[Shotimes] Questions about wheel diameter effect on fuel economy and acceleration

[Mark Nunnally]

Assuming the same dia (revs per mile) thus the same gearing, it's going to
come down to not just weight, but where the weight is.  A 40 lb tire/wheel
combo that has 15 lb on the wheel and 25 lb tire is going to accelerate (ie
spin up to speed with the same given amount of power as the other wheel)
slower than a 40 lb wheel/tire combo that has a 25 lb wheel and 15 lb tire,
since the wheel (closest to the axle centerline) is where the majority of
the weight is concentrated.  Ie you want the tire (ideally) to be as light
as possible (more-so than the wheel) since it's farther away from the axle
centerline, and is impacted by centrifugal leverage forces more-so than
something close to the axle centerline.

Same thing with going to larger dia wheels/tire, like from 15" to 17".
could be the same weight and revs per mile, but the 15" is going to make
more wheel hp all things being equal, also same with brakes.  Anybody every
watch the chessy (produced in canada) Sports Car Revolution on Speed?  They
stuck some big brakes and 17" wheels/tires on an acura, everything was
virtually the same weight as the stock pieces that came off, but they lost
like 11 wheel hp on the dyno.  Simply due to the larger dia brake and
wheel/tire pieces having more weight farther away from the axle centerline.

mark