Biker culture is culture related to motorcycles. It is often linked with the leather subculture due to the protective outfit - which may also involve chains. Biker culture is concentrated around legendary motorcycle brands such as Harley-Davidson, Royal Enfield and BSA. Some people relate biker culture to speed freaks riding modern, high-speed motorcycles made of plastic, but the truth is that "real bikers" love the tremendous ground-shaking sound of big V2 engine rather than the sound of high-rpm four-cylinder engine.