Education on wheels needed (vehicle, tire, roadster, difference)

[banger]

Several months ago, I scratched my itch for a new roadster and bought a new B.M.W. Z-4, all well and good. Great car, no problems.

Now for the question,

Reading the forums, people frequently express concerns over wheel weight, tire weight, sprung weight, unsprung, etc..

Some of these guys aparrently go nuts over one wheel being 3-5 pounds heavier than another.

WHY ???, Given that a vehicle weighs thousands of pounds, how can 30 or so pounds make any difference?

[Titan 3]

Unsprung weight is the bigger deal, as it is rotational mass. It's two very different things for the car to "carry" weight (sprung) and try to rotate it (un-sprung). As a result car heads tend to lean towards a lighter wheel. Less weight anywhere in the car is great, but rotational mass really effects your launch.

BTW.... Welcome to the club! You'll never drive anything else again!