The ACS Main Drive Freewheel is a dependable replacement option for most BMX, fixed gear, and single speed bikes, offering similar performance to original equipment on many new models. It uses a dual-pawl system that engages every 18 degrees, providing reliable function for casual riding applications. Designed to thread onto standard 1.375″-24tpi hubs, it is compatible with most setups using 16-tooth or larger freewheels. The 1/2″ x 1/8″ sprocket pitch pairs with 1/8″ wide single speed chains but is not compatible with 3/32″ chains. Featuring a 4-notch interface, the Main Drive Freewheel is easily removed using ACS or other universal freewheel removal tools. This freewheel is not recommended for motor conversions, jack shafts, or high-torque use.