Cranks not spinning with new external BB cups.

moyesie

I'm currently running an FSA SL-K chainset with external bottom bracket cups.

Last year I had issues with the BB as despite feeling like it was running freely it creaked terribly under pressure, they were eventually replaced with another FSA BB but the creaking soon returned, even although the BB has done 'only' approx. 1000 dry miles.

As part of my spring rebuild I decided to replace the BB with a Shimano 5800 Ultegra unit, nice and cheap with proven reliability.

Having installed the BB (to the correct torque) I find that the cranks really struggle to spin, its clear they are clamped too tight.

The only thing I can think of is the although they listed as being compatible with FSA there is a very small difference in the overall width, thus causing the crank to clamp too tight?

I'm I destined to only use FSA BBs or have I missed something obvious?

I've tried both 5700 and 5800 BBs with the same result and when I put the FSA BB on my Ultra equipped winter bike it works fine.

Help!

arlowood

I'm not sure you should be too worried.

I've fitted quite a few Hollowtech 2 cranksets to a variety of HT2 BB's including recently the latest 105 5800 into an Ultegra BB. In my experience the cranks never spin freely when fitted new. Even with the pre-load nut removed entirely there is still enough resistance to prevent the cranks spinning more the about 1 revolution without the chain fitted .

I think it is just down to the packing of the external bearings and after a bit of mileage they will ease off.

Can't speak for FSA cranksets but I presume the same situation would apply

moyesie

Thanks for the reply

This is 100% not as it should be, I know what you mean about some BBs having resistance when initial fitted. The level of resistance in this case means its actually difficult to turn the cranks even with force.

thebadgerboy1982

sounds like the preload isn't set right. with shimano cranks the preload should only be hand tight, maybe 2nm's

trailflow

This link says its not compatible.

http://weightweenies.starbike.com/forum ... 3&t=123195

Monty Dog

SLK uses a narrower BB bearing - you'll be overloading the bearings on the HT2 BB and they will feel rough / wear-out quicker.

moyesie

Arse!

Had a chat with the LBS, they suggest trying it without the FSA 'wavy washer' on the Shimano BB, certainly having tried it that way originally (on work stand) it would that that may be the solution.