BMW Type 255 Kompressor

Manufacturer	BMW Motorrad
Also called	Type 255 RS 500
Production	1935–1939[1]
Predecessor	BMW WR 750
Class	Street racing
Engine	492.6 cc (30.06 cu in) DOHC supercharged boxer twin with aluminium cylinders; magnesium engine block and supercharger casing[2] Fuel: gasoline-oil mix
Bore / stroke	66 mm × 72 mm (2.6 in × 2.8 in)[1]
Top speed	c. 220 km/h (140 mph)[2]
Power	60 hp (45 kW)[2]
Transmission	4-speed, shaft drive[1]
Frame type	Tubular steel twin cradle
Suspension	Front: Oil-filled telescopic forks Rear: Rigid (1935–1936) Plunger (after 1936)[1]
Weight	138 kg (304 lb)[2] (wet)

BMW Type 255 Kompressor (also known as the 500 Kompressor, RS 255, RS255 and Type 255 RS 500) was a supercharged boxer twin race motorcycle from the 1930s. A BMW 255 Kompressor was ridden to victory by Georg Meier in the 1939 Isle of Man TT and the first win by a non-British competitor in the premier 500cc Senior TT class.^[3] A similar BMW 255 Kompressor machine was auctioned in 2013 for US$480,000, the second-highest price ever paid at auction for a motorcycle.^[4][5][6]

Supercharger

A Zoller sliding vane supercharger is bolted to the front of the DOHC engine, driven directly by the crankshaft, and is lubricated by castor oil added to the fuel.^[1][2][7] It provided c. 15 psi (100 kPa).^[1]

Records

The machine set a number of race records, including the first lap over 100 miles per hour (160 km/h) at a major event, when Georg Meier won the Belgian motorcycle Grand Prix in 1939, and Ernst Jakob Henne's capture of the motorcycle land-speed record in 1936 on a model with a streamlined fairing.^[1]

Today

An example is on display at the BMW Museum in Munich.^[8]

Further reading

• 1939 BMW "Kompressor" Tourist Trophy 1–2 Victory June, 2009 BMW press release via WebBikeWorld
• Extensive model information at Bonhams (prior to January, 2013 auction)
• Blake Z. Rong (January 22, 2013), In Las Vegas, a gamble on BMW's Kompressor and McQueen's Husky: Bonhams Motorcycle Auction provides plenty of surprises, Autoweek

References

External links

• Media related to BMW RS500 at Wikimedia Commons