chainline question

Hi guys. So my rear hub is an orgini8/formula which I believe is 42mm chainline correct? I got a set of sugino messanger RD2s and the sugino site says a 103mm bottom bracket. I bought a 103mm bottom bracket, installed everything. The chainline is way off, well seems like it anyway. I had a read on the internet and turns out RD2s with 103mm bottom bracket actually gives a 45mm chain line (so im guessing these are incompatible if I want a perfect chainline) For now I am running a 110mm bottom bracket and the chain ring on the inside of the spider which gives a decent chainline. Any body know of any solution instead of running the chain ring on the inside?

Also does this site have a for sale section? and If so how do I get access??


If your chainline’s ok as is, just leave it.

And you have trading access btw.

Did you get the matching Sugino bb?

If not, check that you’ve got your spline matched to your crank, i.e. ISO or JIS. Pretty sure you want JIS for RD2 but NJS parts are ISO.
Square Taper Bottom Bracket Interchangeability

RD2’s are JIS taper. JIS cranks on an ISO will give you a chainline closer to the frame than you desire. Likewise, ISO cranks on a JIS taper will give you a chainline that sits too far out. So I don’t think this is the issue.

If you’ve got clearance between the cranks and the outside edge of the bb cup, you could just get a shorter bb axle.

In my experience you’re never going to get a ‘perfect’ chainline unless you use parts specifically designed to mate ie sugino 75bb with sugino 75 cranks.
Further, in my experience it doesn’t even matter if you have a ‘perfect’ chainline, you just want it to be pretty close.

Agree with this

^— This…

Been here with Sugino RD cranks. As people with point out, RD = Road Double. So they are not track cranks.
I have 3 sets of these and one set give me a 42mm chainline on a Sugino 103mm BB. The other two sets give a 45mm chainline
as you describe.
So if it’s working with the 110mm BB with the chainring on the inside of the spider then leave it as suggested.
A reasonably cheap alternative is a set of Token track cranks that will give you a 42mm chainline on a 103mm BB.

Cheers for all the fast replies guys! Yea both the bottom bracket and and cranks are JIS, I just didn’t know RD2s had a 45mm chainline. Running the chainring on the inside of the spider pretty much fixes it so i guess I’ll just leave it how it is.

get a 107mm BB? I know that you can get a Shimano UN-54 in this length, and pair that with a problemsolvers Up-Cup if you get annoyed with the shimano plasic cup that comes standard.

yea technically a 107mm bottom bracket with the chainring on the inside would give the best possible chainline. will give it a try when I got some spare cash. Just wasted 40 bucks on a 103mm bottom bracket :frowning: haha

sell 103…buy 107.