The Theory of Oval Chain Rings | ROTOR Factory Tour
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- Опубліковано 18 жов 2019
- Oval chainrings caused the collective eyebrows of the cycling community to be raised when they were first pioneered by ROTOR, but have firmly entrenched themselves in the pro peloton and won some of the biggest bike races in the world. ROTOR invited us out to take a look at how they make their Q RINGS and explore the theory behind them.
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Leave us a comment below! - Спорт
Am I the only one who thinks apart from the accent, he really didn’t answer the questions, it’s almost like he is saying something completely unrelated. 🤔
Yea kinda, they should have let him answer the questions in native language and then translate with sub...... Or the answer was simply planned to avoid some point eheh
Yes, it had the ring of authentic bollocks, didn't it...? (completely oval)
Thinking the same. Funny how he noted that they last forever and he can't sell new ones. Go carbon. That will solve your problem.
You must be new here expecting them to actually adress the topic in a substantial manner.
Geoff Goldplum you must be new to the concept of “answering a question” 🤔
What is hard to understand here? Moving chainring back at downward stroke rotation increases leverage and thus torque. It’s like longer crank effect without longer crank.
Ive had an oval on my mountain bike for over a year now and i love it.
Oval chainrings increase your effective cadence window. What that means is that you can use the most effective portion of the stroke to "energize" the system (inertia) and minimize the needs to use weak portions that can lead to early fatigue. We already naturally seek that balance when we shift but the gaps are not consistent and the gaps required change depending on how close you get to your limits and how much inertia is stored (and resisted) under various conditions (depending on velocity and whether you're descending, ascending and so forth). The interesting thing is that highly aerodynamic configurations also extend your cadence window by reducing resistance that opposes the inertia. IOW, the weak portion of your stroke is given a bit of a rest in addition to finding your optimal cadence (that varies according to conditions.
I know it's hard to understand but that's mainly because of how we teach "power production" in a human as though humans are warm-blooded electric motors or perhaps 2 cylinder engines. Your muscles are not pistons. Your muscle cells are like pistons, combustion chambers and fuel refiners and are unevenly distributed compared to an electric motor or an internal combustion engine.
If you find that you do better in certain conditions by paying close attention to your cassette an chainring combinations and get good results by changing, you should try oval chainrings to see how this helps with smoother pedaling under varied conditions. Put another way, using a Kickr or whatever is not going to help you understand the need to shift and how to figure out cassette combinations unless you deliberately test high and low inertia (which would be comparing "200 watts" with a lot of energy stored in the flywheel pedaling in your biggest gear to the same power with minimal energy stored by using your easiest climbing gear).
Perhaps Jan Ullrich could have beaten Lance Armstrong if his team had done research in to non-round chainrings to solve his problem with melting down when under late attack from the likes of Lance Armstrong. There's probably a consistent correlation between rider weight and how susceptible a rider is to attacks versus being able to ride their own pace in a time trial. It's not just about power to weight ratio because when you have to ramp up your power suddenly the spike in force scales with weight and looking only at power doesn't explain how this affects fatigue. This also explains why Chris Froome is able to show such resilience under pressure while coming so close to his limits without easily being triggered by pressures to overcook himself.
9:30 - will an oval chainring make me able to push 500 watts whilst casually chatting away like I'm on a coffee ride??
This ain't nothing. I use triangle-shaped chain rings made of Illuminatium.
The rest of the world are using round chainring made of chinesium
@@dindinduckduck Peter Sagan uses UNOBTANIUM. If you ain't King Peter, you can't get it....
I love square chainrings
All the -iums.God help me.
DI why
Chris flexing these watts during the bike fit! Spotted!
I first had an Oval chainring back in 1990-91 on a MTB. Been tempted to try them again.
If round chainrings are good enough for Peter Sagan they're good enough for me.
Round chain rings good enough? Wiggo and Froomy - Hold our beers!!
bad joke aside this video ADVERT does nothing to convince me and i use Qrings - that said I came back to road bikes after 20 years off 3 years back and the bike happened to have Q’s fitted - what’s sold me was my new road bike came with duraace and on my tester circuit i was slower and less power on rounds - second on my 1x fat bike in top gear flat out (yes makes no sense) it smoothed out the whup whup mashing once i moved to a oval
So works for me - still to try the soy metrics however
David Pinnington Maybe gave you a psychological boost, because you believed in the technology. Transformed it to physical improvement. If it works for you, go with it!
