Ive been trolling this site for years and have read alot of good tips and advice but ive run into a question where I needed to post.
I have a 2010 gary fisher rail super 9speed and I need to replace the bottom bracket. The part is
The Vero double cranksets use a JIS (Japanese Industrial Standard) square taper spindle bb and the length is @ 103mm.
BB7420ST Cartridge BB
I guess I can order the part from full speed ahead but since Im buying a new one anyway, I wanted to upgrade to something better.
my question is, what specs has to be same as the one listed above. I'm guessing it has it be a 69x103mm in size and a square taper.
Is that all I need to match??? are bbs and cranksets tied together or as long as its square taper im good?
You can get by with a slightly different spindle length. It can be a couple of mm longer,
or sometimes you can even get by with shorter, depending on clearances.
ISO Arms on JIS spindles work fine all the time, but it moves your arm and rings
outboard a little bit, thus the chain line moves outboard.
You can't always mount a JIS tapered crank arm on an ISO spindle, but sometimes
you can and it works fine. Every variation from your original usually moves your
chain line a little, sometimes a lot, sometimes too much.