm and converted to 165mm cranks last year and will never ever look back, so many pros, only con was the cost of changing all my bikes over…
So a win for you and a win for component sales!
@@podiumphysio657 everything you said is true. Aero benefit (taller saddle height means head is lower), less hip impingement, knees don’t hit your stomach when in the drops, higher pedal height through fast comers, no loss in overall top end power (can still make 1150W with 165 as I did with 170 or 172.5), higher natural overall cadence (especially important for climbing steep hills, it’s like having another gear added without changing the cassette essentially), some weight saving from long cranks to shorter cranks (every gram counts!) and lastly overall less muscle fatigue on endurance rides of which I did several 10hr efforts last year. I’m 45 so as you get older your body will tank you for it!
The only small con may be that the position is slightly more aggressive because your saddle height rises by the amount of mm you reduce your crank length by, this in turn lowers your stack height relative to your saddle so your torso angle changes. I had to make small adjustments to my front end to compensate for this for more comfort (-10* to -6* stem angle was enough for me to alleviate neck and trapezoidal pain on >4hr rides)
@@Lillee1969 I'm yet to delve into top end power. Definitely looking forward to checking data on that!
@@podiumphysio657 Legend has it that Sir Chris Hoy ran 165mm cranks so I am sure he isn't short or any power!
@@Lillee1969 I saw a video of him squatting 190 kg sometime in the last 12 months or so. His post retirement personal best!
Very insightful and although the empirical knowledge supports shorter cranks although mainstream suppliers are not providing anything near this knowledge. Btw you don’t need anymore power….
Thanks Peter. Stay tuned for the updates once the shorter cranks get installed on my Tarmac!
Looking forward to your update. Been thinking of swapping 175 to 165.
Have collected the bike today and am hoping to get a post up on the weekend!
I'm 4'11 and was riding 160mm. Crank calculator siad I should ride 145mm. I felt like that was to big of jump. About a week ago I put some 155mm cranks on my SL8. I immediately noticed a huge reduction in hip pain. I think it will completely disappear. I don't think I can go to a shorter crank because my knees might hit my chest from the bike being so low at the front. My power numbers are very low. This year my plan is to cycle more and increase my power numbers.
Did you increase your saddle height after changing the crank arm?
Whenever you shorten crank length, you need to raise your saddle. For example, going from 175mm to 155mm would need a seat post increase of 20mm
Hi Kim, Did you raise your saddle the 5mm? Also you can raise your stem (or flip it to give you height). This should help (reduce) gut/chest strike. You could also put your cleats as far back as they will go to aid stability and power transfer. When you do this, lower your saddle by the amount you slide the cleats back. thanks, mark
I am 5'4" 164cm with inseam 69cm , i used the on line bikefaff the answer i got was 140mm . As luck would happen i found 140mm cranks from a folding bike . Swapped them over and revolutionised my biking . As far as i am concerned the best move i ever made . Only you might need to use a slightly lower gear . I moved from 165mm to 140mm about 15% shorter, i think i need a 15%lower gear which you would need to turn the cranks 15% faster for all being equal? I couldn't care less for performance or marginal gains , but comfort is everything for me . 140mm for me never giing back .
@@mrwhiteshorts no, actually lowered it a bit. To me it feels more comfortable. Maybe I've had my saddle a little to high. I would get pain on the inside of my lower thigh. I also moved my cleats all the way back. My other bikes still have 160 cranks and I haven't lowered my seat on those. But I'm no longer experiencing that pain. It also could just be pain from cycling more
So why the currently champion of the Tour of France measuring only 174 cm is using 172,5?
Probably hasnt seen my video yet 😎
Not that long ago all road bikes were using 19mm tyres. Wider tyres were a "crazy" idea. That was the norm.
Now most road bikes are on 28mm, and 19mm is "crazy"!
Don't change any bike fit positions straight away.
