>Wheel diameter does matter. A wider wheel puts the mass
>further away from the center, which decreases the legerage
>over it, and slows down a car.

agree to a point. slows the cars acceleration down but helps top speed because the weight is farther away from the center. inertia works in your favor during acceleration.

>A wheel with a lighter overall
>weight can wind up acting heavier then a heavier wheel, if the
>lighter wheel has it's mass further from the point of
>rotation. The principle is the same as lifting a 10 lb weight.
>If you put the weight on your arm near your shoulder, it is
>easy to lift. Put the 10 lb weight in your hand and keep your
>arm straight, and it is fucking heavy! Same principle applies,
>except that the arm is a continuous circle.

disagree. the movement of the circumfrence of a car's wheel is not the same as the movement of lifting a ten pound weight. a more accurate analogy would be locking your elbow and swinging your arm in a circle while holding the weight. this is still somewhat inaccurate because the spokes of a wheel act as an arm connecting it to the weight at the circuference and the weight is more evenly distributed throughout the circuference of the wheel where swinging your arm with a weight would have one spoke with the weight focused at only the end of that single spoke. having a lighter wheel would mean reducing the weight at the end of the many spokes which makes spinning the wheel easier.

>Also, gearing is affected by wheel and tyre choice. I know that >Todd's gearing is different then mine (although not by a whole lot), >but the rotational inertial is what kept me slower then him until
>now.
>-=B=-

agree here too.