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I've been riding discs on my road bike for 5 years now and every time I go out in the winter on wet days I spend half my time plagued by the sound of grit scrapping away on the rotor. I'm assuming the grit must get picked up and just collects around the pad or in between the vent holes on the rotor?
I run long mudguards front and rear, so I am minimising the crap that's picked up. I suspect this is just one of those things you just have to accept with discs in the winter?
Noticed this problem at the weekend - seems to be worse after riding through puddles?
seems to be worse after riding through puddles?
Yes. I go through puddles to see if the water spray will get rid of the grating sound, but half the time it just changes it from one annoying grating sound to another one. Even if I brake and then come off the brakes the noise is still there. Eventually, it disappears only for it to happen again at random intervals.
SRAM? Same issue with rival hydros. Mud or water either seems to be the cause. I’ve pondered if road disc to rotor clearance less than on mtb hydros? As never have same issue on my mtb.
Haven't found a way to avoid it, but in my experience sintered pads are actually quieter than organics that get contaminated much quicker.
SRAM?
No. Shimano br-rs785 calipers.
Try and see where the water runs after hitting the mudguards, I had an issue with a mudhugger gravel front where the crud was running down the fork leg into the brake. Solved with a zip tie to redirect it.
Try and see where the water runs after hitting the mudguards, I had an issue with a mudhugger gravel front where the crud was running down the fork leg into the brake. Solved with a zip tie to redirect it.
Very clever! I suspect even with mudguards you will still get a fair amount of water run down the fork leg and rear triangle into the caliper. Maybe that is the culprit rather than water coming off the road directly onto the caliper / rotor.
I'll give that a try. Thanks
Maybe we should start fitting MX style gaurds in Winter 😉
I have recently put Hope RX4 callipers on my gravel bike. They have a bit more clearance between pads & disc. They were loads easier to set up than the Shimano GRX callipers they replaced and seem to reduce the grinding noise too. They do still occasionally make noise but it’s definitely less noticeable.
I suspect it may be gritty water dripping off the mudguard, either directly onto the disc or down the fork leg as suggested above.
I've got Rivals on my gravel bike and regularly get the bike completely covered on mud, the brakes normally only scrape when I've attempted to ride through mud and water that reaches the disc.
Mudguards are great for keeping the rider clean but just dump the crud onto your discs and drivetrain
I’ve had SRAM force previously and now have Rival. I’m convinced the pad clearance is much less than any MTB I’ve owned. It’s just so difficult to set them up without any rubbing. I changed pads on mine last night and it’s rubbing like mad despite the pistons being pushed right back.
On MTB you can get away with slightly out of true discs but no chance on the sram HRD setups
Just go fixed gear brakeless and have silent riding all year around, it's great.
Its rim brakes you need.
Rather hear your discs grinding than your rim.
If only they'd mount the caliper on the seat stay rather than the chain stay.
I have mudguards, and I only get gritty discs just after puddles as you'd expect. So checking the water flow on your particular setup is probably a good idea.
If only they’d mount the caliper on the seat stay rather than the chain stay.
I was just wondering how rear caliper placement affects this. I've been riding a disk-braked road bike for 12 years and haven't had a big problem with this. I was using BB7s for most of that time and they work best with almost zero pad/rotor clearance. Now using Shimano hydraulics.
Mudguards are great for keeping the rider clean but just dump the crud onto your discs and drivetrain
A problem of basic mudguards or poor fit? Longer fronts generally ie upper extension and lower flaps help, also rolled edge metal guards.
I had this all the time with my SRAM Force Hydro brakes. No matter what I did I couldn't stop it (changed pads, cleaned pistons, lubed everything, re-bled brakes... all multiple times).
Then I found this vid from PsiMet: PsiMet SRAM Master Cylinder Strip/Service
It guides you how to strip, clean, service and lubricate the master cylinder and its seals. And it cured my disc brake rub problems.
No idea if this is the same issue on Shimano brakes, but all road callipers do seem to run closer to the pads than their MTB brethren for some reason, no matter what brand.
It's an annoying PITA that manufacturer's really should have engineered out by now - after all, it's not like disc brakes are some kind of new-fangled, early-stage innovation(!). Grrrr!