Hi I have an annoying rear wheel rotor rubbing against disc brake pads. I have looked at some online videos on how to solve the problem. They all suggest loosening the bolts attaching the calipers to the frame then whilst squeezing the brake lever retighten the bolts. Thats all well and good for the front brakes but how do people manage to squeeze the rear brake lever whilst tightening caliper bolts located beneath the chain stay. Does anyone have any tips? BTW my bike is equipped with the latest Ultegra group set
You just need something to squeeze the brake levers - a friend, a strap, bungee, electrical tape, etcâŚ.
This method of pulling the lever and tightening the caliper seldom works. It never works on frames with missaligned flatmounts or with a caliper with one lazy piston.
Usually you just need to set the caliper by eye.
If your frame has misaligned flat mounts, the caliper will sit skewed compared to the disc, the pads wonât be parallel making it sometimes impossible to set rub free.
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Thereâs a lot of missing info. Has been a problem from when you got the bike? If so, itâs possible the brake mounts are not faces correctly or never were. Recent issue? Have you have the brakes maintained, with a clean up/inspection, new pads, etc? If not, you may well be due, since you may have a stuck caliper. Have you looked at/trued the rotors?
As for Squeezing the lever as one is tightening the caliper to center, if done right you donât have to man-handle the lever to center the caliper.
This. Iâve had better luck when I just squeeze enough to close the pistons and no more. That being said, I agree with the others that the planets need to be aligned for this to work. It works maybe 20% of the time and mostly with new builds. Once your pistons get a little gummed up, this method doesnât work anymore because one of the pistons almost always moves more freely than the other. Dave Rome would say this is an excellent opportunity to clean and service your calipers and he has a great Threaded article covering how this is done. Thanks to Dave I have the requisite bottle brush hanging on my tool wall, along with the Chris Heerschap 3D printed brake blocks that make this an easy task.
If your caliper mounting bosses are not square and need to be faced, you can either take it to a bike shop to face them, or do what most people do and just adjust the caliper using patience, a good hex wrench (or T25), and a white piece of paper on the floor so you can see what direction the caliper needs to move. Note that the act of tightening the caliper will move the caliper (annoyingly so) so you will have to account for that.
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My bike was serviced not long ago , which included a brake bleed etc. This makes it frustrating especially since it first occurred whilst out riding. Previously I have had problems with the brakes squealing and vibrating. The wonders of disc brakes are way oversold. They are so temperamental and require lots of attention. Rim brakes in comparison are so easy to look afterâšď¸
Personally, Iâd take the bike bacl top the tech who did the service. Either a step was missed or bungled. As for discs vs rim brakes, which is easier can be argued either way. The upside of consistent power and modulation, plus easy of pad replacement makes discs a win in my book. But when things do go sideways discs can be a PITA.
Sounds like the rotor was not true. Itâs possible they re torqued the bolts and that caused the issue. Vibration/pulsating wonât go away if the rotor is not true.
Squealing is going to happen. Thin rotors are prone to oscillation. In some cases a bit of grease between the rotor and the hub can help. âIn some casesâ.
I would go back to the shop. Not that it was their fault but they might be able to figure it out.
Good luck
In some cases a bit of grease between the rotor and hub can help.
Iâm not sure thatâs a great idea. The heat from the rotor will thin the grease, and the rotation of the wheel could then cause it to migrate out onto the brake surface, potentially becoming not just the cause of a squeal but also of poor braking.
I agree, if itâs over applied. Iâm talking thin , wiping off any you see with you eyes. It does not take much to act as an insulation layer.