The Colony Menace Guard is a high performance BMX freestyle bike converter. Available in 25T and 28T versions. If you want to achieve higher top speeds, choose a larger chainring with more teeth. However, if you want easier pedaling and better acceleration, then you should choose a smaller chainring. This Colony derailleur is designed with a 24mm center hole and screw hole, but with the included adapters it is also suitable for 19mm and 22mm mounting.