Rear wheel locking up

[supersteve]

HI there , I hope someone can help me, I am fairly competent at repairing/maintaining my bike but this one has me and the local mechanic puzzled !

I was out for a ride when the back wheel locked up, I tried to fix it at the road side with no luck, took it a local mechanic who worked out the cones had locked up and stripped the axle he replaced the axle and cones, reassembled and all seemed well on the rack, however I rode away from the shop and a mile down the road exactly the same thing happened ! I need to know what is causing this as I am of on a long tour in 2 weeks. Bike is a TREK 7.5 hybrid and has given me years of trouble free riding, Things that have changed recently are. New chain fitted but not new sprockets, I have started riding with cleats,

I have a rack that attaches to the seatpost and just above the dropouts, I have moved the seatpost up while the rack was still attached.
any ideas will be gratefully received.

also I had a slight crash the day before, I fell sideways due to getting used to cleats, but got straight back on and bike was fine all the rest of that day and half the next day before this happened.

Thanks

[DaveM]

Just a guess, but it may be that the bearing race on the rear hub (the cup pressed into the hub body) is damaged. The shop should have caught that when they replaced the axle, but sometimes there can be tiny cracks that open under load, but hide themselves when things are taken apart. At least take the wheel off the bike and spin the axle by hand to feel if there's any roughness.

None of the other stuff you mention should have any effect. Except if your little crash made the wheel rub on the frame...

[supersteve]

(05-22-2012, 01:11 PM)DaveM Wrote:  Just a guess, but it may be that the bearing race on the rear hub (the cup pressed into the hub body) is damaged. The shop should have caught that when they replaced the axle, but sometimes there can be tiny cracks that open under load, but hide themselves when things are taken apart. At least take the wheel off the bike and spin the axle by hand to feel if there's any roughness.

None of the other stuff you mention should have any effect. Except if your little crash made the wheel rub on the frame...

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Thanks Dave, sounds like you might be onto something there, The guy I took it to works in a community bike shop and no offense to him but he was only doing minor repairs and adjustments for no charge so may have missed this possibility. I have taken the wheel off but it wont spin at all.
The wheel was definitely not rubbing as I rode a good 20 miles before this happened,and all looks straight and true.

Do you think my increased amount of riding over the past few weeks may have had the effect you mention? I have been over some pretty rough terrain ?

[DaveM]

This kind of damage usually isn't caused by hitting a bump as much as riding with a bad bearing or with the axle way out of adjustment. But hard to say really. Get it checked out. It could just be that a bearing failed or something else fairly minor. If it is the bearing cup, you may need a whole new hub/wheel.