The Annex Pro model takes things to the next level in multiple ways. Starting off with a 20.5" top tube 6061 alloy frame which has larger geometry and tubing than that found on the Expert model. 8" rise bars and 100% chromoly fork with 1 1/8" steer tube provide adequate size and strength for proper front end control. The Annex Pro also comes with 175mm 3 piece chromoly cranks and full sized 20" 36 spoke alloy wheels which increase strength and are versatile for riding/racing at the BMX track and all around riding.