The Harley-Davidson VRSC (V-Twin Racing Street Custom) household of cruiser motorbikes was introduced in 2001 in a single model called the V-Rod. The V-Rod was developed by Harley-Davidson to compete against American and japanese muscle bikes. The "V-Rod" utilized the Revolution engine, developed jointly with Porsche that, for the very first time in Harley public manufacturing history, showcases overhead cams and liquid cooling. The V-Rod is aesthetically distinct from other Harley-Davidson motorcycles. It can be easily identified by the 60-degree V-twin engine, the radiator and the hydroformed frame members that support the round-topped air cleaner cover. An unique distinction in between the V-Rod and all other Harley production motorcycles is the location of the fuel tank. The fuel tank on the V-Rod is located underneath the seat, putting the rider on top of it, instead of the usual frontal placement. The "tank" in this case is simple dressing, hiding the frame. Freely based upon the VR-1000 superbike, it continues to be a platform around which Harley-Davidson constructs drag-racing competitors devices.