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just swapping the bearings on my rear hub. They're a EZO 6902 RU so low contact / low drag seals that apparently maintain excellent sealing properties.
The reality for me is that my bearings failed after 45 miles. Circumstances meant that the bike sat unused for 2 months but taking apart the hub and removing the green bearing seals i found the bearing race is completely rusted and corroded and race is siezed. They look like they've never seen grease in their life.
The company has been fantastic, sent out replacement bearings and a hub tool but TBH....45miles!!!! WTF??!!! The replacement bearings this time dont appear to be RU, instead angular contact with a black and red seal.
Is that to be expected from the RU type bearing? Would an angular contact bearing fair better or should I better to go LLU Max full compliment? Riding round me is proper gritty slop so no chance of keeping dry. And there's no way I want to go rebuilding every 50 miles. Especially as the hubs need a specific tool and two have broken in the process of removing the ratchet ring.
Half thinking new wheels would be easier if this is what i can expect!!
I'd go better sealed if you can, 6902 are common, and I usually go the LLU or 2RS route. You'll never notice the tiny increase in 'friction'. Like all this ceramic bearing rubbish too.
Don't get max/full complement bearings, they are generally designed for high loads and/or reciprocating motions.
Just get better sealed bearings, or carefully pop the seals off and fill them to the brim with grease, or do both.
Lot of manufacturers just spec a basic bearing with a low fill as it's cheaper.
Gotta grease them.
@mert - interesting. Out of curiosity is there a particular reason not to go max bearings in hubs? I’d never thought about it other than more grease might have a little more friction but be almost unnoticeable when riding. Or is there something in the race meaning they wont last as long / not suitable.
The ones i took out are EZO so was expecting better but it seems the problem one had zero grease. Never seen anything like it. Even after 24 hrs soaking in gt85 the race is still seized. I’m thinking it was faulty out of the factory.
Sounds more likely that the inadequate seals let water in which corroded the races between uses.
interesting. Out of curiosity is there a particular reason not to go max bearings in hubs? I’d never thought about it other than more grease might have a little more friction but be almost unnoticeable when riding. Or is there something in the race meaning they wont last as long / not suitable.
The balls run against themselves, rather than a "static" grease filled cage/holder. So they'll wear faster and produce more drag.
Full complement also tend to have less grease in them (if you fill the race!).
I thought the issue with full complement was the groove that has to be ground into the races to get all the balls in - inevitably this causes wear.
Yeah. That's another thing that causes issues.