I have a sunn S1 modular frame, which when i bought it, could not have the SRAM crankset specified as the chainrings were hitting the chainstay. To cut a long story short, the bike was supplied with a different set, a deore FC M615 double crank. Even with this crank there was only about 1 mm clearance between the ring mounted in the outer double position and the chainstay. What is an acceptable chainstay clearance?

The front rings are getting worn, so ive decided to go for a 32T oval absolute black front ring and use an SLX M665 double crankset i have. When Mounting the oval ring in the outer double position on the SLX, the chainring hits the chainstay. Using a 32T regular chainring i have has less than 1mm clearance. What is going on here? Do i have to space out the bottom bracket, which is a push fit ( that i am unfamiliar with), or have i got a frame that seems to be incompatable with some hollowtech 2 cranksets What is the difference between the deore FC M615 and SLX M665 cranksets — surely both being shimano, they should both fit?

Puzzled as i havent ever come across this before