10 speed==>11 speed ring compatibility?

Brad Marcus

I went from a 10 speed tri bike to an 11 speed tri bike in the last year. When I made the switch, I pulled my Quarq PM off the old bike and put it onto the new bike without much thought. The only thing that needed to be done was a BB adapter since I was going from GXP to BB30. The new bike is also Di2...which I did not have prior. Strangely enough, I have had lots of shifting issues with the front rings since I've gotten the new bike. I've had 3 different mechanics try to figure it out, and aside from some ancillary issues, the issues keep cropping up after I'm told that it is re-adjusted properly.

Recently, my Quarq died. I pulled it off this week to send back to the company for repair/replacement, and on the back of the rings, it says "10-speed - not to be used on 11 -speed". Something clicked in my mind at this point that had not occurred to me before. Why would the rings be different on a 10 vs 11 speed? Is there a larger gap between the big ring and small ring on one? And, could this be what has been causing the shifting issues?

Appreciate any input here...Thanks!

Scott Alexander

I used my old 1st gen 10spd GXP quarq on both a BB30 road bike and my GXP tri bike.

I recently moved my BB30 road bike to 11spd w/ di2, and still used the GXP quarq and never had a problem.

I was told, it might not be "ideal", but it should have no problem working, and never did.

Dawn Cass

Brad, I am probably not the best one for this....or maybe I am. I as well got a new bike earlier this year...going from 10 speed, non DI2 to 11 speed DI2. LBS called quarq to make sure it could be moved and they said no problem...BB change was needed as you mention. Got the bike back and no problems....well for a few months. As you well know, it died a month before race day.

No idea if these two stories are telling us anything but will be interested in following to see others experience.

Mark Stahlkopf

Brad, I had the same issue. I replaced a 10 speed crank with an 11 speed. Apparently there is a slight difference in the spacing between chain rings which can cause shifting issues. I was able to fix this with some fine tuning of the front derailleur. It still doesn't shift as smoothly as the all 11 speed set up on my other bike.

Brad Marcus

Thanks for the insight here team. I've asked around a bit and as Mark mentions, there is a spacing difference on the 10speed vs 11speed. This may explain why I was shifting off the big ring on many occasions. Amazing to me that 3 separate bike shops couldn't figure this out, even when I told them I moved the PM from a 10sp to 11sp. Quarq tells me that if I swap chainrings, they do not need to re-calibrate my PM. I guess when I get the unit back from Quarq and re-install, I'll make the decision to swap the rings or not if shifting issues continue.

Thanks again for the help!

Mark Roberts

Look at some 11 speed chainrings by Praxis Works. Cold forged. Very stiff. They work on SRAM bolt pattern and shift perfectly. I put them on my old 10 sp Quarq when I went to 11 speed. When you install them, alternate tightening each bolt a little bit at a time and work each bolt to 10 NM. Even torque and the correct torque is important to ensure accuracy.