i have measured and i believe i am gonna go with 20mm, just trying to get an idea of what to expect i can sort of see it in my head, but would rather see what it looks like for sure, i don't know weather to go 15mm or 20mm but thinking 20. i measure 20mm for the outside of the tire to be flush with the top of the fender i just want to see how far the tires will stick out at the bottom of the fenders.