I think you are right. I knew that 1" increase of pitch lowers your RPM by 200rpms, but I didn't think to see what the calculation for diameter was.
Apparently 1/4" of diameter increase lowers your RPMs by 200.
If I go to a 13.75x15 that should put me at 5400 RPMs, which would be good. 14x17 would drop me to 4800, no bueno.
|