Rear Bike Wheel Won't Set In Dropouts...

milehigh

So I've got a Marin 29er. I've had it for a few months, put say 75 miles on it so far. It's got disk brakes, hasn't been wrecked and is in good shape.

So yesterday I went and removed the wheels to transport it in a car. I get home and the front wheel goes on just fine, but the rear wheel will not set into the dropouts! I spent 20 minutes trying to get it set (playing with the derailur/ chain, checking the brake) before going online to make sure I wasn't missing something. I then tried for another 15 minutes before giving up. It seems to be 1-2 cm from actually getting in. I've got the quick release skewers, and I unscrewed them nearly all the way to ensure that wasn't causing problems.... I read that deflating the tire could help (I didn't have time to try) but I can't really understand why That'll be my next step before conceding defeat and going to my local bike shop.

Anyways I'm at my wits end and hoping somebody here can shed some light on this or maybe let me know if there's something else I should be checking. I wanna ride my bike!

saltiness

Does it have disc brakes? Are the pads stuck together?

mts

yea sounds like the brakes are preventing them from sliding in all the way. you are putting the wheel on the correct orientation right

milehigh

It does have disc brakes, but from what I can tell they have adequate room to seat. If they were stuck how would I go about UNsticking them?

schuss

milehigh wrote:

It does have disc brakes, but from what I can tell they have adequate room to seat. If they were stuck how would I go about UNsticking them?

You have to open them up and bleed them out. It sucks. keep a piece of plastic or cardboard to slip in there when you remove it.

milehigh

To the bike shop it is!!!

Gruffalo Soldier

Do you know if the disc brakes are hydraulic or mechanical?

If you can see a metal cable attached to the brake mechanism at the back they are likely mechanical. See: http://www.pricepoint.com/images/styleimages/D_115%20AVDMD3.gif

If the cable is sealed all the way from the brake lever to the mechanism at the back, they are likely hydraulic. See: http://www.comparestoreprices.co.uk/images/sh/shimano-deore-m535-hydraulic-disc-brake-kit-fully-assembled.jpg

Mechanical and hydraulic disc brakes differ in that if you depress the brake lever when the rotor is not within them (i.e. when the wheel is removed), a mechanical brake will spring back a far as the cable securing it will allow, while hydraulic brakes will 'stick' together as there is not sufficient force to push the fluid back. The brake lever could quite easily have been knocked as you were putting it into or out of the car.

If they are mechanical, you should be able to get the two pads apart (if they are indeed stuck and that is the problem) by sticking something flat in between them; plastic is preferred to avoid damaging the pads, but a flat head screwdriver or knife will do if you are careful. The pads have magnetic patches on the back so they should 'spring' back into their proper position with a little bit of fiddling. Alternatively, you can slacken / release the cable at the brake mechanism by loosening the nut holding them. This will allow the brake pad holder to retract further and give you some more wiggle room.

I have no experience with separating hydraulic pads, but from http://forums.bicycletutor.com/thread-269.html, the process is similar. Note that here you are pushing the pad holders back, rather than the pads themselves.

If you have only had it a few months, and you don't mind waiting to take it to the shop the best course of action is probably just to take it back and ask them if they will do it for free. A good bike shop should definitely perform a task like this so shortly after sale for free. For extra XP, ask the mechanic to show you what they are doing so next time it happens you can fix it yourself!

EDIT:
Note that if prising apart hydraulic brake discs a plastic implement is a must as you will be exerting more force on the pads and therefore are more likely to scratch them if using metal.

japan

Two simple things to check before you go bleeding the brakes or anything:

Are you correctly routing the chain? The rear derailleur will fold back on itself when you take the wheel out. It's possible to get into a bit of a tangle if you catch the wrong bit of chain on the cassette as you put the wheel back in.

Are the dropouts cowled or lipped? They're sometimes designed that way so that an incorrectly tightened quick release skewer will not result in the wheel falling out of the dropout (although it's more common on forks). It also means that if you haven't backed off the nut on the end of the skewer enough the wheel will not seat in the dropout. If in doubt, unscrew and completely remove the skewer before trying to seat the wheel.