BB spindle length.

Im wanting to get new cranks, sugino’s, and apparently a 103mm spindle is meant to be used (According to However, I’m currently using a 107mm spindle with eighthinch branded cranks and have a straight chainline. Both are JIS spindles.
Does this mean the Sugino cranks DO need a 103mm because they fit on the spindle slightly less, or could it just be dependent on the rear sprocket?

you need to give more information.

Sugino cranks use both JIS and ISO tapers

for example Sugino 75s and all its derivatives use a 4 taper ISO with a chain line of 42mm with an ISO bottom bracket of 109mm.

I think the rest use JIS but I am not sure

To answer your question people will need to know the chain line you are running now in terms of dimension. Then working with your 107 mm spindle and taper somewhere on "skynet " will be the chain line you will get with your sugino whichever ones they may be.

As always i would start with sheldon brown.

Hope this helps

full face

I guess a better question to ask would be, if two different cranks are both JIS, ie. Sugino XD and RD, would they have the same chain line if used on the same spindle? Or could one still attach closer to the frame than the other?
Wasn’t able to find this particular answer on Sheldon.


Different cranks can and often do require different spindle lengths to get the same chainline. That’s really got nothing to do with whether they are JIS or ISO tapers.

Cheers, thanks for the help guys/girls

The question is really where the chain ring sits in relation to the taper. Different cranks will produce different chain lines even on exactly the same spindle length and taper.

Best approach is to work out what your current chain line is, measuring from the centre of the frame to the centre of the chain, then work out a corresponding crank and spindle combo.

if it’s an RD2 crank, the matching bb is a 103mm…