Effect of Wheel Size on Your Car

Is Bigger Better? The Effect of Wheel Size on Your Car

Plus-sizing your wheels and tires is an easy way to upgrade a vehicle's look. As a wheel gets larger in diameter, the tire's sidewall must necessarily shrink to maintain the same profile. These larger alloy wheels with their shorter tire sidewalls have bold visual appeal. Bigger tires and wheels look cool, no doubt about it. But what is the effect of wheel size on your car? And does a bigger wheel add anything to your vehicle's performance?

Typically, someone wishing to plus-size starts from a 15- or 16-inch standard wheel size and upgrades to a 17-, 18- or 19-inch diameter. As wheel size increases, tire diameter decreases to maintain the same overall diameter, ensuring proper clearance, gearing and speedometer readings. Large diameter wheels and tires are often only available in increased widths, so plus-sizers must take their wheel well and fender depth into consideration as well. A manufacturer's car wheel size guide can help determine what sizes will fit your make and model.

As to performance, increasing the size of your wheels has both benefits and drawbacks. On the plus side, tires with shorter sidewalls can improve steering response and cornering stability. Increasing the wheel diameter and width may also increase traction. On the downside, larger tires mean more weight. More weight hurts fuel efficiency, acceleration and stopping distance. Wider tires have a tendency to float, reducing traction in inclement weather. Perhaps the biggest downside to plus-sizing is the reduced durability of the tires themselves. Narrow tire sidewalls don't have the strength of standard tires and can be damaged by potholes and road debris. They can also sustain damage from getting pinched more easily.

Numerous wheel size comparison road tests give 17-inch and 18-inch wheels and tires the highest ratings, citing good grip, steering, braking and a comfortable feel. Upgrading from a 17- to 18-inch diameter had negligible effects on ride quality and offered additional grip. Heavy 19-inch wheels and tires fared the worst in road tests, straining the suspension and increasing impact harshness. In contrast, 15- and 16-inch standard wheel sizes were the quietest and had the smoothest ride, but had slightly more understeer on the skidpad.