OSSA 250 Monocoque

OSSA 250 Monocoque

By guest writer Richard Fowler of Motorsport Retro. This amazing little OSSA 250cc Grand Prix bike finished 3rd in the 250cc World Championship in 1969. Its revolutionary monocoque stunned the Grand Prix paddock, yet the clearly superior design never found favour with the big manufacturers. Designed by Eduardo Giró, the son of OSSA founder Manuel Giró, the bike featured a six-speed gearbox mated to a single cylinder, 250 cc two-stroke rotary valve engine. It produced a modest 30 hp. The engine was no match for the fire-breathing V4 Yamahas of Phil Read and Billy Ivy, but with its clever magnesium monocoque chassis, the bike weighed a full 20 kg (44 lbs) less than the class-leading Japanese competition. Riding the bike was young Spanish superstar Santiago Herrero, who soon showed the world that despite its power deficit, the advantages of the innovative chassis were sufficient to bring the small team Grand Prix victories. Herrero reveled in the OSSA’s superior cornering and braking ability, throwing the OSSA into corners like it was a 125 cc lightweight. He was able to carry more speed whilst being super-accurate, and slice up the inside of his competitors under braking. It was all due to the monocoque superior chassis stiffness and weight. The 1969 campaign saw Herrero and the team win three Grands Prix against the previously unbeatable Yamahas and he led the Championship going into the final race—until a crash ended his title hopes. The tiny Spanish OSSA team again led the Championship in 1970, until Herrero crashed fatally at Isle of Man TT. Devastated by his death, the OSSA team immediately withdrew from road racing, never to compete again.