yannisg

Cannondale Synapse, FSA crank with BB30 BB.

Because of a clicking sound I decided to replace the brgs after doing simpler things such as removing crank and chainrings, cleaning everything and torquing to spec.

I pressed in new brgs that were specific to BB30 and not commercial.
When pressing crank from DS into the brgs it didn't go all the way in. Even though I tapped it still need to go in about 8mm to be seated properly. I didn't want to tap it harder thinking that the impact might affect the brg.
I ended up putting the NDS crank on and pulling it into position.
After torquing the NDS to spec the crank turned smoothly, but would not spin freely as before with the old brgs. If I would give it a spin it would turn 1 1/2 rev.
The brgs were new, but had been stored for some time so maybe the grease had stiffened.
As for the axle not seating with a slight tap could be attributed to brg inner race tolenrence.
If I had suspected this I should have frozen the crank before installation.

If the gap had been larger I would not have been able to install the NDS crank and pull the axle into the seated position.
However, the "pulling into position" stresses the brg since you are pulling on the inner race with supporting it.


Any views on this situation appreciated.

maddog34

give each side of the crank a firm, but not maniacal, whap with a plastic dead blow hammer or wood block/hammer... this will relieve and equalize the side preloading a bit.. re-check for smoother spinning.

a bit of tape on the cranks will help prevent finish damage.

those bearings aren't as delicate as some believe.... their seals and ball retainer cages are delicate... the balls and races are hardened high strength steel.

yannisg

I'll take the bike for a couple of rides and see if the cranks spin better.
When you place a force on a brg race with supporting it you can damage the retainer and cage.

yannisg

I'll take the bike for a couple of rides and see if the cranks spin better.
When you place a force on a brg race with supporting it you can damage the retainer and cage.

Pls correct "brg race without supporting it" instead of "brg race with supporting it"

maddog34

so, by your "logic".. you should never ride your bike since pedaling loads the crank bearings....
and if you ever crash the bike, the bearings that you can't use must be replaced...

and the "retainer" and "cage" are the same thing...unless we're now discussing some type of bearing other than a balls and races style... Some Balls/Races bearings do incorporate a retaining clip and groove on the outer race......

yannisg

Maybe I wasn't clear.
What I meant is that the cranks would spin freely with the old brgs, but with the new ones the crank would not spin as freely, and this I attributed to the new brgs which were stored for a long time before being used, and maybe the grease had stiffened.
However, after the first ride today the cranks spin already more freely.

I agree that cage and retainer are the same, but my point was when pressing on a brg race either inner or outer it should always be supported otherwise you risk damaging the brg.