Diagnose wheel problem

HivemindXX

I noticed the rear wheel on my MTB has a problem last night. It can move a few mm from side to side pretty easily. The cassette and all other parts seem to move but the wheel is firmly tightened in to the drops. It seems to me that the hub is loose on the axle.

Does that seem likely and if so is it something I can relatively easily fix myself?

I'm a bit puzzled since I've never seen this sort of problem with my regular bike and that one has generally lower quality parts and sees a HELL of a lot more use than the MTB.

ashleey

I think you need to tighten the cones of the wheel axle. They are effectively what holds the axle to the wheel. Too tight and you crush the bearings. Too loose and you get that wobble.

http://www.parktool.com/blog/repair-help#

http://www.sheldonbrown.com/cone-adjustment.html

Hope this helps

MarcinG

HivemindXX wrote: »

I noticed the rear wheel on my MTB has a problem last night. It can move a few mm from side to side pretty easily.

How many gears do you have or to be more specific what kind of freewheel do you have? in older types (non cassette ones used widely in cheap bikes) there is an uneven weight distribution problem as on the left bearing is supporting axe at the far end but left bearing is fitted just under biggest of you sprockets. Easiest thing to do is just to remove wheel from frame and turn axe around - if it goes up and down of right side then you axe is crooked and need to be replaced (worst scenario would be is already in 2 pieces which happened to me twice on my first giant mtb), if it looks straight just try to shift axe from left to right if it moves then you need to adjust the cones (but i would open hub to replace grease and see what is a condition of the races they may be damaged already). You may need some extra tools to perform all the steps.

HivemindXX

Thanks guys, both those posts were very helpful. I had a look at Sheldons (very useful as usual) site and tried the diagnostic tips Marcin gave me.

It's a Deore hub on an old (but underused) Merlin Malt MTB so I think the freewheel should be a fairly good one.

When I did as Marcin suggested I found that the axle was straight but it did move in and out. I was able to hand tighten the cones using the dustcover (having read Sheldons page I'm now an expert on hub anatomy ). This fixed the problem although possibly temporarily.

When I used the bike a few weeks ago I noticed that the disc brakes were binding a little on the rear wheel which looked like it was due to the disc not being centred in the caliper. I couldn't fix this (no spacers to remove on that side) so I ignored it and the problem went away. When I tightened the cone cover the brake binding came back so I suspect the root cause was the disc brakes gradually pushing the wheel out. The best permanent solution therefore seems to be to get the brakes serviced since they may have gotten a bang which caused them to lean in more then they should.

MarcinG

HivemindXX wrote: »

I was able to hand tighten the cones using the dustcover (having read Sheldons page I'm now an expert on hub anatomy ). This fixed the problem although possibly temporarily.

i would drop it to a mechanic shop so they will adjust both cones and calliper
as longer you use it in this condition bigger the damage i'm affraid.