I came across a vintage Sugino Mighty Compe crankset in near perfect condition, probably from the late 70's. Crankarm says 171 and 46.11, and the rings are 54 and 48. I don't know much about this set but from what little research I've done it seems they were comparable to Campy Record at their time. I'm building a bike for a friend of mine and was wondering if I should toss these on and what gear ratio to run for him? What rear cog size, etc. running the 48 up front.

Any advice would be greatly appreciated.

Thanks,

Steve

EDIT: Also, they're going on an italian frame, what BB would I need for them to be compatible?

why are you going for them?
depending on the price, it may be more advantageous to go with a track crank over a road double. mainly for chainline compatibility, but additionally the .6 cm shorter crank buys you a few degrees of pedal-strike-free bank into turns which could be pretty valuable depending on the bb height of the frame you're building up.*

that said, the optimal chain ratio depends greatly on 1) whether he'll be doing stop-and-go riding (in a city for instance) versus long uninterrupted rides, 2) whether you live in a flat or hilly area, and 3) what kind of rider he is (high cadence vs masher).


*pedal strike isn't nearly as important an issue if you're using a freewheel, btw.

if you're doing that, you should get a double cog. that would be sweet.

I already have them. I found them on a junkyard bike in mint condition, therefore they are FREEEEEEEE.

He lives in SF, so it's pretty hilly. He rides a regular 10 speed but usually only stays in his lowest gear.

I only plan on running the 48...that would be the best idea right? 54 would be too big, yeah?

okay, with that information, go with a double cog. that way he has two options.

i agree that the inner 48 makes more sense.
aside from having a better set of realistic cog tooth options, you're less likely to run into chainline issues by using the inner, so you're off to a good start.

as for the gearing, i'd keep it small but i don't live in san fran so i can't say what cog would work best. i run 47 x 16 and do ok on steeper hills, but i don't deal with them on a daily basis by any means. perhaps an 18 would be a good place to start? How strong of a rider is he?

He's a pretty strong rider, just hasn't given into the hipster trend....you could almost call him an anti-hipster, hah.

Do many companies even make 18T, have only found a few on eBay? Could I just run 48x16 or so?

48 x 18 is pretty close to 70 gear inches which is typically what most fixed riders run. 48x 16 is almost 80, definitely not SF friendly. If he's just starting out i'd go ahead and get a 19t cog. Soma, Surly, Ben's Cycle all make one that big.

Awesome, I appreciate the help.

I got a nice set of the same cranks from 73, also 171 mm, with a 54-45 combo. Planning on going with 45 16 for next summer.