Bicycle Mechanics - Rear axle/bearings always come loose soon after adjusting them

I have a non-quick-release rear axle, the kind where you screw the bearing cones along the axle into the hub from either side, with a locking nut outside of those, and you have to get them just about right so that with the additional tension from bolting the axle back into the dropouts, the bearings are held under a suitable tension and the wheel spins freely but doesn't wobble.

My problem is that after, I don't know, a few 10's of miles at the most, the wheel always becomes really loose again. I can hold the wheel and wobble it significantly, relative to the axle. That is to say that the interior of the hub, the bearings, and the cones on the axle, are no longer being all held tightly together.

I hope that all makes sense...

It causes no problems when riding, but I worry it will be damaging the bearings or something.

How can I stop it always coming loose like this?

Thanks

sound like you need a new axle, there maybe a problem with the treads.are you sure you are locking the locknut to the cones on both sides.try locking the drive (right) side first,then adjust the left side cone for the right adjustment and lock the locking nut to it.are you sure the axle is not broken?

are you using cone wrenches? if not , you need to

+1 on the broken axle /stripped threads theory

Also,if your repacking the bearings,you need to squeeze the grease out from under the balls.Otherwise,it will move when it rolls and you will have a little clearance when it settles in.

That's why the best procedure is to tighten the bearing until it is a bit too tight (which you test by spinning the wheel or the axle), then loosening it. But I don't think that is the OP's problem.


Another possibility is that the whole assembly is shifting in the dropouts and unscrewing the properly jammed cone/locknut assembly. Are the surfaces where the retaining nuts sit worn or irregular? If so you have a much bigger problem than the easily replaced threaded parts.

There's less likely to be damage with a bit too much play in the bearings, rather than too little. This is a real puzzle. When tightening up the second cone, are you making sure that all the ball bearings have settled into position properly, before tightening the locknut? When this play has developed in the wheel after riding, is the wheel still held tightly in the dropouts?

Remember, the OP said that the preload is changing as he rides.

If nothing is shifting (moving about), I don't see how this can happen, even if the initial setup is incorrect. There's nowhere near enough torque transmitted through the bearing from the wheel to move the NDS cone against the jam formed by the dropout and retaining nut. (I'm less clear on the DS cone.) But if the assembly is shifting, that could easily do it.


rock_ten, you're awfully thin on specifics. Is the rear cluster on a freehub or freewheel?

New Posters - please READ THIS (http://www.bikeforums.net/showthread.php?t=338432)

...so that with the additional tension from bolting the axle back into the dropouts, the bearings are held under a suitable tension and the wheel spins freely but doesn't wobble. The axle should be adjusted without wobble before being bolted into the frame. Bolting a solid axle to the frame does not increase tension on the center section.

Adjustment does change as cones break in. I bet you get the cheaper ones which have black oxide on the entire surface along with a bunch of tiny nicks as if they'd been in a large bin then poured down a chute into a shipping box or something. If you take one of those apart after a few dozen miles they can be seen to develop a shiny wear land.

I have read several references which said that you have to check cone adjustment a few times after a repack and then readjust.

It is also true that some bearing balls do not stay round but become slightly egg shaped. You may not install them on the low spot but they find it after a few dozen heavily loaded miles. So always use new balls.

take the wheel to your lbs and have them adjust the cones. mounting the wheel should have no effect on the cone adjustment. I think your technique just needs practice because the retaining nut and the cone should be tightened against each other. maybe some online videos can help explain

Whatever the problem, make sure a full sized washer goes between the cone and the nut.
:thumb:

Are the cones loose when you remove the wheel (after riding a few 10s of miles)? If so, maybe threads are stripped or you're just not tightening it properly.

Seems like if this was a matter of non-round bearings, the problem would show up after i.e. a mile, not dozens.

Thanks for all the replies and advice - I'll see if I can put it into practice and I'll let you know what happens.

Here are some specific responses:


Another possibility is that the whole assembly is shifting in the dropouts and unscrewing the properly jammed cone/locknut assembly. Are the surfaces where the retaining nuts sit worn or irregular? If so you have a much bigger problem than the easily replaced threaded parts.

You mean the outer surfaces of the dropouts, basically? If so, then no, they're flat and don't appear to be worn.


are you sure the axle is not broken?

I don't know, I guess


are you using cone wrenches? if not , you need to

No, I can easily make it way too tight just with my fingers, so I haven't bothered getting any cone wrenches. What will be the benefit of using them?




