Two truck tires can share the same size, fit the same rim and look almost identical — and still be built for completely different jobs. The letter in front of the size tells you which: P for P-metric (passenger) or LT for light truck. Getting LT vs P tires right affects how much your truck can safely carry, how it rides and how long the tires last. Here is how to choose.
What P and LT mean on a tire size
Look at a size like P275/60R20 or LT275/55R20. The leading letters tell you the construction standard:
- P-metric tires are built for passenger vehicles, SUVs and most half-ton pickups. They prioritise ride comfort and a quieter, smoother drive.
- LT (light truck) tires are built with stronger construction to carry heavier loads at higher pressures — for towing, hauling and three-quarter and one-ton trucks.
Some truck sizes have no letter at all, and flotation sizes such as 33x12.50R17LT put the LT at the end. Our tire size chart explains how to read each part of the size.
Tire load index and speed rating
After the size comes the service description — for example 115S or 120/117S. The number is the load index: a code for how much weight each tire can carry at its maximum pressure. The letter is the speed rating, the maximum sustained speed the tire is rated for.
LT tires often show two load numbers, like 120/117. The first is the load per tire in single use; the second is for dual-rear-wheel use, where two tires share the load. When you replace tires, the load index and speed rating should meet or exceed what is on your door-jamb placard.
Ply rating and load range
LT tires are also rated by load range — C, D, E and so on — often described as a ply rating (Load Range E is commonly called "10-ply"). A higher load range means a stronger casing that runs at higher pressure to carry more weight. It also means a firmer ride when the truck is empty.
Which does your truck need?
Half-ton pickups and SUVs
Most half-tons leave the factory on P-metric tires, and for daily driving that is usually right. If you tow a heavy trailer, carry loads regularly or drive a lot of gravel, an LT tire can be worth the firmer ride. Our Haida HD868 is a P-metric highway tire for full-size pickups — quieter than an LT equivalent — and the HD837 is a highway tire for half-tons, SUVs and crossovers.
Three-quarter and one-ton trucks
Heavy-duty pickups should stay on LT tires with the load rating the placard calls for. The Haida HD829 is 10-ply LT construction with dual-marked load ratings, built for HD pickups that work.
Lifted trucks and off-road builds
Bigger tires on a lifted truck are usually LT or flotation sizes. The Haida HD878 all-terrain comes in LT and flotation sizes, Load Range E, and the HD869 mud-terrain covers 33 to 37 inch for lifted builds.
Vans and work vehicles
Cargo vans often use C-type commercial tires — a similar idea to LT. Our Haida HD737 is C-rated commercial construction for vans and work vehicles.
Common mistakes to avoid
- Going below the placard. Never fit a tire with a lower load index than your truck requires.
- Copying the old pressure. LT and P tires run at different pressures. Set them to the placard or the tire's load requirement, not to what the old tires had.
- Ignoring the rim. Bigger tires and new wheels have to fit your truck's bolt pattern, offset and load rating. If you are asking what size rims fit your truck, start with our wheel bolt pattern guide.
Wheels and tires together in Edmonton
If you are changing wheels and tires at the same time, we can check the fitment for your exact truck and fit both in our own bays at 2843 50 Ave NW. Tire installation is $100 for a set of four or $25 a tire, by appointment, and the hardware that goes with a wheel change is fitted free when you buy it here. Browse truck tires, see our wheels, or call (780) 518-1000 with your year, make and model and we will tell you whether P or LT is right.