New bike last year and the rear brake has always rubbed/made a noice like it’s catching the rotor.
So far I’ve tired:

I’ve bled the brake.
Tried New pads.
Different rotor.
Cleaned and oiled the pistons.
Tried the front brake on the back- does the same thing but no issues while bolted on the fork.
Tried a Hope brake on the back – same issue.

I think the brake must mount at an angle that’s making it catch. Could it be because of the type of mount?
Could the mounting surface or the mount need facing or could it’s just be a bent brake mount?

I’m at a loss to what’s up with it now. Anything I’ve missed before I go back to the bike shop?

You have tried a different caliper and a different rotor, yeah?

But the same mount? and the same wheel/hub?

try a different wheel/hub if you can borrow one easily?

or a different mount if you can.

Have you tried applying the brakes while the bolts are loose and then tightening them while the lever is still depressed? This will centre the caliper over the rotor.

Have you tried applying the brakes while the bolts are loose and then tightening them while the lever is still depressed? This will centre the caliper over the rotor.

Yeah about 20 times 🤷🏻‍♂️

You have tried a different caliper and a different rotor, yeah?

But the same mount? and the same wheel/hub?

try a different wheel/hub if you can borrow one easily?

or a different mount if you can.

Yeah tried all that. The mount is specific to the bike so it’s the on thing I can’t change.

Have you checked both pistons moving equally?

I have also had a brake where doing the pull the brake and centralise the brake hose was pulling it to one side causing a rub. Attempting to centralise the brake this way was actually just pushing the disc over. because of the tension from the hose

I always prefer to use the hope method anyway – cntrealise the caliper by eye then once its tight push pistons back to centralise them – vifdeo on the hope site

@ogden

” The mount is specific to the bike so it’s the on thing I can’t change”

i think you have your answer…

if youve tried all the other bits involved in the system!

can you try a smaller rotor/different mount?

I always prefer to use the hope method anyway – cntrealise the caliper by eye then once its tight push pistons back to centralise them – vifdeo on the hope site

Yeah that’s the way I’ve tried. I always find you need to coax Sram pistons out a bit on one side first.

if youve tried all the other bits involved in the system!

can you try a smaller rotor/different mount?

Yeah. I just wanted to check there wasn’t an obvious answer looking me in the face like.

@ogden

” The mount is specific to the bike so it’s the on thing I can’t change”

i think you have your answer…

if youve tried all the other bits involved in the system!

can you try a smaller rotor/different mount?

Edit – it will be a faff but…

transfer your caliper, wheel/hub and rotor to a different bike. i.e. everything but the mount. see if it still happens? It still could be the mount or worst case scenario, your frame.

Get the mount faced to ensure the calliper is square to the rotor.

If you’ve put the front brake on the back (I assume you mean literally bolted the whole caliper off the front onto that mount??) then it has to be the mount I reckon…. Try a smaller rotor so you don’t need the mount as ^^^ ??

EDIT – actually looking more closely at the pic it might be the case that you need some sort of mount whatever rotor size you have…

Do you have much freedom of lateral movement when the caliper is loose on the mount?
As you slowly tighten the bolts can you see the caliper moving sideways at all?

I once had a hub that had a dodgy rotor mount that slightly warped every rotor I installed, I ended up running four bolts instead of six until I replaced it with a pro4, it also rubbed when cornering sharply on flat ground, I run Hope E4’s and can clearly see when and where my rotor starts catching the pads, if your rotor is straight there could be some sideways drifting in the hub. If the mount is wonky you should be able to see the rotor catching the top of one pad and the bottom of the other.

I would check the rotor mount on the hub also. If you can get hold of a dti, remove the rotor and re insert the wheel and check run out of the face the rotor mounts too. A couple of thou at the hub is mm’s throw at the disc circumfrence