Strugglin a little to get a decent chainline on my Iro Mark V.

First off all, my 107mm Miche JIS BB kept the chainring very far from the BB shell and making a horrible cross to get to my Grancompe in the rear wheel.

Then, i assumed it could work puting a ISO crankset on my Miche JIS since JIS are a little thinner than ISOS so the crank set could go in a little more to improve the chainline. Not worked since the left arm touched a lot the BB cup.

NOW i took the Miche off and put some cheap 103mm ISO in and my ISO cranks (from the second attempt), both from my other bike, and the chainline got really good BUT another issue appeared: the current chainring on the cranks are 45t and this guy, LITTLE AS THIS IS almost touches the straight chainstay, having like 3mm to scratch the tube, SO, i should FORGET to get this cranks a bigger plate.

Bottom line: what are my chances so i can use a 47/49 chainring in this bike?? 107mm makes cross chain line, 103mm a little plate almost gets the tube.

I`m thinking about to aks a framebuilder friend to knead a little the chainstay tube in the contact poing to get some space for bigger plates, like the old steel frames where before the bent tubes of new ones.

Thanks!

M.

If your current BB doesn't have a lip on the NDS cup, you could try adding a 0.5mm BB spacer between the DS cup and the frame to scootch the crankset to the right a little. 3mm of clearance isn't bad if your chainring runs true, though.

The Miche Advanced track crank uses a 107mm ISO spindle, not JIS (yes, I know the Miche site says JIS. It's incorrect).

If you stop screwing around and just use the right BB, you most likely won't have any trouble.

I'm surprised that the website says JIS. How could a company like Miche make such a critical error?