5

So I bought a Chris King PF30 bottom bracket and pressed it in using a bearing press along with the bushings that came with the Park Tool bbt-30.3. Using the bearing press I pushed both cups in simultaneously. Ever thing seems to fit in ok and is sitting what appears to be straight, but the cup on the drive side feels like it has some stiff spots in it's rotation compared to the other side. I'm moving the rings with my fingers, I haven't installed the cranks yet.

Could this be an effect of the seals or bearings? Is that side not seated in straight? Should I knock out the drive side and try press it in again a second time?

I'm not sure what I'm looking for to know that I did the job right, before continuing on assembling the rest of the drivetrain.

Improve this question
3
  • I installed a press-fit bb during the summer but experienced none of these issues. I did what you did, stopped pushing when everything was flush. Felt great. For 10 minutes work it might be worth putting the cranks on and seeing what it feels like to ride. If not right, probably worth refitting and see whether that makes any difference.
    – PeteH
    Nov 12 '13 at 19:37
  • Anecdotically, I recently installed a threaded BB. There were stiff spots when turning with fingers. Currently I have ridden the bike for 2 weeks and there is no problem whatsoever. There is no apparent resistance felt through the cranks. Must have been the seal.
    – Vorac
    Dec 2 '13 at 15:07
  • Curious. Did you use loctite?
    – ewwhite
    Aug 30 '14 at 19:00
3

It looks like that Park tool is specifically designed for use on PF30 BB's (+1 for using the right tool). Just curious though, how do the bushings line up with the BB? What surface do they push against? If they push against the inner race, you may well have damaged the bearing. If they push against the outer race or the bearing cup you should be fine. The bearing (i.e. internal race) isn't designed for purely lateral loading.

enter image description here

Are you certain that it didn't have any stiff spots before installation? You can try popping it out and free spinning it in your hand. If its still stiff outside the frame its certainly damaged.

Even if you pressed the bearing cup in completely bass-akwards it shouldn't bind the bearing. The outer race and cup are thick enough that it would take serious damage/force to deform the outer shape of the bearing to cause any noticeable friction.

To address one of the comments: If this is new it shouldn't have any stiff spots. Even the cheapest bearing should spin smoothly out of the box. Putting the crank on will change the inertia of the system and only make it harder to detect these spots.

Improve this answer

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.