How Much Weight Can Your Tyres Actually Carry Off-Road?
Most 4WD owners read the load index once, see a big kilogram number, and never think about it again. But off-road, that number is a moving target. Air down for traction and the same tyre carries hundreds of kilograms less. Pile on bar work, drawers, a long-range tank, water and a loaded roof, and you can be running well beyond the tyre’s real capacity without knowing it — until a rear tyre delaminates on a remote track. Here’s how tyre load capacity actually works when the pressure drops and the load climbs.
What does the load index actually mean?
The load index is the number in your tyre size (for example, the 98 in 225/60R16 98T) that sets the tyre’s maximum load. According to Cooper Tires Australia, a higher number means more capacity — and that rating applies only when the tyre is inflated to its maximum pressure. Some common values, per tyre:
| Load index | Max load per tyre (at rated pressure) |
|---|---|
| 95 | 690 kg |
| 98 | 750 kg |
| 100 | 800 kg |
| 105 | 925 kg |
| 110 | 1,060 kg |
| 115 | 1,215 kg |
| 120 | 1,400 kg |
| 125 | 1,650 kg |
For the full passenger-vehicle breakdown, see our tyre load index chart for Australian vehicles. Fit a tyre with too low an index for your vehicle and you’re in trouble — see what happens if you fit the wrong load rating.
Why airing down cuts your load capacity
This is the point most tourers miss. Cooper Tires Australia states plainly that “the load carrying capacity reduces as tyre pressures are reduced.” The load index is quoted at the tyre’s maximum pressure — often 65–80 psi for an LT tyre. Drop to a sand pressure of 16 psi or a corrugation pressure in the high 20s and the tyre supports far less weight, because capacity comes from the air inside doing the work.
One Australian tourer’s experience, documented on ExplorOz, is a cautionary tale: he found a tyre’s quoted maximum applied at 80 psi — “not a realistic off-road pressure” — and that suppliers couldn’t give load ratings at 20, 30 or 40 psi. He’d been running “well beyond their design limits” at sand and gravel pressures, the tyres ran very hot, and he nearly ended up stranded on the Canning Stock Route with two delaminated rear tyres. The lesson: low pressure plus high load plus speed is the formula for a destroyed tyre.
What is load range C, D and E?
Load range is the modern successor to the old “ply rating,” and it tells you how much pressure (and therefore load) an LT tyre is built to handle. Higher load range means a stronger casing rated to a higher maximum pressure:
| Load range | Old ply rating | Typical max pressure | Suits |
|---|---|---|---|
| C | 6-ply | ~50 psi | Lighter 4WDs, lower loads |
| D | 8-ply | ~65 psi | Most touring 4WDs |
| E | 10-ply | ~80 psi | Heavily loaded tourers, towing |
A higher load range carries more at a given pressure and resists heat better under load — which is why heavily built rigs step up to D or E. This is the heart of the LT-construction question, and it pairs with a tougher three-ply sidewall.
How do I know if my tyres can carry my loaded 4WD?
Work it out per corner, loaded. Weigh your fully kitted vehicle (a public weighbridge is ideal), note that the rear is usually heaviest, and compare each axle’s share against the combined capacity of its two tyres — at the pressure you’ll actually run. Because capacity falls with pressure, a tyre that’s fine at 45 psi on the highway may be marginal at 28 psi on corrugations with a full load. If you’ve done a GVM upgrade, your tyre and wheel ratings must support the new legal weight, not the old one. Towing adds another layer — see best tyres for towing a van off-road.
How to protect overloaded, aired-down tyres
If you must run low pressures under load — soft sand, sharp corrugations — the protection is speed. A soft, heavily loaded tyre builds heat fast, and heat is what delaminates casings. Keep speeds low when aired down, monitor tyre temperature on long remote stretches, and reinflate before returning to the highway. Our sand-driving guide and 80/20 tyre guide cover terrain pressures in detail, and a quick tyre deflator helps you set them accurately.
Frequently asked questions
Does my tyre carry less weight when I air down?
Yes. The load index is quoted at the tyre’s maximum pressure. As Cooper Tires Australia notes, capacity reduces as pressure reduces — so a tyre aired down for sand or corrugations carries significantly less than its sidewall rating.
What load range do I need for a touring 4WD?
Most touring 4WDs suit load range D; heavily loaded or towing rigs often step up to load range E. Lighter vehicles with modest loads can run C. Choose based on your loaded weight and pressures.
Can overloading my tyres be dangerous off-road?
Very. Overloading plus low pressure plus speed builds heat that can delaminate a tyre — a real risk on remote tracks far from help. Carry a spare, run correct pressures for your load, and keep speeds down.
How do I find the weight on each tyre?
Weigh the loaded vehicle at a public weighbridge, note the rear is usually heaviest, and divide each axle’s weight between its two tyres. Compare that to the tyres’ capacity at your running pressure.
Is load capacity a legal issue?
It can be. Tyres must meet the placard and any GVM-upgrade requirements, and exceeding ratings can affect insurance. Treat load and GVM compliance as general information and confirm with your state authority and a tyre specialist.
Bottom line: Your tyres carry their sidewall rating only at full pressure — air down and real capacity drops sharply. Match load range to your loaded weight, work out the weight on each corner at your running pressure, keep speeds low when aired down, and confirm load and GVM compliance with a tyre specialist and your state authority.
Load, GVM and compliance figures are general information, not legal or safety advice, and are a 2026 guide. Confirm your vehicle’s limits with your tyre maker’s load tables, a 4WD specialist and your state’s vehicle standards.
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