Oh yeah I bet you don't pedal like Peter fella
I’m not Peter Sagan so I’ll take all the help I can get.
Yeah 6 tours won with oval rings
Noticed that one of those Rotor guys was handily mixing it up in the sprint with an ex-pro too. Pretty handy office sprinter! Maybe they lunchtime ride to power everyday!
I think Irene explained it very well!
Very interesting. I had a special Trek touring bike back in the eighties with an elliptical chain ring. It didn't work for me as I had decades of circular rings. I was amazed to see Froomie riding one. Back in the criterium days, it was spin to win. I saw Armstrong do it in his day and Froomie doing it now. Amazing the tech involved with cycling today.
An amazing scientific figures video!
I have been using Oval ChainRinge for 3 years, and I really love it.
Now, thanks to you guys, you brought a bit more sense!
In the 80s my dad bought a 'mtb' from Halfords (apollo Vesuvius) with a suntour ovaltech chainring set. It still is going and is a pleasant bike to ride
Nice to see biopace making a comeback. I still have some on some of my bikes. As always, cycling trends going around in circles.
Or going around in ovals ;)
Please, please, please can GCN or ANYONE just knock on the door of a physics or engineering professor and get an answer on these things. Where are the forces acting? What would an extreme elliptic feel like? What happens of you put an elliptic on 90 degrees rotated from where it should be.
Stop talking to manufacturers, for God’s sake. It’s like asking CeramicSpeed I’d they have any innovations in drivetrain technology 😜😜😜
It's easier for your legs to rotate the cranks because you are pushing more perpendicularly and also more in line with gravity, and your kneecaps don't rotate as much. At least that's my theory, idk if it actually works.
Hi Albert, Thanks for your message. We are a team of engineers and we firmly believe in the oval chainring concept for reduced knee strain.
There are less accelerations and decelerations because knee speed remains more constant. In the weak zone you need to apply more force with a round ring than with an oval ring because the diameter of the Q RINGS® becomes smaller. The resulting force representing the tension suffered by the knee is therefore less with Q RINGS® than with round chainrings.
Please see more info at the following link:
rotorbike.com/wp-content/uploads/2018/12/ROTOR-Biomechanics-doble-page.pdf
Thanks
ROTOR Team
When the oval shaped ring is rotating through the most vertical position it would pull/push the chain faster for at a given rotation rate but require more torque than when its more horizontal. For the same rotation it would require less power when closer to horizontal but move the chain slightly slower. Each gear tooth is basically a lever with the fulcrum placed at the center of the gear. Changing how close the tooth/teeth are to the center of the ring that are applying force to the chain basically changes the gear ratio. Its like running two different rings at once. One for the part of your pedal stroke where your comfortable pushing the hardest and one for the when you can not produce as much force.
@@ROTORbikeComponents I can say for sure, 100% for sure, that using an oval ring has helped save my knees which will need to be replaced one day. However the oval ring is extending their natural life as long as possible. I live in Andorra where the mountains are steep and I am now climbing better than I have in the last almost 10 years (I am 61yrs old). The stress and tiredness is reduced. (Though for full disclosure I use Absolute Black)
@@TheFixerOfAll Nicely explained!
They're definitely not cut square for waste minimization, as that would result in more waste than cutting compact ellipses. They're almost definitely cut square for fixturing purposes during the milling step.
Chris looks leaner after cracking the Zwift Academy.... Power to weight ratio improved?
Chris asked such good questions during that interview 👌👌, excellent info my man. Felling an itch in my wallet now 😬😬
See the chainring spinning makes me uncomfortable
Raditya - yes - it looks like the chain ring is loose
Really enjoyed this Vid. Thanks to ROTOR. insightful questions . Good information shared. Not a massive GCN fan , but I do enjoy Chris. Perhaps he goes a little deeper. Anyway . Well done and thanks
Wow!
This is so cool and fascinating! Now I know how these super cool oval chainrings are made and the theory behind it.
