Disc brake troubles

jonny_trousers

Hi all,

Okay, so to get straight to the point: I fairly recently bought an Edinburgh bicycles commuter through Ebay that was in as new condition. It's a great little bike and suits my needs just perfectly but for one problem: the disc brakes (cable operated). I would never have opted for them if I was buying new, but I obviously had no choice. Anyway, they brake beautifully, but the rear pads permanently rub against the rotor. I tinkered around without much luck before taking the bike into Brixton Cycles. They told me that the issue was simply that they were new pads and therefore needed wearing in and so I carried on with my riding. I cannot help but feel, however, that this seems a bit strange as surely they should be adjustable? Sure, I am probably getting a more intense workout by riding against the extra resistance, but it has to be making things that little bit harder work - something I can well do without at 11:15 at night when I am tackling the last rising mile home - not to mention the annoying sound. Part of me feels like just binning the disc brakes and getting some decent V brakes instead, but is that me giving up too easily?

So, my questions are: Are Brixton correct and that it is just a matter of time before the pads are sufficiently worn in? Should I be able to sort them out myself? Or, should I just kit my bike out with simpler brakes instead?

Thanks for any thoughts.

nicklouse

and the brakes are?

which pad is rubbing the inner or the outer.

or....

jonny_trousers

nicklouse wrote:

and the brakes are?

which pad is rubbing the inner or the outer.

or....

Thanks for your reply Nick,

I would say the worst offender is the outer pad (the one on the mechanism side) although the inner seems to be rubbing a little also. I've swapped the pads over without success and have now resorted to slackening the tension in the cable, which makes the rear brake pretty unresponsive, yet still there is rubbing.

Having never ridden a bike with disc brakes before the pads are new to me, but looking at how tough they appear, I suspect it would take me a year of hardcore riding to wear them down sufficiently.

The brakes are Tektro, which I would guess are way down at the budget end of the disc brake spectrum. I have looked at the geometry of the mechanism in as much detail as possible and cannot see anywhere that I can make adjustments to create much of a difference.

I'm thinking my plan to chuck in the towel may be the least painful option.

Cheers!

nicklouse

Ok back to the start.
the inner "piston" will be adjustable by an allen key fitting where you can wind it in or out.

this should be sett as close to the disc as possible. as the disc is pushed onto it and as little deflection as possible gives the best result.

the other adjustment is the actual caliper position. and the two caliper mounting bolts.

Now consider that the caliper wants to set where the rotor is well clamped.

adjust the inner piston to a close position and then while applying the brake undo the bolts and allow the caliper to move to the position. re tighten bolts. and then tweek inner pad position. ride and bed in again.

Mech brakes can give very good power when set up right.

more info here
http://www.tektro.com/04support/manual.php

jonny_trousers

Thanks again!

God they are fiddly buggers aren't they? I've had a mess around and have improved things, but they are still rubbing a little. I seem to have the choice of useless brakes and no rub or brakes that work and skim the rotors permanently.

I do think that Brixton Cycles may have told me a porky though, which is a little sad as I always thought them to be an excellent company.

Not sure where to go from here. We shall see.

nicklouse

get them so that they work well and then let them bed/wear in.

job done.

jonny_trousers

Annoying as hell: got home from pushing it quite hard only to discover that the brakes had locked themselves even tighter shut than before. I'll ring Edinburgh Bicycles in the morning. Grrr!

jonny_trousers

So I rang EBC and, polite and friendly though they were, they were of absolutely no help. I then called Brixton Cycles who suggested I bring the bike back in. I did, and purely by coincidence, I got to speak to the guy who had looked at my brakes in the first place. He told me that he wasn't surprised to see the bike back as he hadn't really managed to sort it out first time around. He suggested that the caliper was probably buggered and that the best course of action was to fit a new one.

I'm pleased to hear that it was not just a case of me being a spazz and that there was something seriously wrong all along, but I do wish Brixton Cycles had just told me in the first place. They are not going to charge me labour and I can stomach the price of a new brake, but it was all a bit of a waste of time and effort. Fingers crossed this sorts it.

Thanks for taking the time and effort to offer your advice Nicklouse