Renthal Final Drive Kit (428 Conversion) K045 Kit includes front and rear sprocket with same gear ratios as stock and a Gold Renthal R1-428 chain Saves over 2 lbs. over the stock 520 O-ring chain and steel rear sprocket Improves acceleration and responsiveness with less revolving un-sprung weight Front sprocket is made from super strong nickel chromoly and is grooved to clear mud and increase chain life Rear sprocket is made from 7075 T-6 aluminum which is precision machined with self-cleaning mud grooves and lightening holes