Is Sugino Triple Ring Crank Compatable With my project
 

Hi we are building a drop bar conversion on a Rock Hopper that currently has a shimano 8 speed free wheel. We want to upgrade to a Triple ring in front. An older peugot was given to us that has a Sugino triple crank. My question is will I be able to use this crank? I will likely have to replace the BB? Thanks in advance to anyone who can hel. We are completely replacing the drive train and currently are scheduled to get New Sora Front and Rear Derailleurs. Of course we will get the right ones depending on if we go three ring or 2.

The crankset compatibility will depend on the chainring sizes. A 48/38/28 triple will likely fit. A 52/42/30 triple, however, probably will not clear the chain stays.

What shifters do you plan on using? MTB trigger shifters are not compatible with road front deraillers like the Sora model you are considering. A MTB FD derailler will shift to a 48T big ring with no problems. A 52 would require a road FD but you'll probably have to use a friction shifter to get it to work (even road flat bar shifters won't shift a true road FD properly).

the tapering for a sugino triple should be JIS, which is what shimano uses. Peugeot used 'french threaded BB' so yes, you will need to buy a new BB to use it on your rock hopper.
typically, you'd want a 113mm BB axle length for a sugino triple. It might have to be longer depending on how bowed your chainstays are.

We are using Suntour bar cons in friction mode, sora front derailleur (triple if we can make the crank work),Sora Rear derailleur (again, long cage if we can make the triple work), and a Shimano 12-26 cassette. I haven't counted the teeth on the crank from the older peugeot yet...It looks orginal, but in good shape. What size were the older Sugino cramks typically?

Just to clarify something here, there are two different factors at play, one is the threading of the bottom bracket cups, and the other is the taper of the spindle itself. The peugot likely has french threaded bottom bracket cups that will not fit into your frame. The spindle also likely has a different taper (ISO vs JIS). Long story short, it still won't work, but for many different reasons.

The Barcons can shift just about anything, so as long as your crank clears the frame you're good to go. It's always worth just giving it a try using the parts on hand. Both the Shimano crankset on the rockhopper and the Sugino on the Peugot should use JIS taper, and you have nothing to loose by throwing the triple on just to see if it fits.

If it bottoms out and the inner chainring rubs against the frame, then you need a new bottom bracket (Shimano UN-52, it's like $25) Otherwise you're good to go.

With friction Barcons, you don't really need to worry about derailer compatibility.

Thanks fuzz....that was super helpful....I am just gonna give it a try then with the crank and figure out if I need to a new BB if it doesn't clear. I am glad I got the Barcons. THey were the best part off the donated Peugeot.