Automakers use king-size wheels on their concept cars because they give them a more aggressive stance. They are cool.

There are pros and cons to choosing larger wheels, whether you’re looking to upgrade to a larger wheel for a new car or to replace your existing wheels. You will need to purchase new tires if you change to a larger diameter wheel (such as 17-18 inches). These tires require a lower profile (or sidewall elevation) in order to provide adequate clearance for the tire when it goes over potholes. This allows the suspension to fully compress and rebound. To compensate for an increase in wheel diameter, the tire’s height should be decreased by 1 inch.

If your original stock tire size was 215/65R17, and you purchase 18-inch wheels, then the correct tire size might be 225/55R18. The differences are the larger wheel size, wider tread (265 millimeters instead 215) and lower profile (55 instead of 65). This means that the tread’s width is 55 percent higher than the sidewall.

Changing to larger wheels without considering sidewall height will not only cause damage to the suspension and tires but also result in incorrect speedometer readings as the wheels are turning at an altered speed. If you match lower-profile tires to larger-diameter wheels, your speedometer and odometer readings will only change a little, if any. Larger wheels with lower profile tires and correspondingly shorter sidewalls mean that they are stiffer and have less air and rubber cushion. This increases the likelihood of hitting large potholes, which could cause serious damage to the tire, wheel, or both.

Larger-diameter tires and wheels will improve handling and performance at high speeds, but lower-profile tires have a firmer ride and can be noisier that the standard rubber.

The additional weight of larger tires and wheels may negate some potential performance gains. For example, an 18-inch tire will likely weigh at least two to three pounds more than a 16 or 17-inch one. This could also hold true for larger wheels. Steel wheels weigh more than aluminum alloy wheels, which means that they perform better by decreasing the unsprung weight. A standard 17-inch alloy wheel will be replaced with an 18-inch or 19-inch alloy hub. This is unless the rim is lightweight and expensive.

Larger wheels are more expensive. The more you buy, the more expensive your tires and wheels will be. The initial cost of larger wheels may be lower if you get them as standard equipment or as an option on a new car. The extra cost of replacing damaged wheels or tires (or simply the replacement tires when the tread has worn) can add up quickly.

Cars.com examined the costs of replacing some wheels and tires. For example, a 16-inch standard steel wheel on a Toyota Camry cost $172 to replace at an authorized dealer. The cost of a 17-inch alloy wheel on a Camry XLE was $379. One dealer offered us an 18-inch alloy wheel on a Chevrolet Traverse for $371. However, we were quoted $569 for an optional 20 inch wheel.