Great to understand more of Rotor, theory and practice. Oval v. Round, there's an unexpected consideration for the next upgrade. Sunny & dry, should have tried the 24hr over there Chris
Unreal how deep the tech goes...
Awesome
I've used Q-rings consistently since 2006 - I obviously prefer them, but have always wondered if it is more placebo effect or an actual benefit (and I use a PowerTap hub, so my watts measurement is not affected by the variance in cadence)
Good Review. I started with a lot of skepticism but this is actually a lot more interesting than I expected.
Thanks Grunchy
I picked up a set of O rings in 2008-09, got used to them and loved them. My problem was they weren't available for the 2 other bikes I was also regularly using and going back and forth was awkward. I haven't used them in years now but can see a day soon (reason for a new bike?) when I can get a one-by like that Canyon that I can use a range of tires with and only pay for one chainring. Perfect for that really because oval rings can cause front shifting problems.
Speaking to my club mates I've found that the really good climbers haven't found that they make much of a difference, whereas the sprinters (like myself) absolutely love them for climbing.
My conclusion is that they help you at the top of the pedal stroke, something climbers naturally don't need any help with.
ummm...big ring is 10%oval small ring is 6%oval so climbing they have less effect on pedal stroke
I have tried them and hated them and they actually negatively impacted my climbing. My wife loved them and they seemed to help her. The difference? I have a smooth pedal at rock, and she is punchier with her pedal
stroke. I think that is what it comes down to.
I always hear this too but when you look at the very few people left in the World Tour using them (or has used them).. it's climbers
So they help a certain type of rider. Ovals would help a sprinter more for uphills
You spin easier, faster on ovals. It's a simple, use your power ring big when your naturally adapted too, when at the bottom, they perfectly allow the lesser part of the leg to more easily bring it around, not rocket science. They feel better, end of story.
I remember hearing about Oval Chain Rings like, 20 years ago. Always seemed like a cool concept.
Had something similar on a Nishiki Linear years ago and it was great. Nimble bike, nothing high end but I put a lot of miles on that bike in college.
Beside oval theory Rotor cranksets are just superb quality, looks cool, it is fully customizable and keeps factory in EU... one of my favorite bike brands :)
A special thanks to GCN. I watched the video and sent an email Rotor about the possibility of going for a lunch time ride with them and they said YES. I am from New Zealand and on holiday in Spain for a holiday. This is a fantastic opportunity. I will let you know how get on. Thank you GCN!!!
Happy riding Pete!
See you tomorrow!
Not into power or oval, but that lady at Rotor really knows her stuff!
I'd love to see GCN (or GCN Tech) do a comparison of Q Rings alongside Shimano Biopace and Ossymetric rings to see what difference there really is in the pedal stroke. Are they all the same idea, or are there significant differences?
Digging Spanish lunch breaks ☀️👍
@3:05, that appears to be the Cervelo S5 in 2015 Qhubeka graphics.
Look at that amazingly beautiful silver aeroad....
(I'm not at all biased).
No need to get all excited about the recycling they do.
Every single manufacturer who works with metal has been doing that for ever.
I’ve never really thought about it for road, but I can get up steep techy climbs on my mountain bike better now without such leg stalling at the top of each stroke when it gets slow with max power. Everyone knows the feeling of struggling to get up a hill with each crank almost stalling just trying to get over the top of the stroke to the “nice down bit” where you have the power and weight of your body behind it and can pump that half a stroke before the next near-stall. Many variables may be at play, and it may not seem like night and day, but if I can physically make it up stuff I’d have to get off, there’s definitely something there. Plus the common sense I can’t put the same amount of force in at all crank angles. Plus me not telling my mates I’d got one and them thinking my climbing had improved and getting some new surprise PBs on Strava. It’s not making more power, just making the hard bit easier (narrow bit of chainring) and the easy bit harder (wider bit) and still the same gearing for one whole revolution (number of teeth). Simple Newtonian physics of levers and force. P.S. that isn’t clipped in, so that may make a smaller difference if I could “pull” my way round the weak parts of the stroke, but I still think it would be some help. Also if you have a faster cadence than me I guess that might make it not as obvious either as the flywheel effect of your legs may help it zip on round. But I can’t see any arguments for it not making sense or working, just how subtle the effect is due to the other variables.
