Rotor rub - hub related??

[outtacontrol]

I have a Trance with low spec Shimano M486 hydr. brakes with a Deore rear hub. I get rotor rub while out riding, but when I check back at home, the alignment is perfect.

It only seems to be after braking or smashing a downhill.
Could the problem be related to the hub needing adjustment?

There doesn't seem to be any sideways play in the back end. How do you know if the hub needs adjusting?

 

[leftieant]

Interesting.

Hub play - could - be an issue, but more likely scenarios. You'd know if the cones were loose as there would be sideways play in the wheel while in the bike.

Are the Shimano brake single piston or dual (ie do they clamp from 1 side only or from both)? If they are a single piston, they work by physically pushing the disc over to meet the other pad, which is fixed.

If you're only noting it it when the brakes are in use / hot, it could also be the discs heating up and warping.

Really depends how much it is annoying you and how much money you want to throw at it as to what sort of solution you employ.

 

[outtacontrol]

They are dual piston hydraulic brakes. I have had the bike for a year and never had any issues.
Occasionally, I get some rub, but adjusting the callipers always sorts it. This is why this rub is killing me, it is only intermittant. It will rub really loudly all of a sudden, and then just as suddenly it will be gone.

The rub will appear without lots of braking (rotors wouldn't even be hot). I thought that maybe one of the pistons may have been sticking and not returning fully, but the rub will happen after a bunny hop landing with no braking.

 

[frensham]

How worn are the pads? I have found with my Hayes brakes that when the pads are nearing their wear limit they tend to 'float' around a bit and occasionally rub annoyingly. The nest time they rub try squeezing the lever just a bit without actually applying the brakes - if the noise goes away this is probably your issue. I only ever get brake rub when the pads are well worn. Hope this helps.

 

[outtacontrol]

They are resin pads that are supposed to wear quickly. I have used them for a year so would be close to their limit.

I don't understand how that would effect them rubbing. The spring clip would work the same, regardless of pad wear, I would have thought.

 

[akashra]

Sore, it could be. But it also tends to happen as the axles flex a bit and they shift out of position ever so slightly.

Also, have you re-aligned the calipers? Back off the screws, compress the brake, and with it still held in re-tighten the caliper to make sure it's centered.
Of course this is a pain on a 140mm rotor which doesn't use an adaptor :/
Wheels never go back in exactly the same way when you remove them, so their offset may change ever so slightly - enough to have that flex come in to play.

Happens all the time on my bikes.

 

[outtacontrol]

yeah, that is what I normally do. When this rub happens, when I get home and check, allignment with callipers is spot on.

The rub is loud and will start and stop while riding, as mentioned above, usually after braking or hitting a bump.

 

[frensham]

Have you checked the retaining springs? They might be broken......

 

[DuncanFG]

It's possible the axles are bent. One of my bike came with Deore hubs and the brakes drove me nuts. I'd get them perfect at home, take the wheels off to pack in a car, get to the trail and they'd rub. Every time I took the wheel in or out the axle would be in a different spot and the rotor would move.
The Deore hubs were pretty nasty, the axles bent and the spacers cracked. Upgraded to XT hubs and haven't had to touch them in over 4 years. Best hubs I've used/seen.

 

[danj]

I have just started getting this problem with my XT wheelset/XT brakes on an 09 Trance X1. Alignment is spot on when the bike is on the stand, but start riding it and at some point the noise will come, I notice it seems to be when I stop pedalling. If the noise comes, I can put the power on ever so slightly and the noise is gone.... Not sure if that last bit of info is a red herring, but I'd love to find out a solution to the problem. I'd say I have at least 1mm of 'meat' left on both pads and they are the original resin pads...

 

[dhd]

OK, I'm going to go out on a limb here. From what you are saying as far as being after braking and downhill, I reckon it may be heat related. Possibly the rotor warping from heat, but more than likely the caliper heating up and the fluid expanding in the caliper which pushes the pads in.
One way to check this theory is check the amount of pull at the lever at the top of the downhill and at the end. If the lever moves less, the brakes are pumping up from heat.

