In the automotive world there is a concept known as “plus sizing” of wheels. The concept is basic, if you have a vehicle with 18-inch wheels, plus one would be a 19-inch wheel and plus two would be 20 inches. Moving to a 20-inch wheel from 18 inches can provide several advantages.
A 20-inch wheel has less tire sidewall and more wheel showing than an 18-inch wheel, which can be more visually appealing.
When swapping from an 18-inch wheel to a 20-inch, a tire with a smaller sidewall will be required. This smaller sidewall will provide your vehicle with improved handling characteristics but will also come at the cost of a harsher ride.
If you have 18-inch steel wheels, upgrading to 20-inch alloy wheels could save weight, which improves the steering response and cornering of the vehicle. The lighter rotational weight also could provide a small increase in acceleration.
Cooling of Brakes
Alloy wheels act as an excellent heat conductor and can help brakes dissipate their heat more efficiently. Cooler operating temperatures can reduce brake fade and improve the responsiveness of the brakes under extreme conditions.