I also believe based on you body height going down
to 160mm may well be a step too far, seeing that
your very tall try 165mm first. I am 5ft 6 inch's and
I run a 165mm. I know of guys your height would
have been running 180mm back in the day. Well
let us all see what happens, good luck...
Cheers. The 160s are already on the bike so I'm committed to trialling them at least. If it doesnt work out I'll try a different length. So far (one week in) I have not noticed any downsides.
Would like to see a comparison of power vs heart rate for a 40 K time trail, to really see if there are any advantages, that would be telling... Maximal power is not really that relevant to most riders, but if you can complete a 40 K time trail at the same average power, but with a lower heart rate, that could be meaningful (under similar, rested, conditions) showing an increase in efficiency. These claims of improved aerodynamics never appear to mention that one will have to raise their saddle with the shorter cranks, which will increase total frontal area, hmmm...
Agree, but doesnt higher cadence equate to a higher h/r for most normal humans
Higher heart rate (under the same given conditions, temperature, rest, fueling, etc) means the body is working harder, so if it requires a higher HR to produce the same power, it is then less efficient. Dylan Johnson has a good video on crank length, which examines the actual scientific testing of such, rather than just theories. So far, the available testing, shows no significant differences using shorter cranks, no drawbacks either. As there are no drawbacks, if one finds more comfort with shorter cranks, then by all means one should likely go for it, but so far the science does not show performance benefits in real world testing. It appears that the body is pretty adaptable to different crank lengths, to a point at least. As crank replacement is very expensive, it is important to really find out if there are performance advantages before recommending such.@@paulwebster4499
I like the idea of power vs heart rate assessment on a longer ride, however I might start with something a little shorter first. I had my first ride with the new cranks yesterday and have raised the saddle 15 mm but not the bars. I have the Specialized 6 degs proprietary stem, at the highest level. It cant be flipped so I'm going to explore keeping the bars as is before I try to find a stem which allows me to lift the bars.
I felt pretty comfortable yesterday, but unfortunately my left POWRlink pedal signal dropped out mid ride so the power data was corrupted.
I used my wife's bike with 165mm cranks for 2 years and i have to say they never felt right. I rode roughly 32km per day on that bike until i was able to replace my own that had 172,5mm. I'd like to see repeatable proof that shows it is better, but i don't think it's for me personally.
I'm planning to put up a bunch of data comparisons over the coming weeks...
Maybe for your own experiment you need to try the shorter cranks on your own bike?
@@podiumphysio657 i had 165 on my fixed gear but replaced those with 172.5 spares i had laying around as soon as i could. But for my roadbike i don't have shorter cranks at my disposal, which is where the value is in comparing them. So i'll patiently wait for your findings haha
@ Updates are on their way...
I found this equation worked for me: Crank length (mm) = 5.48 x Inside Leg length (inches).
Being only 169cm short with 29" ~ 29.5" inside leg, this eqn led me to 160mm cranks, which I find very efficient and providing all the benefits you listed. Spinning easier, too.
While Tom Pidcock (about same height as me) was being interviewed by Matt Stephens recently, he mentioned that Team Ineos were putting him on 165cm cranks for his road bike (standard Shimano size) and 160cm cranks (not a std Shimano size) for the TT bike from 2024.
Based the above eqn, I'd expect 160cm cranks may be too short to be efficient for the presenter of this video. Let's see.....
I think having a formula like this can be a good place to start, however there are always nuances for each individual cyclist that may require a deviation from the mathematical result.
The actual problem is availability.I am using 165s on my roady but you just try to find some.They are not commonly available to purchase.P.I.T.A😢
Yes I was lucky. When I approached my LBS they went online to their supplier and said there were 2 sets of 160s in stock so I grabbed one pair straight away.
A PHD in crankology ? 😂😆🤪
I have a Masters. I think I'm done with university now!
lol , i have the distinction of having been thrown out of kindergarten .
true story . 😂
I found that your cranks should be 18 to 19% of your leg length.
There are various formulae out there as a starting point, but I'll always check the angles created, do some functional tests and check with the rider about how it feels.
