Speed rating chart
| Symbol | Max speed (mph) | Max speed (km/h) |
|---|---|---|
| N | 87 | 140 |
| P | 93 | 150 |
| Q | 99 | 160 |
| R | 106 | 170 |
| S | 112 | 180 |
| T | 118 | 190 |
| H | 130 | 210 |
| V | 149 | 240 |
| W | 168 | 270 |
| Y | 186 | 300 |
| (Y) | over 186 | over 300 |
Figures are the standardised, rounded mph/km/h pairs the tyre industry publishes for each symbol, not a raw unit conversion. You'll also see ZR on some older performance tyres: it's a pre-1991 marking for anything over 149mph (240km/h), usually printed alongside a W or Y speed rating that gives the actual limit.
Load index chart
| Load index | Max load per tyre (kg) |
|---|---|
| 82 | 475 |
| 84 | 500 |
| 87 | 545 |
| 88 | 560 |
| 91 | 615 |
| 94 | 670 |
| 95 | 690 |
| 98 | 750 |
| 100 | 800 |
| 104 | 900 |
This covers the load index range typical of ordinary cars, small SUVs and light vans. Vans, 4x4s and heavier saloons commonly sit toward the top of this range or above it; always match or exceed the minimum your manufacturer specifies, never just copy the figure off the tyre you're removing.
How to Read a Sidewall Marking
Look at the end of a size code such as 195/65 R15 91V and you'll find two ratings stacked together, easy to mix up because nothing separates them. 91 is the load index: match it against the chart above and it means 615kg is the most this single tyre is rated to carry. V is the speed rating: from the same chart, V tops out at 149mph (240km/h). Neither number is a suggestion, both are hard ceilings the tyre is certified against, not figures to aim for.
Why the Load Index Number Matters
Multiply the per-tyre figure by four (or five, counting the spare) to sanity-check against your vehicle's gross weight, but the figure that actually governs the fitment comes from the manufacturer: they've already worked out the minimum load index each corner needs when fully loaded, and specified it for that exact vehicle. This matters most on vehicles that regularly carry weight near their limit: vans, estate cars packed for a trip, anything towing a laden trailer. A tyre under-rated for the load can overheat and fail well before it looks worn. Fitting a higher load index than specified is generally fine; fitting a lower one is not.
Why the Speed Rating Matters, and the Insurance Angle
The speed rating is a heat and structural limit, not just a top-speed figure, a tyre rated below its limit is more prone to heat buildup and rapid degradation even well under that maximum speed, particularly under load or in hot weather. Fitting a tyre with a lower speed rating than the vehicle manufacturer specifies can affect your insurance: some policies treat it as a modification that needs declaring, and a claim could in theory be contested if the fitted tyres don't meet the handbook's minimum rating. This isn't legal advice, check your policy wording and, if in doubt, ask your insurer directly before fitting anything below the specified rating.
Checking Fitment Alongside Size
Speed rating and load index are only part of the picture. Swapping to a different overall tyre size is a separate decision with its own effects on diameter and speedometer accuracy, worth checking on the tyre size comparator before you commit to anything. Inflation pressure is separate again, and isn't linked to either rating: the tyre pressure converter covers psi, bar and kPa if you need to cross-check a gauge reading.
Frequently Asked Questions
Can I fit a tyre with a higher speed rating than my car needs? Yes, that's always allowed and common on performance trims. A higher-rated tyre simply has more margin than the manufacturer's minimum.
Do all four tyres need to match? They should match the manufacturer's minimum load index and speed rating at every corner. Mismatched ratings front-to-rear are generally discouraged and can cause handling imbalance.
Where do I find my car's required rating? It's specified by the manufacturer for your exact vehicle, alongside the recommended tyre size, in the same place you'd look up pressure. It's set for the car, not guessed from whatever tyre happens to be on it now.
Does a lower load index ever make sense? Only if the manufacturer explicitly allows a lighter-duty tyre for a specific spec, which is rare. As a default, match or exceed the specified figure.