How long is their lunch break?!
The Spanish are known for having a 2h lunch break
As a spanish I can tell you that our lunch breaks run as long as many anglosaxons tradition of talking disrespectful crap about other cultures without having the slight idea of what they are talking about, quite long. On the other hand is easy to fall into long breaks when you eat real food. I hope this answer may be of any help for you
Alberto fernandez rodriguez what was all this passive aggressive crap for?
long enough.
@@desofan who pissed in your cornflakes?
Great video, thanks Chris, nice place, lunchtime rides?!........don’t think my boss is gonna go for that?.
P.s. I have a 1992 Raleigh hybrid with oval Shimano rings?, how about a video of the full history of oval rings?....
I think Shimano did something similar in the '80's. Biopace name rings a bell.
Biopace had the orientation completely in the opposite setting (i.e. wrong), with the most torque (smallest radius) in the region of most force (down stroke).
"Shimano created their non-round Biopace chainrings with a completely different orientation of the biggest radius of the oval. Their ring orientation has since been widely accepted as being fundamentally wrong. Instead of positioning it in power zone - which is slightly below the level of the crank - they clocked it to the dead zone where human physiology generates least power. The result was that in power zone pedalling was too easy and in dead zone too hard, causing knee pain and lumpy pedalling cadence. Exactly opposite to how it should be."
absoluteblack.cc/why-oval/
@@kalijasin I remember moving the bi-pace chainrings around and trying them in different position on the crankset I believe that was 1988!
@@kalijasin And yet, BioPace had its devotees and positive press. If that can happen with an exactly-wrong setup, the oval advantage (if any) must be trivial. Human physiology is quite adaptable.
I tried Biopace in the 80' and spinning felt so weired. I changed back to round ones.
Wow, I wasn't expecting the rabbit hole to go so deep.
I reckon that with oval chain rings and L-shaped crank arms, I should be taking all my local KOMs next year. Thank you for bringing this to my attention.
Got a biopace ring set in use still here!
Same, it's so hard to tell the difference but I enjoy it
I recall some people complaining about knee pain after using Shimano Biopace oval chainring back in the days.
Makes me want to paint my Aeroad that cool silver color.
after the lunch ride you never spoke about the handling, gearing, hydro, and oval chainring feel.... ie: how you liked the bike?
Not sure about the chainring, but I do like that bike!
The most remarkable thing about this is how he managed to make it to October, 2019 having not ridden a hydraulic group set.
He meant the derailleur being hydraulically actuated, not the brakes. If that's already what you meant, then I guess I'm surprised it's that common, because I certainly have never even seen a hydraulic groupset.
@@EnjoiEmerica11 Thank you
If they actually worked as advertised, every pro cycler woud be using them....good improvements like narrow/wide chainrings actually have a noticable improvement, I am not convinced this is an improvement. Pedal bikes are one of the most refined inventions, and is difficult to find any sizeable, measureable improvements to design. Lighter components and materials have helped recently.....but the mechanics of cycling still remains much the same after 100 years. Goes to show how great of an invention a bicycle was!
Interesting technology but one thought comes to mind. When the rider gets up out of the seat say on a hill does the power curve not shift and thus is this compensatable either automatically or manually?
yes and when you pedal standing up you notice that this is not optimal and i don't think this can be compensated easily but it is not too disturbing and i guess the argument is that the percentage of time you ride standing is small.
@@alpw1234 Given the preponderance of electronics entering the bike would I would have thought some for of cam changeover could be adapted much like the BMW 1250GS [yes I know a cycle is much lighter but the idea is there]
The lunch brake ride.🤣
GCN Espana having a coffee there, eh?
Love watching manufacturing videos, right up my street. Also, I love even more that everything is recycled. Makes me really warm to a brand when I know they have minimal waste.
Probably recycle because they get paid for the scrap. A financial decision.
Ohh saw your Rotor ride on strava thats why..
Good, Good!
Nice ROTOЯ polo shirt.
