Custom Wheels 3
What Is Plus-Sizing?
When considering a larger diameter wheel, your goal is likely to maintain the same overall total diameter of your new wheel/tire package. This helps with speedometer accuracy, greatly maintains factory handling and braking, and negates the need for any other vehicle modifications.
This concept of increasing wheel diameter is called "Plus-Sizing". A plus one upgrade means the rim increases one inch in diameter, while a plus two reflects a rim diameter increase of two inches - and so on. But in order to maintain the same approximate tire diameter, the sidewall of the tire must become shorter as the wheel diameter is increased.