Disc brakes rubbing

[Kajjal]

Bit of a strange one, on my diverge which has br-r785 disc brakes which are pretty much the same as my mountain bikes m785 brakes, i have put in new pads and they won't stop rubbing. I did the below but the pad to disc clearance is very small.

Removed old pads
Cleaned rotor and caliper checking for debris
Pressed pistons gently back into calliper
Put new pads in and fitted wheel (bolt thru)
Set gap by eye and rode bike breaking hard several times
Rubbing still, did caliper again by eye but gap is very small and can't stop rubbing.

On my mountain bike the disc clearence is bigger to the pads and so the adjustment easy to make and good performance with no rubbing.

The brake works very well with the new pad in, it is just annoying having rub on a road bike. The pads are the same as on the bike previously.

Any ideas ????

 

[13 rider]

I had an issue with my front disc rubbing I solved it by removing the quick release and then refitted it but not as tight and it cured the rubbing . Believe by having the skewer really tight it was pulling the forks in just enough to make the brakes rub . Worth a quick fettle

 

[lpretro1]

Just go and ride and let the pads bed in - should go away after a couple of rides tops

 

[Plumster]

Have you centralised the caliper (loosen caliper bolts, pull brake while tightening caliper bolts)?

 

[fossyant]

Disc isn't slightly warped ?

 

[I like Skol]

Disc isn't slightly warped ?

Probably this ^^^^
In my experience most rotors are not perfectly straight. Some are just more straight than others.....

 

[fossyant]

Adjustable spanner will sort slight warping.

 

[Kajjal]

Thanks for the suggestions, much appreciated,

It is a bolt thru and done up tight, reseating has not made any difference.
Tried adjusting by eye and the undo, brake on retighten method.
The disc may be slightly warped but the gap between pads and rotor is consistently very small compared to my mountain bikes xt brakes.
I will have a look at the disc more closely and ride the bike hard and down steep hills to see if that helps.

Any other suggestions would be appreciated, thanks.

 

[fossyant]

Is it creating noise ? My hydraulic Guide RS's sit further from the disc than the kid's cheaper cable brakes.

There is supposed to be an adjuster 'allen bolt' on the lever housing to adjust free travel on the road hydraulic brake you have ?

My Guide RS's have no 'pad distance' adjustment - not needed actually. I can tweak the kids bikes cable brakes !

 

[Kajjal]

Is it creating noise ? My hydraulic Guide RS's sit further from the disc than the kid's cheaper cable brakes.

There is supposed to be an adjuster 'allen bolt' on the lever housing to adjust free travel on the road hydraulic brake you have ?

My Guide RS's have no 'pad distance' adjustment - not needed actually. I can tweak the kids bikes cable brakes !

My xt brakes work fine and easy to setup and adjust. If these brakes had a little more pad to disc clearance they would be fine.

I will double check but i think that adjustment is for reach and when the brakes start to bite rather than the pad gap.

Thanks

 

[I like Skol]

I also have a set of the R785s as well as two bikes with the XT M785s. The R785s appear to be exactly the same to set up and align with no more rubbing issues than the MTB version. Are the new pads genuine Shimano items? Maybe a set of pattern pads that are too thick?

 

[Kajjal]

Yes they are genuine pads and exactly the same as the ones they replace. Never had any trouble with the m785s and replacement pads. Possibly the caliper is faulty, would be my next guess.

 

[Kajjal]

Fixed it, i am guessing the new pads were thicker than the oem ones.

I just undid the cap on the shifters, pushed the pistons back, cleaned off the small amount of brake fluid released and reassembled as normal. Pad to disc gap is now similar to my xt brakes.

Braking is fine. Will test on longer ride to wear in brakes. May need another slight adjustment.

Thanks for everyones suggestions.