Will They Fit?
Swapping wheels or upsizing tires? Instantly see how a new tire size compares to your current setup. Check overall diameter, sidewall height, speedometer error, and clearance changes. No guesswork—just precise numbers and a visual side-by-side.
Current Tire
New Tire
Diameter
Sidewall
Speedometer Error
Clearance Change
Understanding Tire Sizes
A metric tire size like 225/45R17 breaks down into three numbers: 225 is the section width in millimeters, 45 is the aspect ratio (sidewall height as a percentage of width), and 17 is the rim diameter in inches. Changing any of these affects overall diameter, which directly impacts your speedometer, gearing, and wheel well clearance.
For off-road builds, a taller tire increases ground clearance and can correct speedometer under-reading, but may require a lift kit. For street tuners, a lower profile tire improves handling response but gives a harsher ride and more risk of rim damage. Always aim to keep overall diameter within 3% of stock to avoid ABS and traction control issues.
Use this tool to compare any two sizes instantly. The visual slider lets you see the difference in diameter; the calculated numbers give you exact speedometer error and clearance change so you can make an informed decision.
Fitment Tips
- Plus Sizing: When increasing rim diameter, decrease aspect ratio to maintain similar overall diameter. Example: 225/45R17 → 225/40R18.
- Wide Tires: A wider tire on the same rim may bulge, affecting actual section width and clearance. Check manufacturer specs for measured rim width.
- Load Index: Ensure the new tire meets or exceeds the vehicle's load rating. This is often overlooked but critical for safety.
- TPMS: Aftermarket wheels may require different TPMS sensors or programming. Don't forget this when budgeting.