Tire Speed Rating Comparator
Compare the speed rating of a replacement tire with the original. See the gap in km/h and mph and whether the new tire meets the spec.
Compare specified speed categories.
Tire Speed Rating Comparator: Tire Size Inputs
Compare two tire sizes here. Use the formulas and reference tables below for this tool's specific calculation.
How Tire Speed Rating Comparator Works?
The Tire Speed Rating Comparator works by decoding both speed rating letters into maximum speeds and comparing the 2 values. The tool uses 3 steps.
Enter the original rating
Type the rating from the placard, for example V.
Enter the replacement rating
Type the replacement rating, for example H.
Read the result
The comparator returns −30 km/h (−19 mph) and marks the replacement as lower than original.
Tire Speed Rating Comparator Formula
The Tire Speed Rating Comparator formula is ΔV = V(SR_rep) − V(SR_orig), with a pass when ΔV ≥ 0.
ΔV = V(SR_rep) − V(SR_orig)V(SR_rep) ≥ V(SR_orig)V(SR_winter) ≥ V_vehicle-limit (sticker required in some regions)- SR
- Speed rating letter
- V(SR)
- Maximum speed of the rating (km/h)
Worked example
Replacing a W-rated tire (270 km/h, 168 mph) with a Y-rated tire (300 km/h, 186 mph) adds 30 km/h (18 mph) of rated speed and passes.
Tire Speed Rating Comparator Conversion Table
The Tire Speed Rating Comparator conversion table compares 7 original-to-replacement speed rating changes.
| Rating change | km/h | mph | Gap | Result |
|---|---|---|---|---|
| H → V | 210 → 240 km/h | 130 → 149 mph | +30 km/h (+19 mph) | Meets or exceeds |
| V → H | 240 → 210 km/h | 149 → 130 mph | -30 km/h (-19 mph) | Lower than original |
| V → W | 240 → 270 km/h | 149 → 168 mph | +30 km/h (+19 mph) | Meets or exceeds |
| T → H | 190 → 210 km/h | 118 → 130 mph | +20 km/h (+12 mph) | Meets or exceeds |
| W → Y | 270 → 300 km/h | 168 → 186 mph | +30 km/h (+18 mph) | Meets or exceeds |
| S → T | 180 → 190 km/h | 112 → 118 mph | +10 km/h (+6 mph) | Meets or exceeds |
| Y → V | 300 → 240 km/h | 186 → 149 mph | -60 km/h (-37 mph) | Lower than original |
What is Tire Speed Rating Comparator?
A Tire Speed Rating Comparator is a tool that checks whether a replacement tire's speed rating matches or exceeds the original. Vehicle makers specify a minimum rating for each model.
Mixing ratings on one vehicle lowers the safe speed to the lowest rating fitted. Many tire makers advise against mixing ratings across axles.
Winter tires are the common exception. Several European countries allow a lower winter rating when a speed reminder sticker sits in the driver's view.
What are the uses of Tire Speed Rating Comparator?
There are 4 main uses of the Tire Speed Rating Comparator, including quote verification and winter tire checks.
Quote verification
Catch a lower-rated tire in a shop quote.
Winter tire checks
Confirm a lower winter rating is allowed and label the dash.
Mixed set checks
Find the lowest rating on a mixed set.
Performance upgrades
Confirm higher ratings for track use.
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