Complex sentence: In 1980 he built his first mountain bike frame and founded Bontrager Cycles, out of Sunnyvale, California, offering custom road, track, tandem and mountain bike frames.
Split into simpler sentences: In 1980 he built his first mountain bike frame. It was also this year that he started Bontrager Cycles, out of Sunnyvale, California, offering custom road, track, tandem and mountain bike frames.