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BB replacement Q: can replace oldskool with new?(4 posts)

BB replacement Q: can replace oldskool with new?Amanda Hugankis
Nov 28, 2001 1:50 PM

I got a 1980s trek frame with the standard old BB. Can I replace this with a tapered spindle, sealed cartridge, shimano type BB? Is the frame threading the same as it is today? Will the old 105 cranks fit?

Mucha grasa on your bearings,

Definite Maybegrzy
Nov 28, 2001 2:04 PM
Well "new school" would mean a splined crank/BB interface in most people's minds, but we know what you meant.

You should be able to get a BB to fit - question is what's the shell width, threading, and spindle length. Easy to figure out - sort of. Shell width is most likely 68 mm and threading is most likely English, but you should verify. The spindle length is not only a fuction of the frame but also the crank it will be mated with - so you need to know this. the taper spec hasn't cahnged much, but your cranks cold be failry worn which would move them inward on the spindle - maybe. A decent LBS wrench should be able to guide you through this and make it work. However there are some cases when things just won't work or you can't find the right part anywhere. then you can pony up to the bar and order exactly the right BB from Phil Wood & Co. (i.e. Swiss threads in an old Motobecane).

Now all this assumes that you're matching this with the older style square taper cranks - if you go for something new then you're looking at the SPLINE design aka "Octalink".

Step back and ask yourself what you're trying to do and if it's really worth it - sometimes the answer is yes, but not always.
re: strangely aroused yet disturbed by your handle...Akirasho
Nov 28, 2001 2:42 PM
... ditto what grzy said...

We abide.

Remain In Light.
shouldn't be a problemempirebikes
Nov 28, 2001 10:12 PM
I am 99% positive that you need a 68mm english Bottom bracket. As far as the spindle length goes you can pull the crank arms off and measure it, iF you have not ever done this before than go to a local bike shop. Unless you have sentimental value in the bike it probably isn't worth upgrading to a spline drive BB and crank.