Mongoose 21 top tube full 4130 chromoly bmx frame with an integrated headset provides a strong reliable ride with todays popular geometry trusted by the pros giving you a top notch bike the 25 9t gearing with cassette driver and durable 3 piece tubular cromo 175 mm cranks are attached to a 48 spline spindle and spin smoothly with a sealed mid bb 36 hole double wall wide alloy rims keep the wheels true and rolling smoothly the dependable mongoose full chromoly forks and 875 bars are a