Tire Size Decoder
Tire size FAQ
What do the numbers on a tire mean?
A code like 225/45R17 94V reads: 225 = section width in mm, 45 = aspect ratio (sidewall is 45% of the width), R = radial construction, 17 = wheel diameter in inches, 94 = load index, V = speed rating. Enter yours above for the full breakdown.
What is the load index?
The load index is a code for the maximum weight one tire can carry — e.g. 94 ≈ 670 kg. Always fit tires that meet or exceed the load index on your vehicle’s door-jamb placard.
What is the speed rating?
The speed-rating letter is the maximum sustained speed the tire is designed for — e.g. H = 210 km/h, V = 240 km/h, W = 270 km/h. Don’t fit a lower speed rating than your vehicle specifies.
How do I find my tire size?
It’s printed on the tire sidewall, and usually also on the driver’s door-jamb placard, in the fuel-filler flap, or in your owner’s manual.
Can I change to a different tire size?
You can fit a different size if the overall diameter stays close (within ~3%) to keep the speedometer accurate and avoid clearance/load problems. Use the overall-diameter figure above to compare sizes, and confirm load index and speed rating still meet the placard.