Brake caliper out of position?

[RoubaixCube]

Not too sure if this is a common problem but over the past month ive discovered that my rear break on fairly new Cube Attain Race GTC keeps going out of position and pushing the right brake pad into my rims causing various levels of resistance if not stop it free spinning completely.

Ive spent the better part of the hot weather we have had here in london over the last month making a few changes and using the bike on the commute to test the changes. While my fixes would work for 15-20mins it would always end up the same way.

I took the bike into ChainReactionCycles on the way to work one day and one guy had a look at it for me. He adjusted the position of the caliper and told me not to break so hard. Sadly he couldnt do any more for me as the tech there was fully booked for a good few days and i couldnt leave with my bike with them as i needed to ride it home. He also suggested that if the problem keeps happening then i could book the bike for a tech to have a look and he would trim the black sleeving to the rear caliper which he thinks is causing the problem.

I took my bike back the next day and spoke to another person at CRC as the original person i spoke to before wasnt working that day, and explained that i was still having the same problems and the guy i spoke to yesterday suggested i trim the sleeving a little. This guy straight up told me that trimming it would be the wrong thing to do and wouldnt solve the problem so i was completely lost.

Im no expert on this - Ive tried tightening the caliper to the frame a little more and the guy at CRC did the same thing and said he would not tighten it any further. Regardless of what i do - the caliper still goes out of whack.

Im one leg away from taking it down to my LBS and have them look at it but If i can solve the problem myself then thats what id like to do.

Anyone have any suggestions?

 

[sight-pin]

Could it be one of the brake blocks not set right so it's pulling the caliper out of position?

 

[RoubaixCube]

Could it be one of the brake blocks not set right so it's pulling the caliper out of position?

Not as far as i know, Its ultegra so the the little 'shark fin' (as i call it) is always pointing downwards and ive made sure that the pads are aligned correctly with the rims when braking.

Another thing i forgot to add, The first guy told me i should 'brake-lightly' as in apply less pressure when braking but thats not possible when you're 16 stone and racing down a descent at 30mph.

It seems that the black sleeve that cable is routed through is 'pulling up' the the caliper to the left which pushes the right brake pad into the rim.

I also had my LBS check the bike over when i finished putting it together out of the box just to make it 100% sure it was safe to ride.

 

[Tojo]

have a look at this

http://si.shimano.com/#seriesList/38

Then download DM-BR0003-07

on the first heading BR-6800
http://si.shimano.com/php/download.php?file=pdf/dm/DM-BR0003-07-ENG.pdf
And look at page 12 & 13.....Hope this solves the problem.....

 

[RoubaixCube]

have a look at this

http://si.shimano.com/#seriesList/38

Then download DM-BR0003-07

on the first heading BR-6800
And look at page 12 & 13.....Hope this solves the problem.....

No help at all - Ive already mentioned that i spent at least a good two weeks adjusting it manually myself with no positive outcome. its no good learning how to 'center the caliper if the cable is going to pull it out of position anyway -- which happened on every occasion.

 

[summerdays]

Not that I'm going to be the person to solve this problem but photos might be helpful?

 

[Ajax Bay]

I think an image would help, too, so we can gain insight to the CRC 'too long outer' diagnosis, if nothing else. The cable outer ('black sleeve') should display a shallow arc to the locking nut on the brake without bending 'up' first. What is the diameter of the 'black sleeve' in mm, ie the bit from where the cable comes out of the top tube? Assume the brake calipers are secured with correct torque to the frame. This through bolt/nut fastener should provide enough friction to stop the symptom you describe.

 

[sight-pin]

Found this on bikeradar, looks like the guy was having the same problem as you, scroll down to bottom, looks like he cured it with the advice given.
http://www.bikeradar.com/forums/viewtopic.php?t=12974360

 

[mjr]

I've more hub, V and even old side pull brakes, so I've not fiddled with one for a while, but do dual pivot calipers need balancing with small screws as well as centering? And is the pivot lubricated and moving freely?

 

[Ajax Bay]

do dual pivot calipers need balancing with small screws as well as centering?

He's done all that (I think the OP's posts above establish that). The relatively small force of the inner against outer push movement (when the brakes are applied) seems to be greater than the resisting frictional force of the through-bolt securing the brake calipers to the frame. Alternatively it is possible the knurled nut keeping the two calpers together has worked loose. I'd take the calipers of the frame, clean them (given the opportunity), check that the knurled nut is firmly tightened against the washer and then refit, to the torque specified by Shimano.

 

[sight-pin]

Alternatively it is possible the knurled nut keeping the two calpers together has worked loose. I'd take the calipers of the frame, clean them (given the opportunity), check that the knurled nut is firmly tightened against the washer and then refit, to the torque specified by Shimano.

I think that's what the problem was in the link i popped up?

 

[mjr]

He's done all that (I think the OP's posts above establish that).

I'm not seeing that. The closest I see are comments about adjusting the position of the caliper (could be as little as pushing it) and having spent a long time adjusting it. It sounds like a stuck pivot BICBW.

I'd take the calipers of the frame, clean them (given the opportunity), check that the knurled nut is firmly tightened against the washer and then refit, to the torque specified by Shimano.

Good idea anyway because cleaning, lubing and checking the fitting from scratch could fix a range of problems.

 

[Broadside]

My wife's bike had this problem from new. We tried trimming the sleeve which made no difference.

I posted the problem on here and was told to keep on tightening the 6mm hex socket on to the frame, but estimated it was already at about 10nm so didn't want to go further as its a carbon frame etc.

We kept taking it back to the shop where we bought it and they were puzzled by it but kept tightening it a little more and it seems to have stopped now. I'm guessing it must be torqued up to around 15nm, much tighter than I would have been happy doing myself on a carbon frame, but it seems fine now.

 

[raleighnut]

I've more hub, V and even old side pull brakes, so I've not fiddled with one for a while, but do dual pivot calipers need balancing with small screws as well as centering? And is the pivot lubricated and moving freely?

Dual pivot (modern ones) have a single 'balance' screw.

 

[RoubaixCube]

Already balanced the caliper and ive done it constantly over the past two to three weeks. Maybe i should just use the front brake a little more when cycling on the bike but ive noticed that even if i do brake lightly or try to stay off the rear brakes as much as i can the same issue still occurs but not as bad - pad still makes contact with the rim but the wheel is still able to spin though there is a little resistance so it wont spin for long if you just lifted the back of the bike up and spun the wheel by hand.

the bike has been sitting indoors for a week now while i try and come up with a solution to my problem. The final straw was when the rear rim was quite warm to the touch after being in constant contact with the right brake pad.

Calipers look balanced - Ive adjusted them over the last few days and tweaked them each time ive went to make a cuppa tea. Wheel is spinning freely but give it 15mins down the road and it will be making contact again.