max speed drivetrain on 126mm spread?
 

I just spread a 126mm frame to 130mm, but I noticed that the rear stays of 9-speed bikes are shaped/bent a little differently, and a few people have told me that this is to allow for a 9 speed rear cassette. Is there a maximum speed drivetrain that can be accomodated by the old style of stays?

I have 7-speed running on my 126mm Fuji and just for fun I put my spare Shimano WH-RS10 wheel with a 10-speed 11-23 cassette on it (spread by hand...wasn't too hard) and had plenty of clearance. I'd imagine I would have had enough with a 12T small cog too. Bigger than that? I dunno.

Shimano introduced the 8 speed cassette with 130mm spacing about 88 or 89. Back then there were no bike mfrs. making 130mm spaced rear ends. Shimano designed the first 130mm hub to be forced into 126mm stays. After all each stay is only 2mm on each side. Once you have the 130mm hub in, you can run 8, 8, 9, or 10 speeds.

Without coldset spreading, 126mm = 7 speed, max, with narrow chain. From there, spread as much as you can or dare...?? Steel frames only, of course.

Chombi

10 w/ a Dura Ace hub. Axle spacing needs to be tweaked.