Bicycle Mechanics - Fixed cup...to remove or not to remove, that is the question.

Hey all,

I have officially begun my mtn. bike build and have run into a snag.
I am converting the old square tapered bottom bracket with one of the splined variety. (haven`t decided what yet...) I removed the bb with no problem but I am unsure as to whether or not I have to remove my fixed cup. It`s in there pretty solid, and I guess my question is; is it necessary to replace the fixed cup? It seems to be in perfect shape so I figure it`s good to go...unless there`s something I`m missing.

Thanks in advance for any help you pros can give me. :)

I think it depends on whether or not your want the splined spindle or keep the tapered BB.
You'll need new cranks with the splined.

I'm not sure splined spindles (for cupped BB's) are that widely available at least I've never seen one.
You might want to take off that cup though, clean out the whole thing nice-nice.
While you're at it.. put in a sealed bottom bracket. They make life so much... better.
Make sure the BB length is correct.

If however you do have a really nice old school BB, I'd keep the old stuff and replace the bearings.
Check for any BB cup bearing race wear.

Good luck.

Your new BB will (likely) be a cartridge unit; in which case you'll need to remove the fixed cup.

Your new BB will (likely) be a cartridge unit; in which case you'll need to remove the fixed cup.

Doh!

I didn`t even think of that...and that`s why I`m still a newbie.:)

Thanks for the responses guys, I guess I`ll be taking the fixed cup out after all.

Remember, the fixed cup (assuming an English bottom bracket) is left-hand threaded so it comes out by turning it clockwise.

Remember, the fixed cup (assuming an English bottom bracket) is left-hand threaded so it comes out by turning it clockwise.

And it is a bugger to get off if it was installed correctly. They imported gorillas to get them on in the old days. That's why there aren't any gorillas in the wild:D