Anyone know the replacement bearing in Hollowtech ll?
- Thread starter koro
- Start date
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2Loose
Guru
- Location
- Loughborough, Leicestershire.
When you swap out your old one, why don't you dismantle it...you'll then be able to measure for yourself...or am I missing something?
They might be simple to replace, but the rubber seals ARE delicate, so be gentle.
gbb
Squire
- Location
- Peterborough
IIRC, FSA and Hollowtechs both use 6805 bearings, but it may depend on the crankset.
Worth remembering if like FSA Omega BBs, there's a tophat washer that protects the bearing and also acts as a sleeve between the axle and bearing...you'd almost certainly need to replace that as well if its done any reasonable mileage. The plastic wears out between the axle and bearing.
If it's 6805, the numbers are..
6805-2RS, which is a double sealed standard bearing.
6805-1RS, single sealed ...the other sides open...as with FSA Omega. I dont know whether its worth even buying a -1RS, you just slip the second seal out with a blade or screwdriver.
61805-2RS are deep groove bearings, same dimensions, just machined differently internally. They're slightly more expensive but i dont know whether it makes any difference on a crank.
Cheap 6805 bearings are uncaged (as with FSA Omega). The balls are free running in the cartridge. The seals won't be as good either, thats why they fail so quickly.
Better quality manufacturers like SKF, INA etc etc have the balls held within a cage that runs in the cartridge.
Basically, you buy cheap, they'll do the job, but not for so long.
You can get low friction seals on SKF bearings. I think they're -2RSL, there's a huge difference in how they spin.
Worth remembering if like FSA Omega BBs, there's a tophat washer that protects the bearing and also acts as a sleeve between the axle and bearing...you'd almost certainly need to replace that as well if its done any reasonable mileage. The plastic wears out between the axle and bearing.
If it's 6805, the numbers are..
6805-2RS, which is a double sealed standard bearing.
6805-1RS, single sealed ...the other sides open...as with FSA Omega. I dont know whether its worth even buying a -1RS, you just slip the second seal out with a blade or screwdriver.
61805-2RS are deep groove bearings, same dimensions, just machined differently internally. They're slightly more expensive but i dont know whether it makes any difference on a crank.
Cheap 6805 bearings are uncaged (as with FSA Omega). The balls are free running in the cartridge. The seals won't be as good either, thats why they fail so quickly.
Better quality manufacturers like SKF, INA etc etc have the balls held within a cage that runs in the cartridge.
Basically, you buy cheap, they'll do the job, but not for so long.
You can get low friction seals on SKF bearings. I think they're -2RSL, there's a huge difference in how they spin.
gbb
Squire
- Location
- Peterborough
If you do dismantle the old BB, the bearing number is usually written on the seal of the bearing.
gbb
Squire
- Location
- Peterborough
Quick recap..the bearings in my FSA were 6804 not 6805. That said i read 6805 were fitted to Hollowtech IIs.
Clear as mud then
Clear as mud then
accountantpete
OAP
keep the original bearings, wash out the grease with wd40, dry and then oil.
They will be as fast as the most expensive ceramic bearings you can buy.
They will be as fast as the most expensive ceramic bearings you can buy.
