Pitting in cups and cones - any tips?

[Thias]

That German guy does have a nice fix, although I'm sceptical because the bearing isn't really supported by much of an edge on the inside and it appears to be a regular bearing rather than a tapered one. Wheels generally use tapered bearings because those are much better at dealing with sideways forces..

That sideways support would be an easy build. Just add a long spacer inbetween or use a nut. (If there is enough space inside the hub, that is.)

The guy writes in his text, that he used the standard bearings to test the principle of his idea. And if it worked, he would switch to tapered bearings. Those seem available in identical size.
But I dont really think this is a problem, really. For example, Piaggio scooters (I have a Sfera 50cc) have the exact same bearing (6002) in the front wheel. And those hold up 10000km or more. They do have a spacer inetween the inner races. But I rode about 8000km without that spacer inside, as the former owner seemed to have forgotten it :roll:

And then there are the uncounted that also use non tapered standard bearings, like AC, White Industries...

 

[xxnick1975]

That's a impressive annual mileage on an old mtb, hats off!

 

[focomat 1c]

Re:

Earlier this year I rebuilt some Shimano M-735 pedals with new ball bearings. The correct size was not available so I used the next larger available Imperial size. There was a very small increase in diameter which meant that the balls were in contact with a 'new' section of the hardened track surfaces. The pedals are working fine

Could you fit slightly oversize ball bearings to your hubs with the same benefits ?

It would be worth measuring the 'correct' bearings and seeing what is available in a slightly larger size, though you might have to use one less
ball bearing when assembling the hub

Just a thought

 

[Raging_Bulls]

Turns out that The Cycle Clinic still had a NOS 732 rear hub in 32h at a good price (£45 incl shipping), so I ended up buying that.
It's a 130mm OLD and I need 135mm, but that's not a problem because the only difference is a 5mm spacer and a 5mm longer axle really.
I have the longer axle and the spacer from my old hub, so all I need to do is put the new axle's cones on the old axle and that's the entire rear hub sorted.

That leaves me with the front. I guess I could use that for a little while longer, the pitting isn't that bad there. If only I knew how to get the cups out (there's no edges for anything to grip onto), I'd go with modern sealed bearings like that German guy did.
Perhaps I could put the hubs in the oven for a while, after all alu does expand more than steel. That might loosen up the cups.

 

[Muddy paw]

That's great news about the rear hub so that will last you a good while then when fitted ..

Fitting new bearings in the front hub seems alot easier then doing the rear and although i've never baked a hub before i can't see any harm by doing so as long as you don't over cook it , it should be fine as i've known others do it with car lights before now at 180 degrees so i'd give it a go in the oven for no more than 10 minutes ..

 

[The Bear]

Re:

Wheels generally use tapered bearings because those are much better at dealing with sideways forces.

Car wheels maybe and built to minimum cost bicycle wheels. None of my bikes have them and I've never seen a modern motorbike with tapered bearings on either wheel and thats because there're rarely any sideways forces. Apart from slow speed manoeuvring all weight/force acts radially regardless of lean angle and braking/accelerative forces.

The spacer in between the inner races is mainly to prevent QR or wheel nut forces from putting excessive sideways (clamping) forces on the bearings which will cause them to fail prematurely. What sideways force does exist I wouldn't worry about.

The only place you need tapered bearings or angular contact ball bearings on a bike is in the headset as the forces are a mix of axial (weight transmitted throughout the frame) and radial (braking).

 

[Thias]

You can get the cones out of the hub body by welding a few spots onto the cups on the inside. That will shrink the cups just a little bit so they just fall out.

 

[Raging_Bulls]

Re:

The new rear hub arrived.
The first one got lost in the mail (The Cycle Clinic sent it with tracking, but they somehow never even got the tracking info), so they sent me a new one right away. If you are reading this, Malcolm, thanks again! Excellent customer support.

I purchased some "6000RS" bearings for the front hub. Haven't been succesful in getting the old cups out yet.
I tried submerging the hub in boiling water for half an hour in the hope that it would be enough, but the temperature wasn't high enough to loosen up the cups yet.
I'll probably have them removed by a machine shop, those guys do have all kinds of tools that I lack. I need to get some spacers and stuff made anyway to get the bearings to fit on the original front axle.

That being said, the Scott's annual mileage is rather high and it'll only get worse as I plan to use it for traveling as well, so I'd much rather have the original cup & cone setup. Press-fitting new industrial bearings is not something you can do by the side of the road in the middle of nowhere.

So for now the old front hub has become a long-term project and I'm looking for a NOS M730 front hub in 32h fashion to go on the Scott.