Tires: Your Biggest Bang for the Buck

Except for the driver, tires are the single most important performance component on your car. A tire upgrade will produce the biggest bang for your car-modifying bucks.


A move from, say, an all-season touring tire to a high-performance summer tire will reap huge rewards in responsiveness and traction. (Ride comfort might suffer a little, but there's no free lunch.) This is true even with the same size tire. The "all-season" moniker means a tire gives up wet and dry grip to get increased mobility in snow. All-season tires have LESS grip—wet or dry—than an equivalent summer tire.

Combo Pack
If you're planning on replacing wheels and tires at the same time, get a combined package—a mounted unit in tire-speak—that duplicates the stock package in overall diameter, total weight, and wheel offset. A wheel/tire combo with a different offset or larger mass will seriously upset some suspensions. A wider tire with a shorter overall diameter will put LESS rubber on the road. At the least, a different diameter will make your speedometer inaccurate. You'd hate to spend all that money and effort for something that makes the car worse than stock.


If you've got your heart set on a stylish set of wheels, consider a "plus one or plus two" upgrade. This means the tires' aspect ratio (also known as "profile") is reduced while wheel diameter is increased in order to retain the same overall diameter of the mounted tire. You can also increase tread width while retaining overall diameter if you reduce aspect ratio.

Aspect Ratio
Aspect ratio is, oversimplified, the relationship of the tread width to the sidewall height: In a 225/55R16, the sidewall is 55 percent as tall as the tread is wide—and the tire is mounted on a 16-inch diameter wheel. With this example, if you step up to 17-inch diameter wheels you could either select a 225/50R17 and retain the same diameter and width. Or, if you car offers enough clearance, you could move to a wider 245/45R17 and still retain the same overall diameter.