|
aerohead is right, polar moment of inertial is the acceleration/deceleration "weight" that heavier tires & wheels saddle you with.
The trick with polar moment is that it isn't only weight, but where the weight is relative to the rotational axis that is important. Say you had a 40 lb tire/wheel combo that was shaped like this: <> only taller/skinnier like a soap box derby car, it would have a much lower polar moment of inertia than a 40 lb tire/wheel combo shaped like an I.
The trick is to keep the mass as close to the rotational axis as possible. This is the reason that going to larger diameter wheels can drastically affect your mileage and acceleration time even if the tire OD stays the same, the tire weight is pretty constant but with a lower aspect ratio that mass is concentrated further from the rotational axis thereby increasing your polar moment of inertia.
__________________
|