LT vs P-Metric Tires: Which Is Right for Your Truck?

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LT tires are built for heavier loads and tougher use; P-metric tires are built for passenger cars and light-duty vehicles. If you tow, haul or run a heavy-duty pickup, LT tires are usually the better fit. If your truck is mostly a daily driver with a light load, P-metric can be a reasonable and more comfortable choice. This guide explains the differences so you can decide.

What the letters mean

A tire size such as LT275/65R18 starts with LT, meaning light truck. A size such as P275/65R18 starts with P, meaning passenger. The rest of the numbers read the same way: section width in millimeters, aspect ratio, R for radial construction, and wheel diameter in inches.

Construction and load range

LT tires use a heavier internal construction than P-metric tires of the same size. Their strength is described by a load range letter. Load range C corresponds to a 6-ply rating, D to 8-ply and E to 10-ply. Modern tires do not literally contain that many plies; the ply rating is a way of describing strength. Higher load ranges carry more weight but run at higher inflation pressures.

Inflation pressure

LT tires are designed to run at higher pressures than P-metric tires so they can carry their rated load. Always use the pressure that matches the load you are carrying, using the tire maker’s load and inflation table and the placard on your truck’s door jamb as a starting point.

Towing and hauling

Tire industry guidance reduces the load capacity of P-metric tires by about 9 percent when they are used on pickups and vans, because of the heavier duty cycle. LT tires do not take that reduction. For a truck that regularly tows a trailer or carries a camper, LT tires with an adequate load range give more margin.

Ride, noise and cost

The stronger build of an LT tire often rides firmer and can be louder than a P-metric tire, particularly when the truck is unloaded. LT tires also tend to cost more. A truck that is rarely loaded may be happier on P-metric tires if the manufacturer offers them as an original fitment.

Which should you choose?

• Choose LT if you tow, carry heavy payloads, drive a one-ton or dual-rear-wheel truck, or drive on rough roads.
• Consider P-metric if the truck is a light-duty half-ton used mostly for commuting and the original tires were P-metric.
• Stay with what the maker specifies for load index and speed rating. Never go below the original load index.

What a load index number means in pounds

Every tire carries a load index. For example, a load index of 120 corresponds to 3,086 pounds per tire at the tire’s maximum pressure, and each step up adds more. Multiply the single-tire figure by four to find the most weight a set can carry, then compare that with your truck’s gross vehicle weight rating, which is printed on the door-jamb placard. A set of tires should always be able to carry more than the truck’s rated load.

Tread type is a separate choice

Both LT and P-metric tires come in different tread styles. Highway-terrain tires favor quiet and long wear, all-terrain tires balance on-road manners with grip on dirt and light snow, and mud-terrain tires use aggressive blocks for loose surfaces and are typically louder on pavement. Pick the tread for how you drive and the load range for what you carry. They are independent decisions.

Keep the set matched

• Use the same size, brand and model on all four wheels where possible. Mismatched tires on a four-wheel-drive truck can strain the drivetrain.
• Rotate on the schedule your tire maker recommends. Intervals of 5,000 to 8,000 miles are common.
• Check pressure when the tires are cold, and again when your load changes.

Speedometer and size changes

A taller tire than the original covers more ground per revolution, so the speedometer will read lower than your true speed. If you plan to change tire size, check the overall diameter against the original and expect the speedometer, and sometimes gearing and braking feel, to change.

Heavy-duty trucks are almost always fitted with LT tires from the factory, and replacing them with the same type is the safe default. You can browse current light truck tires and compare sizes and prices. To make sure a tire matches your wheel, read how to read a tire sidewall, and see how to choose 8-lug wheels when you are replacing both.