Optimal gearing for spirited group rides and aggressive racingThe SHIMANO FC-RX610-2 balances weight savings and optimized efficiency for mixed-terrain riding and racing. Gearing options cater to the segmented demands of gravel cycling, maintaining the tighter gear steps needed to maintain your position in the bunch. The 2x12-speed crank utilizes a 46-30T chainring combination and comes in 165, 170, 172. 5, and 175 mm crank arm lengths.