I have tried them since 1993, first I tried 130mm and I ended up using 150mm for all around cycling and 155mm for climbing, I'm never going back to long cranks, back in 1996 at the track in Calgary everyone thought I went nuts hahahha.
@@paulrobinson4987 If we didnt test our own hypothesis we would never advance...
and you didn't even test them in the vid wtf
yup. It is all coming up...
The shorter the wheelbase the shorter the crank-arm, The longer the wheelbase the longer the crank-arm. A long wheelbase bike, 170 crank-arm. A short wheelbase bike, 165mm crank-arm. A short wheelbase bike with a long crank-arm would increase the risk of your toe rubbing against the front tire when you’re turning the bike into a tight corner. A short wheelbase bike would typically be used for Circuit Racing on traffic-free roads or a closed road circuit such as a town or city centre. Kellogg’s city centre cycling 1983 part 1 - UA-cam. Reynolds 531, Steel is Real.
The Emonda in the video has a short wheelbase (H2 geometry I think), 175mm cranks and I have several cm of toe overlap on the front wheel. I've never struck the wheel with my toe racing, training or commuting. I have only ever noted contact when stopped at traffic lights.
It would take less power to turn the 175 crank than a 145. I'm not sure that chart is accurate. That's basic physics. If the force is applied closer to the object the torque is smaller than if the same amount of force is applied further from the object. I believe that chart is saying it takes more power to turn the crank when they are smaller. I personally ride 175mm on both my road bike and gravel bike. I've tried shorter cranks and I personally wasn't a fan.
The study is saying that the rider can produce more power using the shorter cranks, not that it requires less power.
If it was that easy, why wouldnt grand tour riders who were nearly there (Landa yates bros etc) just fit 165mm and beat Pog on his 170mms and Vina on his 172.5🤔
Probably in the same way top riders all rode 23mm tyres, now most ride 25mm most ride 28mm and some 30mm .things move on from what used to be .
@@robduncan599 yes 28mm tyres are better
when paired to the correct size internal rims. Still doesn't answer my question, Pog 170 vina 172.5 surely someone who is nearly on the podium would just switch to 165 and win the Tour. Fads in cycling come and go. I do agree that it has lots of grounds in a iron man when you can use 165 to lower the saddle and higher the stem to get into the latest aero (no gap between hands and head) position
@@paulwebster4499 I am at best a casual rider . Small 69cm inseam, all my life have been fobbed off with 170mm cranks on the odd occasion get 165mm. Knowing i needed much shorter for my short legs . I am 61 years old have been battling this all my life ,for me this is not a fad .
I recently found a solution ,Knowing i needed 155mm or so went on line bikefaff crank length calculator and found out 69cm inseam = 140mm cranks! Could this be possible 🤔? After 30 odd years on ,off mostly off cycling,me and a pal built up a bike of many bits, but cranks was going to be the sticking point, could i find 155mm cranks or is 140mm actually a thing ?
Answer, my friend has a old ARGOS challenge folding bike in a shed, low and behold 140mm cranks. Is it possible? Yes we built the bike up will they work ? Will they be to short ? I can tell you this is a whole new experience for me . A revolation , not only do they work the are absolutely spot on ! They are heavy and not in any way sport , but i searched all my life now finally found the solution . What is even more surprising is my friend is much more sporty does the strava thing and all that ,is 6 feet and a large size bike tried my x small bike with 140mm cranks his comment was they are ok ,not ridiculous small even for him .
So we don't see small ,XS or even XXS bikes with short cranks to match in bike shops , mostly get 170mm take it or leave it ? That might start to change, hopefully?
I'm sure there is a huge degree of individual preference and learned adaptation to sub-optimal set ups. For me I have moderate osteoarthritis in both hips, and not a single fast twitch fibre in my body, so I think that going to shorter cranks is likely to help me in a few different ways. If I am more comfortable, that is a win. If my performance remains the same or improves a little I'd be thrilled.