Oval chainrings; hard sprinting?
Moderator: robbosmans
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Alright
Have any of the sprinters on here (60kmph / 1200w+) done any massive leg outs on oval chain rings?
Any difference to round? Does the radial oscillation cause the chain to fling itself off at random, or does this not affect anything?
Have any of the sprinters on here (60kmph / 1200w+) done any massive leg outs on oval chain rings?
Any difference to round? Does the radial oscillation cause the chain to fling itself off at random, or does this not affect anything?
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I've been on Q-Rings for years and recently switched to Osymetrics... My biggest problem when sprinting out of low speed, while ignoring all technique, is the rear wheel skipping a couple of centimeters off the ground, the moment it lands the front wheel gets a lift, at this point the handlebars are usually pointed anywhere else than forwards due to me pulling on them, so the front end will go wherever the bars are pointing when the front wheel hits the ground, causing something very close to what motorcyclists call a "high sider". From behind probably looks a little something like wrestling an angry bull.
This is what I'd call putting everything your body has got and then some into the bike.
Have NEVER had a problem due to oval rings...
Technically speaking, I don't see how the individual chain links would see/feel any oscillating effects. And as for round vs q-rings your cadence speed thru the whole stroke has way more variation with round rings. So for speed oscillation round rings will "oscillate" with a greater frequency.
Pardon any and all faulty use of technical terms here, I'm a bike mechanic not a university graduate
This is what I'd call putting everything your body has got and then some into the bike.
Have NEVER had a problem due to oval rings...
Technically speaking, I don't see how the individual chain links would see/feel any oscillating effects. And as for round vs q-rings your cadence speed thru the whole stroke has way more variation with round rings. So for speed oscillation round rings will "oscillate" with a greater frequency.
Pardon any and all faulty use of technical terms here, I'm a bike mechanic not a university graduate
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Consider myself a sprinter. I've been using QRings for about 4yrs now.
I would say the 2 things I notice: 1) Make sure I'm in 1 higher gear and turning lower RPM before starting a sprint. Since I'm often in 11spd already, not much I can do about that one.
And 2) when you move forward/backwards, you are in essence changing the Index of the ring. Just like you can change the ring with Rotor to different holes, it determines what point the down stroke pressure/speed happens.
Thus, is you move up forward and your knees move ahead of the spindle (assume you use KOPS setup) you are actually changing the Index and it then hits the "Bottom" earlier.
Hence, why I put it in 1 higher gear if possible, because as you get out of the saddle, your knee/body position changes causing the speed of the pedal stroke to accelerate earlier through the bottom.
If that makes sense?
So it makes a slight difference, but not really much on speed/power/top-end etc..
I would say the 2 things I notice: 1) Make sure I'm in 1 higher gear and turning lower RPM before starting a sprint. Since I'm often in 11spd already, not much I can do about that one.
And 2) when you move forward/backwards, you are in essence changing the Index of the ring. Just like you can change the ring with Rotor to different holes, it determines what point the down stroke pressure/speed happens.
Thus, is you move up forward and your knees move ahead of the spindle (assume you use KOPS setup) you are actually changing the Index and it then hits the "Bottom" earlier.
Hence, why I put it in 1 higher gear if possible, because as you get out of the saddle, your knee/body position changes causing the speed of the pedal stroke to accelerate earlier through the bottom.
If that makes sense?
So it makes a slight difference, but not really much on speed/power/top-end etc..
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Good info, thanks.
So, neither of you have had any issue with really pushing hard, and the chain coming off?
So, neither of you have had any issue with really pushing hard, and the chain coming off?
The lower part of the chain is not tensioned even under hard efforts, so all it sees is the cadence.
I'm running Q-Rings and Dovals and have never had a chain come off at high cadence or otherwise.
I'm running Q-Rings and Dovals and have never had a chain come off at high cadence or otherwise.
Running Doval 53-36. Pos. 3.
Previously was on 53-39.
I feel like any speed above 60 kph comes with difficulty, maybe it's just the top end gearing disadvantage coming off a 53.
Hit 62.8 kph today , Might be imagining it but spinning the Doval up is much more difficult.
Example, some times you know 53x11 will be harder to turn so you sacrifice potential speed for cadence by down shifting the rear.
It feels like if I down shift the Doval which is already lacking the top end speed, I'll loose even more speed.
Other than the puzzling sprint performance, I like 'em!
Never thrown off a chain either.
Edit: To Doval users: Which position (2 or 4) would improve out of saddle sprints?
How would such a change impact the rest of the ride?
Previously was on 53-39.
I feel like any speed above 60 kph comes with difficulty, maybe it's just the top end gearing disadvantage coming off a 53.
Hit 62.8 kph today , Might be imagining it but spinning the Doval up is much more difficult.
Example, some times you know 53x11 will be harder to turn so you sacrifice potential speed for cadence by down shifting the rear.
It feels like if I down shift the Doval which is already lacking the top end speed, I'll loose even more speed.
Other than the puzzling sprint performance, I like 'em!
Never thrown off a chain either.
Edit: To Doval users: Which position (2 or 4) would improve out of saddle sprints?
How would such a change impact the rest of the ride?
I'm a Cat 2, ride Q-rings on all my bikes (other than the track bike), hit around 1400W for 5 sec in a sprint, regularly sprint at 70kph, have at least 65,000 km on Q-rings, and have never had the chain come off.
It's a non-issue.
It's a non-issue.
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EVO3 (sold) | 6.51kg
EVO4 | build thread coming soon
S5 Disc
SystemSix (sold) | 8.01kg
P5 Disc | heavy but fast
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+1 non-issue.
Osymetric user of 18mnths. Zero issues to report. I run the version with shift ramp/pins on big ring and they just work.
Osymetric user of 18mnths. Zero issues to report. I run the version with shift ramp/pins on big ring and they just work.
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Thanks a lot for all the responses.
Much appreciated.
Much appreciated.
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