John Surtees, the only man ever to win world titles on 2 & 4 wheels
http://www.bbc.co.uk/sport/formula1/39235608
I was fortunate enough to see both John Surtees and "Mike the bike" Hailwood race at Watkins Glen back in the 70's in Formula 1. To be able to win on 2 wheels and 4 takes a real talent that no one else can do. Surtees did suffer some injuries, but was able to survive in the most dangerous era of racing. Surtees was still "racing" at the Goodwood Festival of Speed when he was 80 years old.