brake rub on new disc wheels - SRAM force hydro

mpatts

In an attempt to be all clever in my "Yeah I can use one bike for lots of things" I got a new set of wheels for my Boone, so I can run slicks without faffing around with tyre changes.

Rear fine and dandy. Front 'grips' and won't spin freely.

Things its definitely not:

no rub on old wheels

I think I've ridden for about 50 miles on the pads

The wheels are aligned with no play (they are essentially new)

I don't think the rotor is bent, its consistant grab

The pistons arent sticking

I have googled a lot and watched a few youtube videos, to no avail.

bendertherobot

When you say the wheels are aligned, do you mean the discs? Even changing rotors can have an effect.

Essentially you need to, undo the bolt on the mount to allow some free play, grab the lever hard, tighten.

Should work then. But I assume that's what you've done and, if so, hmm..

i.bhamra

Do you have the correct axle end caps fitted to the wheel?

mpatts

i.bhamra said:

Do you have the correct axle end caps fitted to the wheel?

Of course, this is exactly the type of detail I run to when I'm buying new stuff

(I've no idea, I'll go out now and check.....)

me-109

Sounds like the caliper just needs aligning on the rotor. Very slight difference in offset between the two sets of wheels so one side of the rotor is rubbing.

N0bodyOfTheGoat

I usually have to tweak caliper alignment when I switch between my Fulcrum and Hunt wheels on the Cube, which have their own set of rotors.

joe_totale-2

N0bodyOfTheGoat said:

I usually have to tweak caliper alignment when I switch between my Fulcrum and Hunt wheels on the Cube, which have their own set of rotors.

Same here with my CX bike. I find it also helps to use a flat head screwdriver or tyre leaver to push back the pads as well.

Charlie_Croker

Essentially what bendertherobot, me-109, N0bodyOfTheGoat and joe_totale-2 ^^^ are all saying, the caliper and pads need setting up from scratch (ie pads all the way back in) with a different wheel. Sounds like you’ve got lucky* with the rear wheel/disc alignment. But not so the front. Might be worth checking the rotor thicknesses if that doesn’t solve the problem.

*I have no doubt there will be ‘a standard’ for the position of rotors relative to the hub, but QC/engineering have been lacking in other bicycle manufacturing areas also

veronese68

I agree that there is almost certainly a small variance in disc alignment. If you look carefully you should be able to see which wheel has the disc further in towards the hub. You can buy shims to move the disc out slightly so the two sets of wheels match more closely. This should make it easier for future wheel swaps. Assuming the brakes are hydraulic even if they are not perfectly aligned the hydraulics will allow for a tiny bit of variance.

pilot_pete

joe_totale-2 said:

N0bodyOfTheGoat said:

I usually have to tweak caliper alignment when I switch between my Fulcrum and Hunt wheels on the Cube, which have their own set of rotors.

Same here with my CX bike. I find it also helps to use a flat head screwdriver or tyre leaver to push back the pads as well.

Be careful using a screwdriver to lever the pistons back in if you don’t have a set of pads in the caliper - you can crack the ceramic piston. If you do have pads in and use a twisting motion of a large screwdriver you will not damage the pistons, but can put a gouge in the pad(s). If I am replacing the pads I use the old ones to lever against with a large screwdriver to push the pistons back before binning them. If not I use something plastic like a tyre lever as I don’t have the proper tool.

PP

joe_totale-2

pilot_pete said:

joe_totale-2 said:

N0bodyOfTheGoat said:

I usually have to tweak caliper alignment when I switch between my Fulcrum and Hunt wheels on the Cube, which have their own set of rotors.

Same here with my CX bike. I find it also helps to use a flat head screwdriver or tyre leaver to push back the pads as well.

Be careful using a screwdriver to lever the pistons back in if you don’t have a set of pads in the caliper - you can crack the ceramic piston. If you do have pads in and use a twisting motion of a large screwdriver you will not damage the pistons, but can put a gouge in the pad(s). If I am replacing the pads I use the old ones to lever against with a large screwdriver to push the pistons back before binning them. If not I use something plastic like a tyre lever as I don’t have the proper tool.

PP

Good advice. I should have mentioned that I'd only ever use the screwdriver with the pads in and be quite gentle as there's no need to push back with force.

mpatts

well....fixed

it was indeed the "loosen off caliper, retighten" trick. Thanks for your help, and I am an idiot.

fenix

Good to know you got it sorted.