boshk

My Diverge comes with TRP Spyre mechanical disc brakes.

I think my front disc rotor is slightly bent, its still works (just about) but I have to move the pads out to avoid constant rubbing but that in turn increases the brake lever travel.

I want to replace the rotor, do I need to use TRP ones or can I buy other brands 160mm?
anyone have any experience replacing a TRP spyre rotor?

quicktrigger

How about fix the rotor. There are wrenches for doing this, or have your LBS do it.

dabac

There are supposed to be less succesful combos out there. But I haven't had any trouble as long as I've matched diameter and mounting system.

Tim_Iowa

You can use any 160 mm rotor you want. You just have to match the mounting system, 6-bolt or Centerlock.

But @quicktrigger is completely correct; you should try to true the rotor first. A bent disc is common with disc brakes, and easy to fix.

You can get a specific rotor truing tool, but a simple adjustable (crescent) wrench works fine if you're careful.
A work stand is very helpful, or you can just flip the bike upside down (preferably indoors on a forgiving surface).

Seattle Forrest

I bought a set of Shimano Ice Tech Freeza rotors. Like them very much. They're an improvement over the SRAM rotors my bike came with, and I'm using SRAM brakes.

My new rotors came slightly bent ("out of true"). This is a thing with disc brakes. There's a tool to fix them and it's a pretty quick and easy job.

cellery

Yep. The adjustable crescent wrench likely already in your toolbox is what you seek. Clean the gripping surface off with rubbing alcohol first to prevent oil/grease/dirt from contaminating and be careful not to scratch the rotor. Shine a flashlight at the caliper parallel to the rotor while spinning the wheel and look into where the pads sit and you will quickly see where it is rubbing and which way you need to bend it.

boshk

thanks.
I tried the adjustable spanner, still the same, but my spanner is small, maybe use more force?

I tried the cable tightening...same
thought it might be the brake callipers installed at an angle but I don't have a disc clam thing so all I did was loosen it, grab the brake, retighten.
Can pads be installed 'wrong'?

maybe I should take the disc off and see if it lays flat on an even surface....if it does, then I have other issues?

I had a look at the truing tool, its about the same price as a new rotor haha

Tim_Iowa

I understand your frustration, but you really need to learn to true the rotor if you're going to own a disc brake bike. You may end up truing a rotor dozens of times before it's worn out.

And I repeat my assertion that a small adjustable wrench will function just as good as the truing tool, if you're cost-conscious.


Rotors are made of steel, which is springy. This means you have to bend the rotor farther in the opposite direction than you want it to actually bend. It will spring back somewhat.
When I true a rotor (which I have to do on about 50% of the bikes I assemble at the shop), I grab a spoke and pull the wrench almost all the way to the spokes (when truing inboard). It seems like a lot, but a small force won't bend the rotor enough.


As for setting up the pads/caliper wrong, that's entirely possible as well. I've found that loosening the bolts and squeezing the brake only gets the caliper in a rough position.
Although, if you use spacers between the rotor and pads in this step, then it seems to get the caliper more reliably aligned. For spacers, I use a couple thin leaves from a feeler gauge. Others use business cards or playing cards.

Even so it may not be perfect. I will tighten the bolts partially and then nudge either end of the caliper in or out until it spins without rubbing. Keep your finger tips out of the rotor when nudging the caliper! My fingertip can tell you why (several stiches).

Once your rotor is true and your caliper is aligned, then you can increase the cable tension in order to get a short, strong lever pull without rubbing.


The bikes I assemble at the shop always have excellent, strong brakes with short lever pull, and it's because I take an extra 10 minutes making everything just right.

It sounds like a pain, but you'll never know how awesome disc brakes can be unless you get them set up right.

boshk

Thanks mate, I purchased a bike stand and a truing tool right after I made the post. Figured a stand would help in general maintenance anyway and I should try a true the rotor and wheels if I want to get the best out of it.