A regular trend that started on the Fourtrax that would not carry over to the four strokes was the use of aftermarket frames. Stock frames on most mass-produced quads are made of mild steel and, though suitable for recreational use, will quickly develop cracks when raced. Without new quads available after the 1989 model year, stronger replacement frames for racing were soon needed. The first aftermarket frame for the 250R was made by dirt track motorcycle chassis builder, C&J in 1991 for CT Racing.This frame was a direct replacement for the original, maintaining stock suspension geometry. The first altered geometry frame was introduced by JP Racing a short while later. [3 This design brought the front suspension mounts in one inch on each side, allowing the use of longer suspension arms in competition, which increased wheel travel and improved the ride qualities. By 2003, a myriad of aftermarket frames could be had from numerous manufacturers in both stock and altered geometry, made of steel and aluminum. Lone Star Racing produced a titanium frame, but AMA rules prevented its use in competition.