17" rims/ power loss?

Originally posted by 94_AcCoRd_EX
About the power output... I was thinking the same thing, but it does affect the hp put down to the wheels. An issue of SCC put a civic on the dyno and it lost up to 5 hp with very heavy wheels. I might have it somewhere, if I do, I'll post the explanation.

Hmm... how does a dyno measure power? I'm guessing it knows it's resistance (torque required to spin it) and your acceleration (measured), so it can calculate the power output to the wheels. Maybe it assumes an unsprung weight? It seems that even if there was *no* dyno resistance (frictionless dyno?) power would still be required to accelerate the wheels (and more power for a higher wheel inertial moment) - maybe the difference in wheel mass is ignored.