S&M Challenger Frame KitThe S&M Challenger frame is one of the best selling BMX frames ever and a hallmark of S&M Bikes being the go to BMX brand. Beautifully built and re released for the BMX collector, the S&M Challenger Frame Kit features both S&M frame and fork, as well as a 1" threaded headset and 1" seatpost clamp. From the March 1994 S&M Action catalog: The new Challenger frame has become a pretty hot number with avante garde hot dogs across the U. S. of A. Its