Do brake mounts differ by manufacturer?

Greer_

I'm only realising this since replacing the pads on my Shimano M596's (they replaced tektro comps), but the old brake pads have ridges on them where the rotor wasn't using all the brake pad - about 6-7mm is untouched. If I change to a shimano mount will it make the rotor use all the pads? i.e. are they measured differently? I was of the opinion they were all the same size between manufactures.

The current mount is a tektro IS-PM 160mm. Nothing else has changed bar the calliper.

Also, the new pads (SS Kevlar) seem a bit too thick. With the pistons fully retracted, and everything fitted, the wheel won't freewheel due to the pads being a tight fit to the rotor. I'm guessing it wont hurt to file them down a tiny bit?

Cheers.

nicklouse

if they are different then how would they all work on the same standard?

they all have to work on the same 6" post mount with a 6" disc. so it should not matter what adaptor you use as they are all designed to work to the same standard.

Greer_

That's what I thought, but went into the LBS yesterday and I was told getting a Shimano mount should fix it as they're measured differently - no idea why/how which is why I didn't buy it.

Any ideas on why there's this gap then?

nicklouse

it may not be the adaptor.

sounds like you have a tad too much fluid in the system as well.

Greer_

Problem with the calliper then? I was going to say nothing else has changed ... but the wheels have - Superstar Switch hubs, but as the bike revolves around the hub I doubt it's that.

Could be too much fluid, but the pistons will fully retract. I may let out a tiny bit though.

nicklouse

you have re set the caliper when you changed wheels?

Greer_

No, I didn't touch the brakes when I changed wheels, bar to stop them from rubbing if that's what you mean by reset? I'm not sure how that would fix the top of the pads not being used.

nicklouse

the calipers will need positioning as no hubs are the same.

Greer_

Thanks for your help nick. What do you mean by positioning? (I sound like a noob here! - well I still am but fix most things myself after a little help). Unscrew all the mounts and put them back on? I didn't think there was much adjustment you could do, bar side-to-side.

cobba

Greer_ wrote:

I'm only realising this since replacing the pads on my Shimano M596's (they replaced tektro comps), but the old brake pads have ridges on them where the rotor wasn't using all the brake pad - about 6-7mm is untouched.

Overhanging pads is bad, it can lead to brake failure.
6 to 7mm of unused pad means that something is wrong.
5mm of the pad braking material overhanging the outer edge of the rotor means that the caliper is packed out enough to use a 170mm rotor.
10mm of the pad braking material overhanging the outer edge of the rotor means that the caliper is packed out enough to use a 180mm rotor.

Take a side on photo of the brake setup that shows the brake, the adapter, the rotor and post it on here.

If we can see your setup we might be able to identify what's wrong

mrmonkfinger

Greer_ wrote:

I didn't think there was much adjustment you could do, bar side-to-side.

That's pretty much it - just re-align the calliper sideways.


Incidentally, is the adaptor installed the right way around? That might explain the unused 6mm.

The Rookie

What I was thinking.......

Greer_

I hope the quality is good enough, had to use my phone. Thanks for the help so far.

cobba

That's strange, you have the adapter on the right way around and the adapter you have should work.

The adapter you have is the A-3 from Tektro's AQ Series Adapters which is basically the same as a Shimano 160mm Rear Adapter or a Superstar Type 2 adapter.
I don't think that a new adapter would change the alignment problem.

Do the pads from the old brake have a similar wear pattern ?

Greer_

Yeah I didn't think a new adaptor would fix it, and nope the old brakes didn't have this problem.

nicklouse

time to get the file out.

or try a 140mm rear adaptor and some washers.

cobba

nicklouse wrote:

try a 140mm rear adaptor and some washers.

That'd be the best option of the two.

Greer_

Looks like I'll head back round to the LBS then and try a few different mounts out. Won't get it done before the race this sunday but it should work fine for it. It's only when it wears right down that problems are caused.

cobba

If you've got a 160mm front adapter you could use that, a 160mm front PM to IS adapter is the same as a 140mm rear PM to IS adapter.

How far away from each other are the unworn parts of the brake pads when you squeeze the brake levers.

Greer_

Nope I have no spare mounts. When I noticed the brake pads were dead, it was while I was out and the rear wheel had locked up for some reason - guessing the pads were touching and stopping the wheel moving. That was after 4-5 months abuse though and they are only organic pads. I had to separate the pads, and I just went straight home only using the front brake.