Keith Bontrager (; born December 18, 1954) is a motorcycle racer who became a pioneer in the development of the modern mountain bike. Between 1980 and 1995, he was president of his own Bontrager Company, which continues to develop components for Trek Bicycle Corporation after Trek bought out Bontrager. Career Motorcycles Bontrager started in 1965 by building lawnmower engine powered mini-bikes. In 1969, he began racing motocross, funding his racing through motorcycle repair work. Between 1975 and 1981 he designed, built and tuned motocross, road racing and drag racing motorcycles. Motorcycles he tuned won national road racing titles in production and 250 GP classes. Bicycles In 1978 Bontrager became attracted to cycling and in 1979 built his first road bike. With his motocross background he was attracted to mountain bike cycling. In 1980 he built his first mountain bike frame and founded Bontrager Cycles in Sunnyvale, California. In 1984 he cut 700C (ISO 622) 36-hole Mavic MA-2 road rims to the circumference of a 26" rim, re-rolling them to create a 32-hole 26" rim. Bontrager rims were the first lightweight yet strong mountain bike rims, albeit using a profile intended for road racing bicycles. Mavic provided MA-40 MTB rims for some time. Bontrager went on designing lightweight rims, manufactured by Weinmann USA. Several were introduced but never went into high production because the Weinmann factory suffered a fire. The design of Bontrager frames was based on his studies at the University of California, Santa Cruz and experience as a motocross mechanic. While other manufacturers developed frames out of (oversized) aluminium, titanium, or carbon-fibre, Bontrager believed steel was not outdated but that its design and production could be improved. Joints could be strengthened by gussets to distribute loads and reduce the weakening of brazing and welding. He found areas in which joints could be made by bonding and riveting, i.e. the frames made between 1989 and 1994 had cable stops milled out of aluminum that were bonded and riveted to the top tube. Frames made at Bontrager's Santa Cruz workshop had two-piece seat stays made of larger diameter tubing in the upper area which added torsional stiffness around the brake-bosses, while the smaller tubes in the lower area reduced weight and vertical stiffness of the rear triangle leading to better damping of hits. Bontrager published articles on bicycle design and construction, ranging from the effects of TIG welding on the tubes