Briareos

Looks like I might have 2 DA 7400 sets soon and so one will go on the singlespeed. But my only problem is the spindle length is 112mm for the crankset normally used for road, how do I calculate what size spindle I need for a 120mm frameset? Or should I just mount the chainring on the inside with a chainguard on the outside (not a bad idea) and a seatpost inner chainring ring retainer (even better)?

fly:yes/land:no

i am not sure how you decided to pick the road bike racing forum, but perhaps this thread should be moved to the general road forum, or more appropriately, the ss/fg forum. (i think you can request a mod to do this, as well as just doing a search of the ss/fg forum to find what you are looking for)

i have at most a partial knowledge of chainline issues. i think it is very typical for ss conversions to move the chainring that they are going to use to the inner position on the spider. i believe they make chainring bolts for this called "shortys," but i am not sure.you can also play around with the axle spacing to try to get the cog in the right position after you have moved the chainring in.

also, google search sheldon brown, and you will be enlightened much more than from my post.

CastIron

7400 cranks were built for bikes with 126mm rear spacing. Given the small amount, I'd install 'em and dope out the ~1/4" difference from there.

justinb

Read your bible.