Brake Horsepower (bhp) and kW

Brake horsepower (bhp) is the power an engine delivers at its crankshaft, originally measured by loading the engine with a brake on a dynamometer. It is the usable output before losses in the gearbox and final drive.

Units can be confusing. In Europe the official unit is the kilowatt (kW), shown in registration papers. Manufacturers also quote metric horsepower (PS or hp), where 1 kW is about 1.36 PS, while the imperial horsepower used in the UK and USA is slightly larger, so 1 kW is about 1.34 bhp.

A rear-wheel dyno measures wheel horsepower, typically noticeably lower than crankshaft figures because of drivetrain losses. When comparing bikes, make sure the figures come from the same kind of measurement. Licence categories such as A2 are defined in kW.