The crank SHIMANO FC-RX820-1 offers a balanced ratio between weight savings, optimized efficiency, and a range of gear options that meet the different demands of riding in mixed terrain. By combining a 10-45Z or 10-51Z cassette with a 40Z or 42Z chainring, a closer gear spacing or maximum range can be selected according to preference. The FC-RX820-1 is available in crank arm lengths of 170, 172.5, and 175 mm, providing an additional option for customization.