I need to replace the bb30a bottom bracket bearing on my super six evo. Never done it before so need some advise really and any tips people can give me.
From looking at the bearing there seems to be a lip behind the bearing on the inside of the frame, I assume this is the cup that it sits in, when I’m tapping out the bearing is it possible to leave the cup in situ, or is more than likely going to come out as well? How do you press the cup back in if it does come out? Does it just get pushed back in with the bearing ?
Also do I use carbon paste when putting it all back together?
Apologies for all the nooby questions.
I did this several times on a 2012 EVO and a CAAD10. I recall there is a circlip but not a cup. Whatever it is, don’t try to tap that out. Avoid hitting the “lip”. Doing so may damage the inner surface of the shell or worse. Tap on the inner ring of the bearing to remove and do it as evenly as possible. I would use a piece of wood or ABS pipe and try to support the outer edges of the BB shell against a firm wooden surface. Any significant misalignment of the bearing in the shell can alter the fit. Do you have a bearing press for installation? You will need that or something to serve as the equivalent. Do not tap to install b/c the strikes will damage the bearings and there is the misalignment/fit problem to navigate again. No carbon paste. It is just a simple friction fit. Make sure the shell-to-bearing surfaces are clean. Use grease, anti-seize, or even loctite. You’ll get creak if the fit between the shell and the outer bearing surface is not good (enough); or, if the two sides are not sufficiently concentric.
Thanks. I have press to reinstall the bearing but just wasn’t sure about getting the existing ones out.
Been out to look at this BB again I don’t see how you can tap out the bearing as there is hardly any gap between the lip at the back and the bearing. I can’t get anything to go just behind the bearing.
That looks different from what I had. It must be a more recent model. Even supposing it is a cup, and you got the whole thing out, you would still need to separate it from the bearing and that doesn’t look straightforward. From the backside, there appears to be enough exposed material to work on. There has to be some or the axle would not clear. You would need to use something like an tube or dowel with a clean, square edge. A tube slightly smaller than the axle, enough so that you could tilt it inside the hole. Or, you can hacksaw 4 even slots at 90deg into a metal tube nearly the diameter of the axle and splay out the ends a bit. I’ve also seen other tools for this which leads to another idea, if you have a hacksaw and files. Cut a flat metal piece abt 1 cm wide and the diameter of the lip. File long edges round so that it just fits inside the lip. Fit this into place and tap on that.