How to Change Low Profile Tires to Regular Tiresby Justan Brandt
If your vehicle has low profile tires--which offer a small amount of sidewall height--and you wish to replace them with ones that features higher side walls, you will need to decrease the size of your wheel diameter. Most professionals suggest that your new tire and wheel combination be within a 3 percent, positive or negative, variance of the original equipment.
Reading Tire Size
Find the size markings on your tire. An example: 245/50R19
Consider the first number. "245" represents the width across the tire, in millimeters, at the widest point.
Look at the second number. "50" represents the height of the tire’s sidewall, from rim to tread, as a percentage of the tire width. In this case, the tire’s height would be 122.5 millimeters, which is 50 percent of 245 millimeters. This is also known as the tire’s series.
Consider the final number "19" represents the wheel diameter, in inches, that the tire is intended to be mounted on.
Do the math
Calculate the overall tire height, in inches, using the following formula: ((Width/25.4)*sidewall percentage as a decimal)*2 A 245/50R19 tire would have an overall tire height of 9.64 inches: ((245/25.4)*0.5)*2).
Combine the overall tire height with the wheel diameter to reach the final diameter of the wheel and tire combination. Using the previous example, add 9.64 to 19 for a final diameter of 28.64 inches.
Maintain the 3 percent variance rule. You can install a new wheel and tire combination that is anywhere from 27.78 inches to 29.50 inches in total diameter.
- Ensure the internal diameter of your new wheels clear your brake calipers and have the correct width and offset for your vehicle as well.
Justan Brandt became a journalist and writer who specializes in automotive coverage in 2009. He has been a student at Bob Bondurant’s School of High Performance Driving and holds a Bachelor of Science degree in technology commerce.