Plus Sizing Tires & Wheels
What Is Plus Sizing?
Simply put, plus sizing is when the size of the tires and/or wheels from the original size (Original Equipment, or OE) is increased. The idea is to maintain the same diameter and circumference as the OE setup to minimize changes in speedometer accuracy, traction, and power. This is also referred to as the 3% rule. As mentioned previously, plus sizing wheels and tires can help improve a car’s performance, including handling, stability, and traction.
It’s important to note that staying within the 3% variance is the safest route when plus sizing wheels and tires. However, there are unique situations where car enthusiasts use extreme wheel and tire fitments that require special modifications; such as suspension work.
Advantages and Disadvantages of Plus Sizing
Advantages
- Larger tires improve handling and cornering
- Wider tires may improve braking distances on dry pavement
- Wider tires may increase acceleration
- Plus sized wheels and tires can improve stability
- Larger wheels with low profile tires are considered aesthetically pleasing
Disadvantages
- Larger wheel and wider tires typically cost more
- Low profile tires tend to have stiffer sidewalls, which can impact ride quality
- Larger wheels and wider tires can negatively impact fuel efficiency and consumption
- Wider contact patch and surface area can increase ‘return to center’ steering characteristics after sharp turns
- Some people claim larger wheels and low profile sidewalls wear quicker
Plus Sizing Breakdown
Plus Zero
When the wheel’s diameter is unchanged and only the width of the wheel is increased, it is referred to as Plus Zero. For example, if you have a 18×9.5 wheel size and 255/45R18 tires, and you change the wheel size to a 18×10 and the tire size to a 265/45R18. As long as the diameter of the rim is unchanged, it is not considered a plus size.
Plus One
When the wheel’s diameter is increased by one inch, it is referred to as Plus One. This type of setup utilizes tires with an increased section width and lower aspect ratio. For example, a Plus One fitment for a car with 18-inch wheels would use 19-inch wheels. Generally, you want to follow these guidelines when Plus One plus sizing:
- Increase section width by 10mm
- Decrease aspect ratio by 10
- Increase wheel diameter by 1 inch
Plus Two
When the wheel’s diameter is increased by two inches, it is referred to as Plus Two. This type of setup utilizes tires with an increased section width and lower aspect ratio. For example, a Plus Two fitment for a car with 18-inch wheels would use 20-inch wheels. Generally, you want to follow these guidelines when Plus Two plus sizing:
- Increase section width by 20mm
- Decrease aspect ratio by 20
- Increase wheel diameter by 2 inches
Plus Three
When the wheel’s diameter is increased by three inches, it is referred to as Plus Three. This type of setup utilizes tires with an increased section width and lower aspect ratio. For example, a Plus Three fitment for a car with 18-inch wheels would use 21-inch wheels. Generally, you want to follow these guidelines when Plus Three plus sizing:
- Increase section width by 30mm
- Decrease aspect ratio by 30
- Increase wheel diameter by 3 inches
Conclusion
In the end, it’s important to make sure to choose the right tires when plus sizing. Lionhart Tires offers a wide selection of tire choices, from OE replacements to plus sizing options. Check out our collection of tires and then work with a tire professional to find the right wheel and tire setup that suits your needs.
