Cycling UK Forum

robing wrote: ↑30 Oct 2024, 5:04pm I need some help with this please. I am relatively new to disc brakes. Only my newest bike has them - cable ones. I'm struggling with adjusting them, the front in particular. They have 4 mounting bolts (2x2 at right angles), cable tension adjusted by barrel adjuster/clamp and a side bolt - you access through the spokes which I believe adjusts the pad in/out from the disc.

I'm struggling to stop it from rubbing.
My LBS said to loosen off the mounting bolts, apply the brake and then retighten.
If I loosen the side bolt/pad adjuster too much the brake doesn't work.

Out on my ride today it was rubbing and I could feel the extra resistance. I managed to solve it by reducing the cable tension, then was able to tighten the pad without it rubbing. All seems well for the time being.
Any tips or links to videos gratefully received.

Only one pad moves, the other is fixed.

Eyebrox wrote: ↑30 Oct 2024, 6:28pm Loosen the caliper bolts and manoeuvre the caliper towards the fixed pad. Use feeler gauge or a business card to judge the closeness of the position between the disc and the fixed pad/piston. Tighten up the caliper bolts. Position the moving pad using the bolt through the spokes. Use the feelers or a business card to set the same amount of space between the moving pad and the disc as you will have done for the fixed pad size. Only use the adjuster as the pads wear, turning it anti clockwise to nudge the moving pad in. Think that should do the job.

531colin wrote: ↑30 Oct 2024, 5:39pm What brake?....manufacturer, model?
Photo as well won't hurt.

Most cable disc brakes work by 2 discs, one fixed, one turns....as it turns, 3 tiny ball bearings move in grooves to clamp the pads together.
If you are not careful, its possible to wrongly adjust the brake so that it runs out of travel....once the ball bearings are at the top of their groove, there is no more movement.
Don't do this!

robing wrote: ↑30 Oct 2024, 6:31pm ...
How do you add a photo?

Audax67 wrote: ↑31 Oct 2024, 8:36am Qu. to the panel: if they're called disc brakes and the thing the caliper clamps onto is patently a disc, albeit a bit holey, why TF do they call it a rotor?

rareposter wrote: ↑31 Oct 2024, 9:50am
In answer to the OP, I've found that the best method of adjusting cable disc brakes is to remove the entire brake mechanism from the bike, place it into a bin and then fit some hydraulic discs.

Cyclothesist wrote: ↑31 Oct 2024, 10:23am Rather harsh, but there are some awful mechanical disc brakes out there as well as some gems.

robing wrote: ↑30 Oct 2024, 5:04pm Any tips or links to videos gratefully received.

rareposter wrote: ↑31 Oct 2024, 9:50am

Audax67 wrote: ↑31 Oct 2024, 8:36am Qu. to the panel: if they're called disc brakes and the thing the caliper clamps onto is patently a disc, albeit a bit holey, why TF do they call it a rotor?

Because it rotates.
Rotating disc = rotor

Technically, "disc brake" refers to the entire system including the caliper and lever whereas rotor means the actual metal bit bolted to the wheel but in practice the terms are used pretty much interchangeably. In America it's a rotor; in the UK it's disc or rotor or disc rotor or (depending on the mechanical nous of the customer bringing the bike into the shop) "that thing that stops me".

In answer to the OP, I've found that the best method of adjusting cable disc brakes is to remove the entire brake mechanism from the bike, place it into a bin and then fit some hydraulic discs.