So everyone with a Grom knows that they hardly pull 4th gear stock. Even big bores can benefit from swapping out that 4th gear, and Kitaco has come up with a nice ratio kit. Changes stock 4th gear from 0.923 to 1.000, just steep enough to pull the revs. Even our 5 speed race trannys run 1.00 for 5th. Gears come molybdenum coated for longer life and smoother shifts.