- Joined
- Mar 12, 2013
- Messages
- 322

Most are aware that horsepower measured at the crankshaft will be greater than that measured at the rear wheel, but no one seems to have any idea exactly what the loss is, and whether the loss is greater with a primary chain than it is with a belt drive? To properly evaluate this, either a water brake, or an eddy current dynamometer is required, the loss cannot be calculated/guestimated from a rolling road test. I am particularly intrigued by this because most rear wheel horsepower would seem to be highly optimistic. Phil Irving was once asked this question obout the Vincent, and said that he had never measured it, but would estimate it to be in the region of 10%.
Of course the outcome could depend on what gearbox was used, some boxes being more efficient than others, and in the case of the Japanese multi cylinder machines, the all enclosed gear primary drive has to be taken into account, although these machines hardly lend them selves to having their power measured at the crank.
Has anyone ever taken the trouble to find out?
Of course the outcome could depend on what gearbox was used, some boxes being more efficient than others, and in the case of the Japanese multi cylinder machines, the all enclosed gear primary drive has to be taken into account, although these machines hardly lend them selves to having their power measured at the crank.
Has anyone ever taken the trouble to find out?