Currently building up a bike with my first oval chainring, but from Absolute Black. Tho I'm waiting on a Rotor 12 speed cassette that's backordered :^(
Great video!! Putting force into the crank arm is nothing like a freestyle swimmers stroke, I don't get the analogy. My main issue with oval chain rings is how many watts are lost through the rear derailleurs constant movement during the rotation V watts gained by mechanical advantage? I have always doubted that the theoretical isn't equal to the reality. anyway they look cool and that counts!
I still have a Shimano Biopace bike but I rotated the chainring because I couldn't understand why they had the largest diameter at the weakest part of the stroke - crazy!
some argue it's solutionism. Francis Cade has a video where they mention the industry creates solutions to address symptoms of bad fit: dead spots maybe caused from overreaching/confinement. I had rotors from a bike I bought second hand. I changed my big ring and kept the little one oval. For some reason I just prefer it that way.
They're good on mt bike inner rings, you don't break loose as often by ovrer-torquing the downstroke.
Ok on double road inners, there it evens climbing pump as well to roll better, shifting is why to not bother for most riders.
Ymmv 🍺
I think Irene missed out on the lunch ride that day :-D
She was in front of Chris.
I didn't see any theory? Got any theoretical basis to an optimal shape or any experimental data?
Hi Thok,
Q RINGS® are oval chainrings designed to increase performance of cyclists by reducing the impact of dead spots in the pedal
rotation. Q RINGS® become larger around the strong zones and smaller around the weak zones. Therefore time spent in the strong zones is longer, while time spent in the weak zones is shorter.
Everyone’s pedaling style is different, so weak and strong zones vary by a quantity of degrees from person to person. The ability to adjust the position of chainring orientation to the crank via OCP (Optimum Chainring Position) is the key to fit each unique user’s needs.
Please see more info at the following link:
rotorbike.com/wp-content/uploads/2018/12/ROTOR-Biomechanics-doble-page.pdf
Thanks,
ROTOR Team
@@ROTORbikeComponents You didn't actually answer the question. Putting aside marketing copy, have you published data proving that this product increases performance and with approximate performance benefits across a range of power outputs?
@@magnemmar4869 Second that - It sounds like a resonable hypothesis from Rotor, but unless they can back it up with data it does not convince the scientificly inclined.
I wonder to what degree, if any, the advantage of the eccentric chainring is negated by the two oscillations of the chain tensioner with each turn of the pedals (losses due to friction in chain tensioner bearings as it swivels back and forth, and heat dissipated by its spring, and the chain itself bobbing up and down).
Wouldn’t it make sense to do the OCP/OCA test with round rings first?
Exactly my thought...that way you can see where in a normal pedal stroke you apply max force and adjust the angle of the oval positioning accordingly...
I’ve been using rotor for a very long time, it works perfectly for me. On My 2020 New bike I would love to have the new inspider powermeter. Hopefully more video’s on rotor.
Hi Stephane, Thanks for your positive feedback, ROTOR team
How many watts are used on the rd cage springs?
Are we going back in time? Didn't we do the Ovals back in the early 90's?
Ahh, Shimano Biopace - brings back memories 😁
lee mua nguyen the Shimano ones were 90 degrees out of the correct phase which means they made things worse... They were SO close to a great idea but messed up the details.
No they just never went away. Greg Lemond does not recommend them in his book. Steady cadence is no longer seems to be the focus for performance like it was in the 90s. Now it is power output. Meh. Not sure if oval chain rings help. Not to mention the problems of getting a front derailleur to work with them.
1890's would be closer to the mark.
I still have my 1988 Raleigh Montage with 3 ring oval crank albeit boxed for years awaiting restoration
notice the little text at the top right of the thumbnail that says "ad"? that's why there's no real exploration of any cons that may exist with the product .
These oval chain rings have been around for decades of bikes, for example the old steel frame 'Peugeot' road bikes...not all of course, but it's not a new concept ,which I would also like to try 👍
6:39 - and the sheets get shipped off to Apple to be shrunk down to make the Mac Pro front panel.
Question - does the oval ring cause extra wear for the jockey wheels and pulley?
