Motobecane rear wheel bearing replacement

My never-ending 1977 50V Moby project needed a new set of rear wheel bearings. I did the job today, and thought I'd share the results.

First off, the bearings were a very common item. Standard #6200Z(Z) ball bearing. $5.82/ea from the local bearing supply house; about $12 total, including tax. This beats the online shops by a mile, which want $15/ea for the bearings, plus S&H.

The old bearings had a metal shield on one side, but open on the other. The new bearings had a shield on both sides - so this is an upgrade. I think the 'Z' suffix means a single shield, and ZZ means two shields.

Put a little propane heat to the hub, and the old bearings drove out easily. There were some metal shavings in the bores, from the original factory installation.. kinda sloppy. I cleaned the debris from the bores before installing the new bearings.

Coated the new bearings & bores with lanolin, and drove them in with a socket that was just slightly smaller than the outer diameter of the bearing. Lanolin has a very high film strength, and is excellent for assembling things with interference fits.

Maybe someone will find this info useful.

Re: Motobecane rear wheel bearing replacement

Yes thanks. I've been considering doing the same, and I am more likely to do so now.

Re: Motobecane rear wheel bearing replacement

how do you know if you need new bearings,?

Re: Motobecane rear wheel bearing replacement

bandit,

In my case, I could hear and feel some roughness when I was riding it. I pulled the wheel to inspect it, and spun the axle with my fingers. It felt very dry, and not smooth at all - would catch a little when I tried to spin it. However, it had not developed any play that I could detect.

There is no point in trying to re-grease the bearings. Due to the shield, they have to be removed for greasing. Removal requires you to drive them out by their inner races, and this operation is very likely to damage them.

So, once they are out, it only makes sense to replace them, considering how cheap and available the parts are.

If the parts were not available, I would have flushed them clean with solvent, repacked them with some fancy Moly EP grease, and prayed.

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