I just bought a 13t and 14t cb and also a 47, 49 and 52t spur gears so I can run some other options. I'm thinking about running the 14t cb and the 47t spur. I have a .18 CV-R. I am running the 2 speed now and second gear is 16t cb and 49t spur and it will easily spin out shifting into second gear on pavement. 1st gear is 13t cb and 52t spur and I can't get traction period. Makes for driving on dirt tricky.