More on BB Bearings

[Titanium Rocket]

I don?t want to add this onto the mega-thread about BB?s, but can anyone help with these questions:<?: prefix = o ns = "urn:schemas-microsoft-com:office:office" />

 

1.       What are the exact codes for the bearings in an XTR Shimano Hollowtech II BB? (Seems they are different to XT and LX).

2.       Are Endura bearings really worth the price? Do they give you double the life of FAG or SKF?

3.       Just opened an XTR BB this weekend. One side of the bearing is sealed, the other is open. Is this to apply more / new grease, yet it says clearly ?do not disassemble?.? So why not have both sides sealed? Why does the open side face outwards from the cup, most exposed to all the gunk and crap?

[techguy]

I stand to be corrected but the Endura brand is just that-a brand I don't think they are any better than FAG or SKF (perhaps someone in the industry may spread some light...)

 

The side that is open has a couple of seals that you must have removed first the sealed side is on the inside to keep water and gunk that sits in the frame out. the "open" side has the plastic cap and the rubber seal that runs against it... 

[touringza]

Anyone know what the codes for Shimano external BB cups (not the bearings) signifies?

Mountain GA, DH, FC, FH, FJ, FK, etc.

[Johan Bornman]

With the code, do you mean the actual cartridge bearing inside the BB cup's code?

 

If so, then the answer is no code. Although Shimano puts 6805 RS/2 on the bearing, it is not a standard 6805, but 1m narrower than the industry standard 6805. I suspect they simply used stock standard 6805 seals on their proproprietary bearings since the seal size is the same, it is just the bearing size that differs.

 

Therefore you cannot replace these with standard SKF cartridge bearings. I say this with a few exceptions to cup size becasue there are two different cup designs in the Shimano stable.

 

 

Further, the Enduro bearing for replacing the ball bearings inside BB adapters (cups) is a special size that's only available from Enduro. It is designed to do away with the plastic press-fit sleeve inside the BB cup and allows the crank axle to fit directly into the bearing.

 

Are they worth it? Hell yes. R180 for a bearing kit (fitted if you buy it from someone I know) versus R800 odd for top-end BB cups.

[touringza]

No, not the bearings but the cups. Two examples: GK and GA, have seen many others; DH, FC, FH, FJ, FK, etc.

Note on these the different wall thickness and the different dust seal/top hat design.

Edited October 31, 2010 by touringza