 

[Landon]

Brake Rub

Yeah, your brakes might be pumping up as DHD said.

You can also try:

Make sure your rotor bolt/bolts are tight

If your pads are getting towards to end of their life, check to make sure they're not wearing like a door stop. This can cause the pistons to bind up, especially on Shimano brakes. Replace the pads if they're not wearing nice and parallel. With a Shimano brake, you'll need to have your brake mount faced.

Make sure the caliper pistons are centred and that both move freely. It's quite common to find a Shimano brake with a sticky piston. It can be an on and off issue and will sometimes cause the rotor to make contact with the caliper body if one piston refuses to move. If this is the case, you should remove the pads and clean the caliper with water and a tooth brush to remove any junk. Apply a small amount of Shimano mineral oil to the piston and pump the piston in and out of its bore a few times with a plastic tyre lever.

 

[Raf]

I would hazard a quess that your wheel is not on tight enough. Under power and under shock (jumps etc) it moves up and down in the brakets.

Is it possible you could tighten the wheel abit more?

Also check for dirt in the bracket or a cracked bracket on the frame.

Just a guess, but I had a road bike whic would move the wheel whenever I mashed the pedals hard.

Raf

 

[Mr Green]

One more thing to check and I could be wrong is that there is a tad too much fluid in the brake system. When it gets hot it expands just enough for the pad to rub but when it cools back home in your shed they sit perfectly again.

 

[bear the bear]

Bike checking 101:

Step 1. Swap wheels with a mate go for a ride compare notes for noise.

Step 2. If it's the wheels start checking here, QR, axles, bearings, rotor bolts.

Step 3. Brake related. Check pads, springs, adapters, bolts and Bleed brakes.

 

[DbD]

Could also be that you've got an intermittently sticky piston that doesn't always retract. When it rubs on the trail have you examined it to see how its rubbing e.g. one side, both sides, other...??

 

[Old Shagger]

Me 2

I have just started getting this problem with my XT wheelset/XT brakes on an 09 Trance X1. Alignment is spot on when the bike is on the stand, but start riding it and at some point the noise will come,

And i have the same issue with my XT wheelset/brake Trance X1 09 as well. My bike has only done 100kms and on a cycleway(as i am just coming back from big injury). I was putting the annoying rub down to my larger than most weight causing flex....
Mine does it along a flat cycleway, so no brake heat at all, and it is totally intermitant and annoying. My pads are obviously brand new as the whole bike is.......so go figure???

 

[outtacontrol]

And i have the same issue with my XT wheelset/brake Trance X1 09 as well. My bike has only done 100kms and on a cycleway(as i am just coming back from big injury). I was putting the annoying rub down to my larger than most weight causing flex....
Mine does it along a flat cycleway, so no brake heat at all, and it is totally intermitant and annoying. My pads are obviously brand new as the whole bike is.......so go figure???

I feel your pain. My rub has been missing for awhile, so fingers crossed.

I only weigh 60kg, so don't think the weight flex is the cause (at least not in my case)

 

[danj]

It's still there, the pistons appear to be working OK, so I might try a set of new pads to see if it helps....

For those doing the Otway this weekend, sorry in advance if my brakes give you the sh*ts. If the new pads don't help I'll throw an old mavic wheel on and see if it makes a difference.

Cheers,

Dan.

 

[Bjorn]

If you are changing pads or just cleaning up calipers, get a can of brake cleaning spray. It's a low flash point solvent (very flammable) which leaves no residue.
When I clean calipers, I like to pump the pistons out a little farther than they are with the disc in the middle and then clean off the ring of hard grime that builds up around the piston where the seal sits. If you push that ring of grime back past the seals you risk damaging them.
You can also use the spray to clean any contamination/crap (visible or not) off your rotors.
With your calipers nice and clean you can go about setting them up, knowing they should not be binding or doing any other annoying stuff.