Compare tire sizes
Current diameter–
New diameter–
Diameter change–
Current revs/mile–
New revs/mile–
Actual speed–
Nominal sidewall dimensions often differ from a tire’s mounted, loaded diameter. Use manufacturer specifications for calibration work.
How the conversion works
For a size such as 315/70R17, 315 is section width in millimeters, 70 is sidewall height as a percentage of width, and 17 is wheel diameter in inches. Overall nominal diameter equals two sidewalls plus the wheel.
Why tire dimensions became central to Jeep builds
Larger tires connect styling, ground clearance, gearing, braking, steering, suspension travel, axle strength, and speedometer calibration. Follow that systems story through the evolution of Jeep suspension and Dana and Jeep axle history.