I have a vintage TA double crankset - 48/34 rings - and I'm building up a bike with a Suntour Cyclone 7000 6-speed set up on the back.
When cross-chaining from the small chain ring to the smallest sprocket on the freewheel, the chain rubs on the inside of the outer chainring.
I've tried wider BBs - up to 123mm - and spacers but still have the problem. Rear dropouts are 124mm spacing and the rear wheel dish is spot on. Is this just something I'm going to have to live with, and avoid cross-chaining, or is there a simple solution to the problem that I'm missing?
I use the same crankset on other vintage bikes with 5-speed freewheels and have no problems but the 6-speed is considerably wider. Maybe its the narrow Q of the crankset that makes it unsuited to this set-up?