Tire Service Tools
Thinking about a different wheel or tire size? Our tire size calculator compares your current tire size against a proposed tire size so you can see the change in overall diameter, sidewall height, tire width, and estimated speedometer accuracy before you buy. Whether you’re checking a plus-size upgrade or a like-for-like tire replacement, this tire diameter calculator gives you the numbers our technicians actually look at.
Original
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New
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| Measurement | Difference |
|---|---|
| Diameter difference | — |
| Diameter % difference | — |
| Sidewall height difference | — |
| Tire width difference | — |
| Speedometer impact | — |
This calculator provides estimates for tire-size comparison purposes only. Actual vehicle compatibility depends on the vehicle, wheel specifications, suspension clearance, load requirements, manufacturer recommendations, and other factors. Always verify the correct tire size and fitment for your vehicle before purchasing or installing tires.
225 is the tire’s width in millimeters, 55 is the aspect ratio (sidewall height as a percentage of width), R means radial construction, and 17 is the wheel diameter in inches that the tire is built to fit.
Enter your current tire size and the size you’re considering into this tire size comparison tool. It calculates the overall diameter, sidewall height, and width for both so you can see exactly how they differ.
Most tire professionals suggest keeping overall diameter change within about 3%. Beyond that, speedometer and odometer accuracy can drift noticeably, and it may also affect ABS and traction control calibration.
Yes. A wider tire generally increases contact patch and can improve grip, but it may also change steering feel, clearance, and rolling resistance. Fender and suspension clearance should always be checked.
Often, within limits. Overall diameter, load rating, and clearance all need to work with your specific vehicle. This calculator shows the size difference, but a technician should confirm fitment for your car.
Larger, heavier, or wider tires typically increase rolling resistance, which can reduce fuel economy. A taller overall diameter can also change effective gearing, which affects how hard the engine works at speed.
A taller sidewall generally absorbs bumps more and rides softer, while a shorter sidewall (common with larger wheels) tends to ride firmer but can improve steering response.
Yes, if the new tire’s overall diameter differs from the original. A larger diameter tends to make your speedometer read slower than your actual speed; a smaller diameter tends to make it read faster.
Check the tire placard inside the driver’s door jamb, the owner’s manual, or the sidewall of your current tires. These list the manufacturer-recommended size for your vehicle.
Yes. A qualified technician can confirm clearance, load rating, and compatibility with your vehicle’s suspension and electronics before you commit to a non-standard tire size.