IM AT A2 WITH 28 DOUGLAS MOAPA RUN FLATS, HUGH IMPROVMENT OVER B2, LIKE NIGHT AND DAY, YOU WILL LOOSE ABOUT 10 MPH BUT THE POWER RANGE IS WHERE IT NEEDS TO BE WE RIDE MOUNTAINS MOST THE TIME, RAN APROX 68 MPH NOW RUNS 59 EST NO PROBLEMS FOR MY TYPE OF RIDING, I WILL GET RPMS UP INTO PROPER POWER RANGE. ALSO THE RUN FLAT TIRES ARE HEAVY APROX 45 LBS EACH DONT THINK I NEED TO GO ANY MORE ON SECONDARY CLUTCH BECAUSE IT WOULD PUT RPMS TO HIGH ON CRUSING