Disc Brake Rubbing on a New-ish Cyclocross

IMS86

Hello All,

I'm new to this forum and I apologize in advance if I am posting this to the wrong section. I am desperate for advice on a problem I am having with my cyclocross bike. I have a Specialized Secteur with disc brakes that is just over a year old. I recently took it on a road trip, which involved taking it on and off a fork-mounted roof rack. Towards the end of the trip, the front wheel started making a periodic thudding sound with every turn of the wheel (sort of like a flat tire slapping against the concrete). It only occurs when there is load on the bike. I saw a bike mechanic and he claimed it was regular flexing of the bike, but the sound did not occur previously. I can ride with the sound, but it is really irritating and quite disparaging. Please help! I would be so grateful for any advice.

Other details - I am using pinhead locks. I notice sometimes they jiggle loose if I'm not careful to tighten them all the way. The brakes I have are SRAM/AVid 5.

Thanks,

Ingrid

roger_merriman

possibly a slightly out of true rotor?

bendertherobot

More likely it's because they are BB5's which are difficult to set up and keep in line (when you take something off).

You can waste a lot of time with them or install better brakes. TRP Spyre or Hy Rd.

silverpigeon

Disc brake rubbing problems I've had in the past 20 years or so have been solved by carrying out one/some of the following.

1. Remove the rotor and check if it is out of true. If yes, try bending it back using a truing fork (if you have one) If it's not out of true then refix to the wheel and nip up each bolt and tighten in clockwise order. Tighten the bolt in the 12 o'clock position first, then the 6 o'clock, 2 o'clock, then 8, 4 o'clock then 10. Keep going round until all the bolts are tightened to the correct torque.

2. Make sure your wheel clamp is not overtight. (Always found this to be the most common problem on other peoples bikes)

3. Loosen the caliper bolts and apply the brake. With the brake still applied re-tighten the bolts.

4. A small spacer on one or both of the caliper bolts.

Are you sure it's definitely the rotor? I had a similar sound once and the wheel was ever so slightly out of radial true.