I got 20k miles out of my rings and am still on the same Jockey wheels
It wears out clutches on mechs that have them
I've not had any significant issues, but my first bike didn't have a clutch and my second bike has been running oval only one season. The one thing I will say is the oval chainrings themselves wear super fast. If they have to shift, that is. One setup is 1x and it's fine so far, but it's from wolftooth I think. My road bike are older rotor Q's, 2x, and the 50T outer ring looked heavily worn after one season. And perfect downshifting at the front is near impossible to attain. You can get it to maybe 90%, 95% accuracy by the grace of the cycling Gods. But power or no power, at low cadence or high, there's always a chance of a chain drop.
@@Cal94 get a spacer for your front derailur between mount and it... it puts it in the correct position for ovals...
@@noahhalbfoster6892 so shift the derailleur back a bit basically? Vertical clearance I have enough of. But the derailleur is direct mount, so I can only go up, down, and back I suppose. Regardless, I have a new road bike, insufficient tools to get the old crankset off, and insufficient willpower to spend money to salvage the worn chainrings anyways, so it'll be someone else's problem when I sell it. The rest of the bike was such a pain in the ass that the odd chain drop was actually tolerable
We called this Bio-Pace in the 90's. I've used an oblong chainring on a buddies CX bike. (Absolute Black?) I felt less tied and was able to ride longer, but that is my due to my pedaling style. I don't spin. I mash. Either way, I still went faster on my own Gravel Bike due to better gear ratio.
If you see at 01:22 the previous device that he is talking about is clearly with eccentric chainring, and with cranks neither in opposite line! Something a lot more complicated/expensive with that box, but probably that actually provided a good mechanic advantage with a longer leverage when pushing and/or a shorter leverage when pulling. The oval ring I think that do not provide any mechanical advantage as the longer leverage that you have at the dead point (~0°)is compensated with the shorter leverage of the same measure that you have at the most advantageous angle (~90°).Result is that you have the same average power of a circular ring but with less "peaks" in the synusoid graph at cycloergometer. See www.allenati.it/analisi-della-pedalata
I think they well know this as they only speak about "less joints pain" as advantage.
P.S. Probably they discontinued the previous device also because th UCI rejected it. The rule says that traction movement must be circular. There was another device, named "Easy Crank" if I remember well, where the ring was circular and centered as usual but the crank was in two parts sliding one inside the other following an oval and eccentric cam fixed to the frame (one in each side). Also this disappeared probably because of the same UCI ban.
The goal of pedaling efficiently is to create an equal power output throughout the course of your pedal stroke, oval chainrings could make sense for people who haven’t trained themselves in XC or road biking, but for the well trained and pros, round chainrings are probably the way to go.
For extreme climbs on the edge of stalling oval will help everyone. Also if on the climb there is a root of something to suddenly demand more torque, it will prevent (decrease the chance) stalling when crank is vertical. In situation when torque from pedaling can make the wheel slip, oval can help by giving more even torque through whole rotation of the crank.
@6:38 The new Mac Pro inspiration.
Hmm, I have some Shimano biopace chainrings on old MTB that I bought in '90 or '91. What's different?
can these be used with fixies? :D
What about the water used in the cutting process, it is re-used?
The title of this video should be: ‘the making of...’.
I ride Q-Rings and I would like to know if the claimed 6% efficiency gain is correct, apart from the smoother ride qualities.
Maybe you can wear your scientific glasses in a next video and compare oval to round rings in terms of performance?
It's never been proven oval rings are anything more than placebo
Highly complex explanation “like a swimmer”
This was an excellent and informative video! Why have I not watched this before?
i’m on 11-28t 105 cassette, what oval teeth shoulf i go with, 52t or 50t or anything below..i’m on single 105 crank🙏🏼thanks guys!
50, if is possible 48
Shimano BioPace from the 1980's are not the same. The orientation was incorrect compared to modern oval rings. That's why they caused knee pain.
Old tech Biopace I have these on my old 1980s Road Bike
Its different, rotated 90 degrees,
Surely this just improves the pedaling with an up/down motion, rather than pedaling in circles how people are taught to pedal.
I think I saw a certain Oscar Pujol at a cafe stop at 16:11. Is he a secret Rotorian in disguise?
