So I just got a pair of Q-rings and they’re not a great fit. I’ve maxed out the front derailleur height and it looks like the shift from the small to big ring isn’t gonna be that great; however, I can live with it. What I can’t live with is the big ring just touching the very end of the front derailleur cage as the ‘biggest’ part of the ring comes around - we’re talking like 1-2mm here. Since I can’t move the derailleur up is there a way to move it back slightly so the derailleur cage clears it.
Btw - it’s an ultegra derailleur and braze on. Any tips appreciated. Thanks.
If raising the derailleur a little more would help, you could probably use a dremel tool to make that slot in the braze-on a little taller (or perhaps find a shop that will do it).
SRAM makes a front derailleur with two bolts for mounting to the braze-on tab. You sound like you are maxed out at the top, so the SRAM could be mounted higher (depending on the frame).
I have a few ideas that may work so give me a call if you wish 866-391-0493 or try one of the following:
As someone else suggested (assuming you are brave enough) you can dremel the slot in the braze-on to allow you to raise it that extra mm or two or try a SRAM cassette (Rival would do the trick). also, i just had some shims made that would go between the front derailleur and the braze-on which should arrive in about 1 week. it’s a 6mm spacer which basically pushes the derailleur back (in an angle) allowing you to get a bit more clearance. we found out that this was the only way to make them work on the Specialized Transition. we also had a customer try one on a Guru (smaller size) and it works as well.
If its a slight touch, then judicious bending or filing of the front der may help. Also different brands of FD have different shapes and another on may not have the problem.
SRAM makes a front derailleur with two bolts for mounting to the braze-on tab. You sound like you are maxed out at the top, so the SRAM could be mounted higher (depending on the frame).
This could be an option thanks. Will see if I can get one of those shims from Rotor first…
Shimano Biopace and Rotor Q-Rings are not the same. They might seem like the same thing but they are not.
If you check the design carefully you will see that in Biopace chainrings, the maximum “chainring size” is at the dead-spot. In Q-Rings, the minimum size is at the dead-spot. Quite a difference and this IMO is why one works and the other does not. Q-Rings also permits you to fine tune the position.
I used a rat-tail file to increase the upper part of the slot on the braze on, and also bent the derailler tail up some. Now it works great.
I find the shifting about the same as before- lets be honest- no front derailleur really shifts that well, and how often do you shift it? 1x per hill- ie not very often.
I’m using the largest recommended ring delta, the 54/40 combo. In order to make it clear on a D/A front derailleur I took a dremel and did three modifications:
Enlarged the slot in my braze-on bracket. I think I took about 1mm of metal out of the slot, since it had plenty of thickness at the top. Depending on your mechanical aptitude this may be easy or hard. I used to run a machine shop in college so it was trivial to me.
Took a large-ish grinding stone attachment on the dremel and recontoured the back tail of the derailleur cage. The issue was basically the curvature of the QRing was a bit different than the curve of the cage. I probably took 1-2mm off of the cage.
I put a soft plated-steel washer between the derailleur and the braze-on bracket to space the derailleur towards the back of the bike. I simply looked through my jar of random washers until I found one that was about the right thickness (~1.5mm). I pre-bent it with needlenose pliers until it was about the same curvature as the braze-on bracket and then just put it in between and tightened things down.
Regarding shift quality, I have no issues slamming it into the big ring at any time. I had an older 52T from 4 or so years ago and it didn’t shift nearly as well as the newer rings. I suspect Gary’s made a few modifications to the ramps for better shifting.
True. I have set up two sets of Q-rings on two different bikes, and the shifting is good, but not as smooth as well adjusted round rings can be.
They will not make you faster.
Maybe. Maybe not. With my wife, she found a solution to a mild pedal stroke hiccup that she had - right at the dead-spot at 12:00. With Q-rings the hiccup disappeared and her pedal stroke is much smoother. Hard to know if she is absolutely faster - she did have a great year using them with some great results in the Pro ranks.
Shimano tried this gimmick 20 years ago.
As another poster pointed out, the design is very different.
Thanks again for shipping out the shim for my q-rings - great service from Rotor. Installed it a few weeks ago and so far no complaints from me - much better than before.
Ever so slight overlap below but you don’t notice it.
