Where's my balls?

Wingboy

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I knew going into this URAL things that there would be moments.i noticed a little ticking noise a few days ago. I found some wear on the rubber donut in the driveshaft, so i replaced it. Rear wheel and driveshaft have to come out. Getting ready to reassemble and found this. Bearing to the sidecar driveshaft is missing some balls. I'm not worried about getting a new bearing and seal. But where did the balls go?
PXL_20260409_222442524.jpg
 
gone reduced to atoms.jpg
 
Also, if that cage is missing, the balls can all go to one side of the bearing and allow the central race to shift to the other side by enough to allow balls to escape. That (in the putting-together direction, as opposed to the coming-apart direction, of course) is how they assemble the balls into the bearing to begin with. The cage goes in around the balls afterward.
 
Also, if that cage is missing, the balls can all go to one side of the bearing and allow the central race to shift to the other side by enough to allow balls to escape. That (in the putting-together direction, as opposed to the coming-apart direction, of course) is how they assemble the balls into the bearing to begin with. The cage goes in around the balls afterward.
Ok. I don't think there are any missing balls. Just broken plastic cage.
 
I don't want this to sound like I'm being hard on it, as you say you knew there would be moments. I am curious though, many kilometres did that bearing accumulate before exploding?
 
I'm assuming drifting it (and maybe even hard turns) may side load that bearing too.
Probably. I think i ride harder than most Uralites. The plastic could have been defective also. There doesn't appear to be any other damage.
 
Replace that with quality brand 3204 2RS or 5204 2RS (either will work).

The plastic cage failed because the bearing got contaminated. 2RS bearings are sealed, you can’t easily grease them - you don’t need to.

Thst unsealed FAG bearing is cheap and dirty, SKF 3204-A-2RS1-TN9 would be my choice. Better internal geometry for side loads (A), heavy grease retaining seals (2RS1) so less maintenance (no periodic lubrication) and less chance of contamination, and reinforced cage (TN9). You can smear a little grease as a trap on the outside of the bearings for a little extra protection from contamination.

You don’t want a steel caged version for a motorcycle wheel bearing. They run hotter, noisier, and not as smooth at speed. Poly cage bearings fail when contaminated… so does steel.
 
I agree. Looky here SKF 3204 A-2RS1TN9/MT33 Double Row Ball Bearing, Converging Angle Design, 32° Contact Angle, ABEC 1 Precision, Double Sealed, Plastic Cage, Normal Clearance, 20mm Bore, 47mm OD, 13/16" Width, 2700.0 pounds Static Load Capacity, 4500.00 pounds Dynamic Load Capacity : Amazon.ca: Industrial & Scientific

That's a lot more expensive than what was shown for the OE replacement above, but personally, I would do it. 15 000 km for a wheel bearing (or driveshaft bearing) is a premature failure, and barring severe overloading or improper installation, contamination is usually what does them in.

Motorcycle wheel bearings are often sealed on one side, or unsealed and reliant upon a separate seal. I always replace them with the sealed variety when time comes to replace them. You'll never notice the 0.001 N.m of extra rotational drag from the extra seal.
 
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