They made a similar video on the spanish channel, so that's why he was there. ua-cam.com/video/EGVkVnFcmXc/v-deo.html
Does the pumping up and down of the rear dera. when spinnig the oval create more wear on the rear dera.?
The movement is quite small, as you can see in the video. The chain always wraps exactly half the chainring, so the only variation is the distance from the rear cog and idler pulley to the contact points and that amounts to just a few milometers. I suppose it will eventually cause wear, but only after a long, long time. If you put a dollop of tri-flow between the cage and the derailleur body you should be fine.
I just wonder if the claimed power gain from these rings offsets the loss from working against the spring and clutch. The movement is quite significant, if it only moves 2mm (looks like more) for each revolution at 80rpm that's almost 10m per hour!
You need to dial into Mr Adam Hansen, he'll tell you a few things about Oval Chain Rings.
These rings are EXPENSIVE! I'm no Engineer nor an Orthopedist but LOGIC would dictate that Ovaloid CRs cause you to GRIND instead of SPIN, since the larger diameter of the ring is in the power phase: 1 o'clock to 5 o'clock position. This runs COUNTERINTUITIVE to what is being PREACHED today ... to "Spin, Spin, Spin". Seems Shimano had it right to begin with with their 80's/90's era 'Biopace' CRs which were OPPOSITE, placing the SMALLER diameter in the power phase: 1 o'clock to 5 o'clock position causing you to SPIN a bit faster in the power phase. For older riders or those with knee problems Biopace rings would be a much better bet than Rotor rings. Also Biopace rings could be a Secret Weapon in a Triathlon. Seems your legs would be fresher for the Run since you reduced your CR tooth count in power phase and increased you rest time in dead zone phase. I bet traction is better on climbs on gravel, dirt or mud with Biopace CRs. You can buy Biopace rings (mostly used) on Ebay in various sizes in 5 bolt from 26t - 53t in 74, 110 and 130 BCD. They are 1/10th the price of these WAY OVERPRICED rings too. I use them. They work GREAT and mesh fine with 10/11 sp. chains and have no issues with shifting the Front Derailleur.
Iv still got my shimano 600 group set with an oval ring from 92ish
Me to 😊
My 87 trek has them. They are nothing new. They seemed hard on the knees.
Hi Harold,
Thanks for your message. We firmly believe in the oval chainring concept for reduced knee strain. There are less accelerations and decelerations because knee speed remains more constant. In the weak zone you need to apply more force with a round ring than with an oval ring because the diameter of the Q RINGS® becomes smaller. The resulting force representing the tension suffered by the knee is therefore less with Q RINGS® than with round chainrings.
For more info please check our website: rotorbike.com/wp-content/uploads/2018/12/ROTOR-Biomechanics-doble-page.pdf
Thanks,
ROTOR Team
Hello! @@ROTORbikeComponents
I have a question regarding the variation of the knee speed.
As mentioned in the video by Irene (who seems to really know her stuff), it is important to calculate RPM multiple times during the pedalstroke because of the change in angular velocity (14:45). If now the angular velocity (speed of the pedalstroke) changes, how come the knee speed remains more constant, compared to round circular chainrings?
I just read a paper that might be helpful on this topic, "Effect of chainring ovality on joint power during cycling at
different workloads and cadences" by Strutzenberger et al. (2014), Figure 3 shows the varying cadences nicely.
I would really appreciate a solid answer to this, since I am interested in oval chainrings myself, partially because of experiencing knee pain.
Kind regards
Lukas
When doing the test, are you already in position 4? or does it tell you that you need to be in position 4 no matter what you have it on already
So, is it really better? Please make a test!
Minute 6:04 please use glove when take cookies for your own safety like you take hot cookies from oven. Overall video is great.
So, I'm guessing that the constant tugging on the chain caused by the oval ring causes pre-mature stretching of the chain?
I'm thinking that there is some validity for oval/asymmetric chainrings. Cycling is entrenched in tradition and anything new is usually frowned upon. I am going to try them and see what happens.
Oval rings is a old thing shimano did it first with "biopace" I still have my biopace cranks group Sante from the 80's
But Biopace chainrings aren't really oval.They're more like an unevenly drawn circle.