Bmx Bicycle

Stamped steel chainring spider * Color: CHROME * Material: Steel * Chainring interface: 110mm bcd (Don't know what size Bolt Circle Diameter your existing chainring is? Measure center-to-center of two adjacent bolt holes on your chainring and then refer to this chart: http://www.sheldonbrown.com/cribsheet-bcd.html ) * Crank spindle size: 23.75mm (for one piece cranks) IMPORTANT - PLEASE READ: Chain alignment is unbelievably important for both YOUR SAFETY and performance/smoothness of the drivetrain. Because of this, we highly recommend all drivetrain products such as this be installed by a professional bicycle mechanic. If you choose to install this product yourself, be sure the chain is in exact alignment between the rear sprocket and the front sprocket.