Wheel and Tire Selection

If you are thinking about putting different rim/tire combo on your V6 Mustang, you might want to consider the information presented below.  

Wheel Weight

           

 Wheel
size
Wheel
weight
Tire
size
Tire
weight
Total
weight
Weight
difference
A15"x7"x24mm16.1 lb205/65/1521 lb37 lb--
A15"x7"x24mm16.1 lb225/60/15 25 lb41 lb+4 lb
B16"x7.5"x30mm17.55 lb225/55/1626 lb43.5 lb+6.5 lb
B16"x7.5"x30mm17.55 lb245/50/1628 lb45.5 lb+8.5 lb
C17"x8"x30mm22 lb245/45/1726 lb48 lb+11 lb
C17"x8"x30mm22 lb275/40/1728 lb50 lb+13 lb
D17"x9"x26mm25 lb275/40/1728 lb53 lb+16 lb

The '94-00 base Mustang came with 205/65/15 tires on 15"x7" cast alloy rims (about 37 lbs per wheel).   Starting in '00 you could also get 225x55/16 tires on 16x7.5" forged alloy rims (about 43.5 lbs per wheel).   That combination became standard equipment in '01.   Ford apparently decided that the 99+ cars could handle an additional 6.5 lbs of wheel weight without any noticeable change in the car's performance.   But there is no question that heavier wheels produce a performance loss.   They are harder for the engine to turn, for the suspension to control, and for the brakes to stop. Heavier wheels slow acceleration and produce longer stopping distances.

Tirerack.com measured the performance of a BMW 3-series sedan with its stock 16x7 wheel/tire combo and then with a 17x8 wheel/tire combo that weighed 7 lbs more per wheel.   The addition of 7 lbs of wheel weight resulted in a deterioration in the car's handling, a measurable increase in its lap times and a 1.7 mpg drop in its average miles per gallon.   Conversely, when they installed lightweight rims that reduced the car's road wheel weight, the car's performance (gas mileage, etc.) improved.

Wheel Width vs Tread Width

In addition to considering wheel weight, you should think about what tire tread width will work best on your new wheels.   The fact that a tire will fit on a wheel is no guarantee it will work effectively on that wheel.   Radial tires are very sensitive to wheel width.   A good rule of thumb is to select a tire with tread width that is within ± 1/2 inch of the the wheel width.   If you are serious about corner carving, you should lean toward a tread width that is equal to or a bit less than the wheel width.

My Wheel & Tire Selection

In June 2005 I removed the 15x7" cast alloy machine-finish wheels with 225/60/15 tires that had been on my car for five years.   I replaced them with new 16x7.5" forged machine-finish wheels that I picked up cheap on ebay.com, and some Bridgestone Potenza RE750 tires.   Not a very exciting upgrade, I'll admit.   But the issues are the same regardless of your choice of wheels and tires.

Bridgestone Potenza RE750
 245/50/ZR16225/55/ZR16
Tire diameter25.7"25.7"
Tire weight28 lbs. 26 lbs.
Wheel width range7-8.5"6-8"
Section width9.9"9.1"
Tread width7.9"7.2"

As you can see in the chart above, the Potenzas are available in two sizes that are close to the Mustang's stock tire diameter and suitable for use on a 16x7.5" wheel.   I chose to go with the 225/55/ZR16's because that wheel-tire combination only weighs about 2.5 lbs per wheel more than my old 15x7" wheels and tires. The 225's also have a tread width that is slightly less than my new wheel width.   If I had gone with the 245's, I would have added 4.5 lbs of weight per wheel and had a tread width that exceeded my wheel width.   I did not want that.   You might have selected a completely different wheel-tire combination.   That's o.k.   The sole purpose of this article is to help you make your own informed decision.

Addendum: Where did I get these numbers in this article?   The 15" and 16" wheel weights come from weighing my own wheels on a postal scale.   The rest of the numbers come from Ford wheel catalogs and tire company spec sheets which are widely available on-line (e.g., at tirerack.com).

miracerros@comcast.net