Hi,

I decided to replace my Power Pro BB-9915 with a new bottom bracket and for some reason bought SRX from Race Face.

There is an odd 'feature' in this SRX: For some reason the non-drive cup 'brakes' the axle. That is, the axle doesn't rotate easily when I hold the non-drive cup in place with hand. The old BB rotates much smoother than SRX.

And, when installed the SRX to my CC bike, the axle almost stops to rotate when I tighten the left cup.

Do you have ideas, what could be the reason for this 'feature'? Should I use grease more generously or what is the problem here? I hope someone could help me before I go to shop to buy a new BB.

Some pics below:

https://img338.imageshack.us/my.php?i...uvia002sy9.jpg

https://img158.imageshack.us/my.php?i...uvia003gw5.jpg

https://img67.imageshack.us/my.php?im...uvia004ww2.jpg

Some isis bbs have bearings that are not attached to the shell. The cups fit directly onto the bearings. Without the cups when you hold the shell and rotate the axle the whole bearing can rotate with the axle. When you fit the cup it spans the bearing and shell holding both together. Now when you rotate the axle the outer bearing race is held with the shell and doesn't rotate with the axle. The extra friction is probably from the bearing seals. If you grab the bearing while rotating the spindle you should get the same amount of friction as with the cup attached.

Thanks for a quick reply. My SRX is exactly the model you describe; bearings rotate with the axle. And yes, the friction seems to be caused by bearing seals. But something goes wrong when the BB is mounted: Friction increases so much that the axle rotates with difficulty.

Hi,

Could you guys still comment this one: I got a hint that the reason for too much friction could be uneven rims of the cycle's muffle. And this would cause twisting of the bottom bracket so that bearings, which are not attached to the shell, get 'jammed' (bearings don't run smoothly when BB is installed).

?? got me on that one ?? if you mean uneven faces on your bottom bracket shell, that's a distinct possibility. doubt you want to spring for the tool, but your LBS can face it for you.

Thanks "vpiuva". It's just that I'm not native English speaking and some technical terms are new to me. But yes, I wanted to say uneven faces of the bottom bracket. I just contacted LBS (new term that too) and they said 'facing' will cost 20 euros.