Tire Load Index & Speed Rating Chart Explained
Two small codes on every tire sidewall — the load index and speed rating — tell you how much weight a tire can carry and how fast it’s rated to run. For dealers and fleets buying in bulk, reading them correctly prevents under-spec’d, unsafe, or unsellable inventory.
Where to find them
They appear right after the size, e.g. 11R22.5 148/145L — here 148/145 is the load index (single/dual) and L is the speed symbol.
Speed rating chart
| Symbol | Max speed | Symbol | Max speed |
|---|---|---|---|
| L | 75 mph (120 km/h) | S | 112 mph (180 km/h) |
| M | 81 mph (130 km/h) | T | 118 mph (190 km/h) |
| N | 87 mph (140 km/h) | U | 124 mph (200 km/h) |
| P | 94 mph (150 km/h) | H | 130 mph (210 km/h) |
| Q | 100 mph (160 km/h) | V | 149 mph (240 km/h) |
| R | 106 mph (170 km/h) | W | 168 mph (270 km/h) |
Commercial and off-road tires usually use the lower symbols (L–R); passenger/UHP tires use H and above.
How load index works
The load index is a coded number, not pounds. Each number maps to a max load — for example, load index 100 = 800 kg (1,764 lb) per tire. The scale rises with the number, so a higher index carries more. Truck tires often show two numbers (single/dual axle use). Look up the exact pounds for any index on a standard load-index table.
- Match to axle load. Combined tire capacity must exceed the loaded axle weight, with margin.
- Never downgrade below the vehicle/equipment requirement.
- Dual fitment uses the second (lower) number per tire.
Need help spec’ing bulk tires by load and application? Open a wholesale account or request a quote →
Frequently asked questions
What does 148/145L mean on a truck tire?
148 = single-tire load index, 145 = dual load index, L = speed symbol (75 mph). Look up the index numbers for exact load in lbs.
Is a higher load index always better?
It carries more weight, but always match the vehicle/equipment requirement and correct size — don’t over- or under-spec.
Why do commercial tires have low speed ratings?
They’re built for load and durability at lower sustained speeds, so symbols like L–R are normal and appropriate.