Bottom Bracket spindle length confusion...
 

Hello all,

I am out of my league when it comes to understanding all the measurements on bottom brackets. Here is what I am trying to do, I would like to replace the BB on an old vitus frame I picked up, before you ask it is English thread. I want to set this bike up with a 9 speed campy record group. From what I gather, the record BB is a 68 x 102, however the original BB is 68 x 120. It had an old stronglite crank on it.

Seems like longer spindles these days are intended for triple cranks, the orginal stronglite crank on this bike is just a standard 2 ring. Is the spindle length a factor of frame line up, or derailer reach? Or is it simply a factor of the crank you are using? I.E. I am using a campy 9 speed crank so therefore use the corresponding BB? If I use the old stronglite crank then it requires a 120mm spindle...etc. it needs the stronglite BB to install correctly.

I should add that the reason I wish to use a campy BB is mainly the weight. The orginal stronglite BB is quite heavy, but it is in good serviceable condition... The crank is kind of beat up though. I am also guessing that I could not fit the campy crank on the original 120mm spindle..

This old frame is amazingly light and I was hoping to do it some justice with some campy parts..

Any reply is appreciated..

J

Yes, proper spindle length is determined by the crank. If you want to use the Campy crank, use the matching Campy bottom bracket in Campy's recommended width. What your old Stronglite crank required is not a factor with the Campy crank.

Older cranks used longer, asymmetrical spindles; that's what accounts for the length difference you note. So, you'll want to use the Campy spindle for your Campy crank.

Thank you very. Ugh for the information, appreciate it!

j

Got it! Thank you very much for the info!

j

The recent Campagnolo Cranksets , like maybe yours, certainly mine. the right crank arms are different, the triple and the double.
so they share the same spindle I have a 'Race Triple' it comes into meet a 111 symetrical BB cartridge type ..

the older type the arms were the same , then the spindle, asymmetric , was where the different chain lines were sorted out.

The spindle width can make a big difference if only being off by a few mm especially for triple rings.