[Shazaam!]

How about a free front magnesium wheel with your next tire purchase?

Consider this:

3.5 x 17 Wheel Weights:

Ducati OEM aluminum 5-spoke .... 9.25 lbs
Marchesini magnesium 5-spoke ... 6.80 lbs
Weight Savings ................. 2.45 lbs


120/70ZR17 Tire Weights (Sport Rider Magazine June 2002)

Dunlop D207RR ............... 10.44 lbs
Pirelli Supercorsa............. 8.38 lbs
Weight Savings ................. 2.06 lbs

Dunlop D207RR ............... 10.44 lbs
Bridgestone BT-010 .......... 8.81 lbs
Weight Savings ................. 1.63 lbs

This seemingly small weight difference between the heaviest Dunlops and the lightest Pirellis or Bridgestones is even more important than a larger weight savings at the wheel.

Simply stated, the rotational inertia of a wheel or tire is proportional to the square of the distance the weight is placed from the axle. Because of this square-effect, the tire weight has more effect on the rotational inertia of the wheel-tire combination mainly because of its somewhat greater distance from the axle.

A 1.6 - 2 lbs. lighter front tire will give you the same handling improvement that you get by switching from an aluminum to a magnesium wheel.

Looking at it another way, you can negate the handling benefits of expensive light weight wheels by switching to a heavier tire.

This is also the best argument for choosing aftermarket wheels that have carbon fiber rims. When compared to all-magnesium wheels with the same weight, a carbon fiber rimmed wheel will have significantly lower rotational inertia that results in improved acceleration and handling.

(The similar construction of rear tires results in weight savings of less than a pound so you'll see a lesser improvement effect there.)

I'm not saying that tires should be chosen based on weight alone but given the very similar performance of high performance street tires, why not take the free mag wheel?