ales85

My biggest gripe with riding is the frequent brake rub when using disc brakes. I've got two bikes (cyclocross and road) and it happens with both. One with Tiagra (aluminum with carbon fork with Lapierre wheelset) and the other Ultegra Di2 (carbon with Mavic Cosmic SL 32 Disc Carbon UST). I ride down pretty fast and brake late, so I understand that some brake rub will always occur. But sometimes I have to actually straighten the rotor before the next ride or it will never stop rubbing. On one ride I've even straightened it during the ride, that's how annoying it was. It wouldn't straighten within 15 minutes of NO breaking (practically straight road).
I was told that the new rotor from 12-speed groupset should deal with this better (less expansion). Does anyone have any experience if this is true?

Or perhaps if the new calipers really do have that much more spacing, which would negate/reduce this issue?

Next issue is pedaling while standing. Not sure if it has to do with weight or power (I'm not a super strong rider, about 250+ FTP and 90kg). But when I stand up the disc rub appears again, notably with each stroke. I'm not sure if this is attributed to a flex in the fork or perhaps a flex in the wheel (spokes?).

I'm open to upgrading the wheel-set to something much stiffer, if it'd help with the issue.

cxwrench

How would stiffer wheels help reduce disc brake rub?

ales85

I've no idea, grasping at straws here

I was thinking that maybe the rotor is slightly misaligned (hub, through the wheel) when applying force this causes the rub.

The thinking is that standing pedaling also results in brake rub even after I sit down. It does mostly go away in a few minutes, but I'm interested in reducing the effect on the first place.

CliffordK

I think the OP is talking about disc brakes. So, I doubt it would matter much. Of course, really bad hub bearings could cause numerous woes.

I think what I'd do is start with a new brake rotor. I'm not sure of the best brand, but perhaps they're not all made the same. Try a major brand and not ultra light. Then make sure it is trued before the first use.

I have troubles believing the rotor goes bad every ride unless the rotor is made of really soft metal, or one is dragging the brakes down on a huge hill.

Got it so hot that it lost its temper?

Is this hydraulic or mechanical? Is it possible the tolerances are set too tight?

Atlas Shrugged

Something is wrong here. Myself and most of my riding buddies all use disc brakes without the problems you describe. Reading between the lines one area of concern is the constant truing of the rotors. When trueing the rotors there is potential for residual tension which once heated the rotor wants to return to initial state. The more truing is attempted the greater the release once heated again. I highly doubt new wheels would solve your problem.

biker128pedal

I wonder if the brake calliper pucks are sticking? I’m on my first hydraulic disc brake bike and only had it a few month but thought about this as there are a few threads on peoples brakes rubbing.

If the are like a car or motorcycle the seal design retracts the puck(s) a little when the brakes are released. Dirts can limit this.

Russ Roth

Buy better rotors. My mtb has had the same rotors for 4 years now and I've never needed to straighten them. Cross bike has been going a year and the same. Quick release hubs can have a problem with the rotors rubbing after each time you tighten or loosen the hub, changing hubs won't change that. If you have thru axle then a better hub can stopping rubbing if hub flex is an issue, from what I've heard, but I don't know how real that is. TRP makes some really nice rotors, with sandwiched materials that are a little heavy and typically about 35 each, but they are stiff and strong.

base2 

Over filled hydraulics never retract as far as they should.

Heat does cause issues. That darned thermal expansion's gotta go somewhere. I've had good luck with Icetech rotors, not so much with plain stamped stainless.

Out of adjustment bearings can cause issues. It never hurts to clean, regrease & readjust cup/cone bearings. Cartridge bearings are usually better left alone until they look/feel/sound crunchy.

Quick releases that aren't tight enough can cause issues.

Caliper bolts that aren't tight enough can allow the caliper to migrate under hard braking.

TRP Spyre/Spyke tend not to hold the pad adjustment. Age/use wears the interference fit/locking feature of the of the adjustment screws. If worn, the outboard pad will migrate with every brake application, IME.

Flexy forks can cause issues. Especially with side to side forces if you throw the bike around in a sprint or something.

Fork flex can cause issues.

If all else fails, & your system is mechanical, adjust the pads further away & learn to be happy with more lever travel.

scottfsmith

I had lots of rubbing problems with my rear disc brakes. Took them in a few times to the shop and still not fixed. They were not retracting far enough which then made the slightest wobble in the rotor or stand up riding cause a rub. I finally solved it recently with some spray lube on the sides of the pistons (with the pads removed).

ales85

Any suggestions? Currently I'm usingstock from Ultegra.
I never drag the brakes down the hill, can't ride fast if doing so
Hydraulic - Ultegra Di2.

That event with trueing on the ride happened only once. Other events were 2, maybe 3 times, in the past 6 months since I have the bike.
The funny thing is that a similar thing has happened to me on the previous bike with Tiagra (again hydraulic). So I really don't know if it's the aggressive braking with all the weight that the brakes must handle... But I'm not the only person with such characteristics in the world... I think?

Thanks to the rest for your comments as well, I'll try a couple of things when time permits.