Disc brake squeals when damp

david37

I cant stand squeeling brakes. in that respect Disc brakes on a road bike are definitely a step back

zest28

david37 said:

I cant stand squeeling brakes. in that respect Disc brakes on a road bike are definitely a step back

It is step forward. My $3500 carbon aero wheels are still brand new and will last a lifetime thanks to disc brakes.

I would never ride a pair of $3500 carbon wheels with rim brakes, especially in the mountains with descents that have clear speed limits, meaning you have to be on the brakes constantly.

rafletcher

Some days the rear disc squeals (like today), some days it doesn’t (like yesterday). No cleaning done. It’s the moisture in the air and the fact the rear disc and pads are cold.

paulbnix

With the current weather still providing plenty of testing opportunity I decided to try copper slip.

I put some on the face of the pistons in the rear brake calliper and went out today on a fairly flat ride in Cheshire.

I think it is an improvement.

Both rotors were getting wet during the ride and squealed.

However the squeal from the rear was short and then stopped until the next time it got wet and I subsequently braked.

The front squealed for much longer.

It made an interesting ride as I normally favour the front brake and just use the back to add to the stopping power. Today I was trying to just use the back.

I think I will try some copper slip on the front brake.

darrell1967

It’s a good way to let pedestrians know you’re behind them.

david37

zest28 said:

david37 said:

I cant stand squeeling brakes. in that respect Disc brakes on a road bike are definitely a step back

It is step forward. My $3500 carbon aero wheels are still brand new and will last a lifetime thanks to disc brakes.

I would never ride a pair of $3500 carbon wheels with rim brakes, especially in the mountains with descents that have clear speed limits, meaning you have to be on the brakes constantly.

ive got a set of zipp 303s on my rim brake bike, ive had them for seven years, they havent worn out and i use them a lot. i stopped getting precious about them. i use them in the wet the dry on flat and on mountainous or flat routes. in dry dusty conditions and in winter. I just dont bother changing them.

The braking was dreadful but the pads i have now solved all that. they havent worn out, but they have become obsolete with the changing of tech. Ive changed the bearings umpteen times and the pads even more.

i suspect if looked after that most decent wheels are capable of lasting just as long as the bike itself. and they dont squeel.

they do make a noise like a cylon from buck rogers though

paulbnix

I think I now have a workable solution.

I have replaced the front SRAM Centreline rotor with a Shimano RT70 Ice Tech rotor - same type as the rear.

I still get a squeal when the rotor is wet but it goes quiet quickly.

It's now behaving similar to the previous bike that had Wiggle Lifeline rotors.

I wonder if it is the hole shape and distribution.
As you can see in the picture the RT70 (left) and Lifeline (centre) are similar and the SRAM (right) is quite different.

chaymck

Anyone tried disc brake conditioner?

I have a spray can but not yet used it.

Motip branded.

ballysmate

chaymck said:

Anyone tried disc brake conditioner?

I have a spray can but not yet used it.

Motip branded.

Never heard of it tbh, let us know how you get on.

Just googled it. S ounds like an unnecessary product tbh though. It says it prevents wear and as all brakes are reliant on friction, I am somewhat dubious as to its benefits.

grobe02

I'm surprised at all the fans of disc brakes--even if they do save rims. A few years ago on a sunny April day I set out on my then brand new 2017 Specialized Venge (that heavy and now obsolete super aero bike with disc brakes as standard equipment). Later on, dark clouds rolled in, and as I headed back to town a hailstorm sent icy pellets bouncing off the road. Oil on the pavement soon thoroughly contaminated the brake pads--first came the screeching squeal, then almost no braking power. Not a good feeling. I am not against hi-tech (my everyday bike has airless TANNUS tires), and my next superlight bike will probably have e-tap. But disc brakes? Never again, not unless Shimano et al. do some serious re-engineering. As for the Venge, I am now almost afraid to ride it!

davyjones2000anj00DDs

Main reason I'm going back to rim brakes. Absolute ball ache and impossible to stop. Mine are so loud it's actually embarrassing

ballysmate

grobe02 said:

I'm surprised at all the fans of disc brakes--even if they do save rims. A few years ago on a sunny April day I set out on my then brand new 2017 Specialized Venge (that heavy and now obsolete super aero bike with disc brakes as standard equipment). Later on, dark clouds rolled in, and as I headed back to town a hailstorm sent icy pellets bouncing off the road. Oil on the pavement soon thoroughly contaminated the brake pads--first came the screeching squeal, then almost no braking power. Not a good feeling. I am not against hi-tech (my everyday bike has airless TANNUS tires), and my next superlight bike will probably have e-tap. But disc brakes? Never again, not unless Shimano et al. do some serious re-engineering. As for the Venge, I am now almost afraid to ride it!

@grobe02
If you are still here, how much of the said oil from the pavement made it onto the rims and how would it have impacted rim brake efficiency?

ballysmate

davyjones2000anj00DDs said:

Main reason I'm going back to rim brakes. Absolute ball ache and impossible to stop. Mine are so loud it's actually embarrassing

Embarrassing, perhaps. But do they work in the wet?

davyjones2000anj00DDs

ballysmate said:

davyjones2000anj00DDs said:

Main reason I'm going back to rim brakes. Absolute ball ache and impossible to stop. Mine are so loud it's actually embarrassing

Embarrassing, perhaps. But do they work in the wet?

Not any better than my direct mount rim brake bike. The lever feel on the rim brake bike is MUCH more positive and generally nicer too.

paulbnix

My workable solution- the Shimano RT70 rotor - has been a lot better in reducing the squeal until I was caught out today in what felt like a flash flood 😟
Those brakes did squeal and squeal but they continued to stop me when I needed them to. I think my rim brakes would have struggled.

grobe02

I cannot say if contamination would have been as bad on my rim-braked bike during that hailstorm—it has soft brake pads designed for wet weather, and I have yet to have problems in the rain. I do know the weather that day was exceptionally nasty—like being inside a washing machine filled with ice pellets. The asphalt in my corner of North America often has an oily film when rains follow prolonged dry spells. And I have read you should not use sprays like WD-40 EVEN NEAR a disc-braked bike to avoid contamination from drifting oil. Mountain bikers may be more enthusiastic(?) about discs because of the surfaces upon which they ride—porous materials like gravel, dirt, and grass with no oil pooling. The comment from paulbnix is encouraging—I would replace the Venge’s rotors if that would fix the problem. But I have invested the equivalent of £6,000 in this beautiful but heavy bike, and would rather focus funds on my next ultra-light machine.