Another possibility is that the whole assembly is shifting in the dropouts and unscrewing the properly jammed cone/locknut assembly. Are the surfaces where the retaining nuts sit worn or irregular? If so you have a much bigger problem than the easily replaced threaded parts.

You mean the outer surfaces of the dropouts, basically? If so, then no, they're flat and don't appear to be worn.



> When tightening up the second cone, are you making sure that all the ball bearings have settled into position properly, before tightening the locknut?
> When this play has developed in the wheel after riding, is the wheel still held tightly in the dropouts?

> erm, not particularly, though I'd imagine it would be very noticeable if the bearings weren't settled down? The cone surely wouldn't screw in properly at all.

> yes it stays held tightly in the dropouts.




rock_ten, you're awfully thin on specifics. Is the rear cluster on a freehub or freewheel?

Sorry - I didn't know what was relevant or not. I have a freewheel, 5 speed, and it's some standard shimano one. The hub, axle and bearings all came with the bike when I got it, and the bike itself is about 30 years old. I have stripped and repacked them once, a couple of years ago.



Are the cones loose when you remove the wheel (after riding a few 10s of miles)? If so, maybe threads are stripped or you're just not tightening it properly.

Seems like if this was a matter of non-round bearings, the problem would show up after i.e. a mile, not dozens.

Yea they're loose after that time. Loose in the sense that if I hold the axle and, say, the rim of the wheel, I can wobble them relative to each other.

I don't know when it shows up - it might be almost right away. Next time I adjust them I'll make sure to check after a short ride.

Thanks for all the replies and advice - I'll see if I can put it into practice and I'll let you know what happens.

Here are some specific responses:



You mean the outer surfaces of the dropouts, basically? If so, then no, they're flat and don't appear to be worn.



I don't know, I guess



No, I can easily make it way too tight just with my fingers, so I haven't bothered getting any cone wrenches. What will be the benefit of using them?





You mean the outer surfaces of the dropouts, basically? If so, then no, they're flat and don't appear to be worn.




> erm, not particularly, though I'd imagine it would be very noticeable if the bearings weren't settled down? The cone surely wouldn't screw in properly at all.

> yes it stays held tightly in the dropouts.




Sorry - I didn't know what was relevant or not. I have a freewheel, 5 speed, and it's some standard shimano one. The hub, axle and bearings all came with the bike when I got it, and the bike itself is about 30 years old. I have stripped and repacked them once, a couple of years ago.




Yea they're loose after that time. Loose in the sense that if I hold the axle and, say, the rim of the wheel, I can wobble them relative to each other.

I don't know when it shows up - it might be almost right away. Next time I adjust them I'll make sure to check after a short ride.

Try this......

With the wheel mounted and tight, grab the dropouts (where the nuts that hold the wheel on the bike fasten to) and try to pull them apart. That is to say, facing the bike from the back, grab the bike frame right where the nuts on the axle fasten, and pull so you are trying to spread the frame apart from the wheel. If the frame flexes, the axle is broken.

Thanks for all the replies and advice - I'll see if I can put it into practice and I'll let you know what happens.

Here are some specific responses:...No, I can easily make it way too tight just with my fingers, so I haven't bothered getting any cone wrenches. What will be the benefit of using them?You hold the cone IN PLACE with the cone wrench and tighten the locknut against it (or against the spacer that goes between the cone and locknut.) It keeps the cone from getting too tight.

When you get your new cones and bearing balls, set them against the bearings so that when you twirl the axle in your fingers, you feel solid contact but no rotational drag. Make sure you can't feel the axle move from side to side at all, but set it so there is no more pressure than you need to achieve this situation.

Don't worry about finding new bearings in a cage, unless you want to. Wash your hands of all grit, put some grease in the cups, and stick nine loose 1/4" balls in. Then put the cones on.

Read parktool.com or sheldonbrown.com or get a book on bike repair from your local library. Find out what pitted cones or cups look like. You probabaly have them.

If pitting has started, even a little bit, it means the metal has fatigued and it is sure to spread very quickly. The hard chips will ruin the cups if they're not already shot.

Park Tool makes a series of good, double-sided cone-wrenches. These are pretty cheap and are available in most bike-shops. Everyone who is planning on doing their own wrenching should have these:

http://i424.photobucket.com/albums/pp323/nagognog/ParkTooldouble-sidedcone-wrench.jpg