Servicing 7900 hubs - ball retainers

[bprb]

Some of the ball bearings in Dura-Ace 7900 hubs are enclosed in plastic retainers:
http://techdocs.shimano.com/media/techd ... 728255.pdf

Can anyone advise on the best option if I want to put in new balls when servicing the hubs?
e.g.
(i) Buy new retainers + balls (are these even available?); or
(ii) Remove the old balls from the retainers and push new balls into the old retainers (I haven't tried it to see how feasible this would be); or
(iii) Ditch the retainers and just put in loose balls?

Many thanks if someone has experience they can share.

[jcjordan]

The bearing in Shimano Hubs are of a very high quality and unless there is ovious signs of pitting I would not bother to replace them. Just give them a good clean, along with the race, pack in some good grease and put it back together.



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[bprb]

Thanks James, that's what I did the last (and so far only) time I serviced them — wipe out the old grease and put in fresh stuff. I guess I was just swayed by articles I've read previously that suggested putting in fresh balls when servicing cup and cone hubs. But maybe if it aint broke, don't fix it.

As an aside, I was impressed by the seals on the 7900 hubs. Despite quite a bit of riding in the wet, the grease was quite fresh and seemingly uncontaminated, compared to what I was expecting from my previous experience with 6600 and 6700 hubs. The 7900s were also a pleasure to reassemble — I enjoyed not having to fiddle with cone spanners to leave just the right amount of looseness in the lock nuts.

[jcjordan]

Thanks James, that's what I did the last (and so far only) time I serviced them — wipe out the old grease and put in fresh stuff. I guess I was just swayed by articles I've read previously that suggested putting in fresh balls when servicing cup and cone hubs. But maybe if it aint broke, don't fix it.

As an aside, I was impressed by the seals on the 7900 hubs. Despite quite a bit of riding in the wet, the grease was quite fresh and seemingly uncontaminated, compared to what I was expecting from my previous experience with 6600 and 6700 hubs. The 7900s were also a pleasure to reassemble — I enjoyed not having to fiddle with cone spanners to leave just the right amount of looseness in the lock nuts.

the new step guide on the cones for the 7900 are a dream for the mechanic and make home servicing so much easier.

That being said i think that the old 6600 and 7800 are also really good. Have a set of 6600 that are on my everyday wheels and all I do is service the hubs with new grease every year. I have had these wheels since 2055 and I replace the bearing for the first time this year.

[Reman]

I wonder why Shimano decided on bearing frames, when all their other hubs use free bearings...?

[jcjordan]

I wonder why Shimano decided on bearing frames, when all their other hubs use free bearings...?

It's meant to make the bearing sit better during hard corners but requires a higher tolerance in matching the race to the bearing.

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[Reman]

On my 105 hubs with free bearings I can definitely hear a different bearing sound when cornering.