Replacement bearings for On-One track hubs

[drossall]

Wow, thread necromancy squared! Rather apposite, in fact, as I've just, eight years on, replaced the bearings again, with the spare set that I bought last time round. For some reason, and remembering that (obviously) I had done it before, it was one of those really frustrating jobs where only Park Tools really benefit.

Everything went wrong. The old bearings wouldn't shift, and I over-hit the axle-end, with a track nut on it to spread the load. So the threads took a little damage. Then the new bearings wouldn't seat. I was using the old bearings and the track nuts in a make-shift press, and ended up with one track nut locked onto the axle. The usual trick of locking up two nuts on the other end wouldn't work, and I had to buy a Park Tools axle vice to free the nut up. That was just the last in a series of locked-up nuts that I did manage to free. I also bought a nylon support bush for the hub, to spread the load when tapping bearings in. I'm still not that happy with the result, the new bearings run a bit rough, and one cartridge (remembering that they're identical from the same purchase) seems to sit a bit proud compared to its predecessor. Took hours for a dud result, but it's a winter fixed so it will have to do

I replaced them in part because I'd creaked my way round one ACME event, and I knew that they were due for replacement, as was the BB cartridge. But, even after all that, I still creaked my way round the next  I think it was actually the cranks and chainring moving - even though they were no longer even on the same BB

Some jobs just seem doomed

[Brucey]

IME there are plenty of hubs out there where the bearings are a fit that is too tight by far. I have even taken to grinding the bearings down before they are fitted in some cases, else they have way too much preload on them when installed.

In theory you can buy bearings that are correct tolerance for the exact fit of the hub, but identifying that is not easy and sourcing the bearings ain't easy either.

If correctly specified and installed, with lots of good lube, such bearings ought to last for tens of thousands of miles. That they don't is for exactly the same reasons as cup and cone bearings can clap out too; they were never set up right and/or lubricated properly, and/or the water got in.

cheers

[zigzag]

checked my bearings (of similar hubs) today and in the rear hub they are not entirely smooth, will replace them in a couple of months. the wheels will have covered 7000km, mostly in damp winter weather.

[drossall]

IME there are plenty of hubs out there where the bearings are a fit that is too tight by far.

Although the odd thing is that I bought several sets, and this was the second of those that I had fitted in the same hub. The first set went in fine.

[Brucey]

IME there are plenty of hubs out there where the bearings are a fit that is too tight by far.

Although the odd thing is that I bought several sets, and this was the second of those that I had fitted in the same hub. The first set went in fine.

That is a bit odd.  Mind you temperature makes a difference (might be worth trying a kettle full of boiling water) during installation, even if it doesn't affect things in quite the same way once everything has cooled down. Also the bearing seats can get marred/corroded.

  Another thing which can happen is that the spacing of the bearing outers does not match the bearing inners exactly; eg if the axle has shoulders on and the bearings cannot be driven quite far enough into the hubshell there will be an axial preload. Some hubs are designed to be adjustable like this, but if you want to you can pack the shoulders on the axle with thin shims and that way the hub won't be adjustable any more. The other way is to grind a little off one of the bearing outers. Often a tap on the axle with a soft hammer, both ends, causes the bearings to 'settle' and be less bindy.

 A problem with keeping the bearings adjustable is that the inner isn't trapped any more and if it starts to spin (eg if the bearing starts to nip up with even the slightest corrosion) then it soon wears the axle.

Often when cartridge  bearings are brand new they are smooth enough that a monster preload is not readily apparent; however the slightest roughness on the bearing surfaces can cause the bearing to feel terrible. Often  when such bearings are removed, they mysteriously feel nice and smooth again.

Normally you can quickly/easily  bosh a new set of bearings and it'll last a year or two. But if you want the fitment to be perfect and long lasting, with the right grease and the correct  preload on the bearings and so forth, cheap cartridge bearing hubs are usually more trouble to set up than cup and cone hubs.  I can quite easily set up cup and cone hubs to ten microns or better, but with cheap cartridge bearing hubs that is just a dream.

cheers