Back Wheel Keeps Going Out of Alignment

[JtB]

When travelling over particularly rough terrain, the alignment of my back wheel seems to change slightly such that the disc starts to rub against the disc brakes. As a consequence I'm having to stop quite regularly to re-align the back wheel. The quick release mechanism on the wheel itself is as tight as I can make it and the disc brake mountings are also tight.

Anyone seen a similar problem? And is there a solution?


Shaun.

 

[Steve Austin]

it can happen for a variety of reasons, more so on mtb's as they get bumped about.
biggest culprit, ti skewers or poor skewers.
ti skewers flex so can allow wheel to jump.
the best vfm skewers are shimano. they are the best for the cash and can be bought real cheap on ebay or stw

your wheel shouldn't be jumping if the skewers are tight

 

[Cubist]

When travelling over particularly rough terrain, the alignment of my back wheel seems to change slightly such that the disc starts to rub against the disc brakes. As a consequence I'm having to stop quite regularly to re-align the back wheel. The quick release mechanism on the wheel itself is as tight as I can make it and the disc brake mountings are also tight.

Anyone seen a similar problem? And is there a solution?


Shaun.

Is it a new bike? Have you recently changed the pads? My guess is that the calipers need centering on the discs. You say the mounting bolts are tight? Have you got them torqued properly? Overtightening the mounts can send the calipers out of centre. It could just be that the pads are bedding in, in which case you may have to recentre the calipers a couple of times before the rubbing stops. Some disc brake systems do this every few rides, in exactly the same way as your cables need tightening as your pads wear on v brakes, it simply becomes part of routine maintenance. Mine go out of true especially if I do a lot of steep downhill and get them hot.

 

[JtB]

Thanks both.

The bike is new. I tried a different skewer this week and took extra care centering the calipers on the disc. Went for quite a rough ride on the South Downs yesterday and I didn't have any problems with the bike.

Previously when I've centered the calipers, I've only had to lock the brakes a couple of times and the pads are rubbing again on the discs.

Not sure why a different skewer should make a difference, but anyway, lets see how it goes.

Thanks again.

 

[Mr Pig]

How are you centering the wheel?

You should not be trying to line the wheel up with the brake caliper. You should be making sure that the axle of the wheel is tight into the dropouts (slots in the frame). Then move the brake caliper to line up with the disk.

If the wheel is not right into the dropouts it will move. If it is right into the dropouts it almost certainly won't.

We had a Giant bike that had totally squint dropouts, the wheel was right off to one side if you put it fully home. I'll never buy a Giant bike again.

 

[JtB]

My bike is a Claud Butler and the user manual is next to useless. So the method I've evolved (rightly or wrongly) is to loosen the calliper mounting bolts, back off the brake pads completely and as you say make sure the axel of the wheel is tight into the dropouts. I then tighten up the brake pads against the disc such that the callipers are centred on the disc, tighten the calliper mounting bolts and then back off the brake pads again to give some clearance.

 

[Mr Pig]

That should work but not all brakes will centre up that way. Some push more from one side than the other. I think you're better doing it by eye.

It's unlikely the wheel is moving, it's probably the brake calliper. What kid of brakes are they?

 

[JtB]

Had a puncture this weekend and had to remove the rear wheel. Then all the problems with the wheel alignment started again. But I think I've finally found a technique that works. After setting the wheel and aligning the calipers (as per above), I then need to ride the bike for a few miles and re-align the calipers. Once I do that it seems to sort itself.

 

[Globalti]

Something is wrong as you shouldn't need to do this.

Are you sure both brake pads are moving freely and equally? Remove the wheel and gently squeeze the brake lever then watch as the pads move - do they move equally or is one sticking or even jumping out and staying? The movement you see is in the flexibility of the piston seals but if one piston is actually able to slip slightly through its seals it will stay in the new position and rub on one side. You could probably resolve this by stripping the calipers, giving everything a good clean and even polishing the pistons then reassembling, fitting new seals if necessary. If you haven't done this for a year or so the pistons will be clogged up with grey mud and pad dust and will need servicing anyway.

The second possibility is play in your wheel bearings.

 

[JtB]

The bike is only a few months old and it doesn't seem to be a problem with the brake pistons/pads. After riding the bike a couple of miles the disc can be seen to be rubbing on the side of the caliper. I can only conclude that I'm unable (for whatever reason) to seat the wheel in its natural position and that I need to ride the bike for the wheel to find its own natural position.

 

[Globalti]

As I wrote, this is definitely wrong, the wheel should not move once the axle is seated in the dropouts and the QR tightened. How tight are you doing the QR?

 

[Jonathan M]

Is it a mechanical disc? If so, are the adjusters loosening as you ride, hence the need for adjustment? Would give the symptoms you describe, and I recall such uselessness from some ridiculosuly cheap mechanical discs I had many moons ago.

The fix on that IIRC was to use a zip tie to prevent the adjusters moving.

 

[JtB]

The QR is as tight as I can make it. Also, I didn't realise there were adjusters on the actual disc itself, I will take a closer look tomorrow. I think I'll also contact Mail Order Cycles (the supplier) to see if they can offer any advise.
Thanks all,
Shaun.

 

[billflat12]

wheel alignment

have you checked the axle ? on my old shimano fh475 rear hub the bearing support was insufficient and the axle got bent slightly, causing the problems you have.

 

[Globalti]

Is the axle BROKEN? It's not uncommon, it's happened to me twice.