Truck Tire Buying Guide: Load Ratings, Tread Types, and What Actually Matters

Truck tires get chosen emotionally more than any other tire category. Aggressive tread looks right on a pickup, so aggressive tread gets bought, and then the owner spends four years listening to road noise and buying fuel to haul a tread pattern they use twice a year.

Meanwhile the number that actually matters, load capacity, gets skipped entirely. This guide fixes both in order: get the load right, then choose the tread.

First, know which class of truck you are shoeing

Category	Typical vehicles	Tire type
Light duty	Half-ton pickups, full-size SUVs, vans	P-metric or LT, load range C or D
Heavy half to three-quarter ton	Three-quarter ton pickups, work vans, tow rigs	LT, load range D or E
One ton and above	Dually pickups, chassis cabs, service trucks	LT, load range E or F
Medium duty commercial	Box trucks, dump trucks, buses	Commercial tires by axle position
Heavy duty commercial	Highway tractors and trailers	Steer, drive, and trailer position tires

The dividing line that matters most for retail buyers is between P-metric and LT.

P-metric vs LT vs flotation sizing

Three sizing systems appear on trucks, and they are not interchangeable.

• P-metric (for example P265/70R17) is a passenger-car system. Many half-ton trucks and SUVs leave the factory on P-metric tires because they ride better and cost less. Important detail: when a P-metric tire is used on a truck, van, or SUV, its rated load capacity must be reduced by roughly ten percent to account for the different loading these vehicles impose. If you tow or haul near capacity, that reduction matters.
• LT (for example LT265/70R17) is built for light trucks: heavier construction, more plies, stiffer sidewalls, and higher inflation pressures. Stronger and more puncture resistant, but heavier, firmer riding, and usually thirstier.
• Flotation (for example 35x12.50R17LT) states overall diameter in inches first. Common on lifted trucks and oversized fitments.

Do not downgrade from LT to P-metric to save money on a truck that works. You can move the other way, from P-metric to LT, if you tow or carry weight, but expect a firmer ride and a small fuel penalty.

Load range and load index, the two numbers to get right

Load range is a letter that describes how much air pressure the tire is built to hold, which is what determines how much weight it can carry. The old term was ply rating, and although modern tires do not literally contain that many plies, the equivalence is still used:

Load range	Equivalent ply rating	Typical application
C	6	Light half-ton use, minivans, smaller vans
D	8	Half-ton with regular towing, heavier SUVs
E	10	Three-quarter and one-ton pickups, most work trucks
F	12	Heavy one-ton, dually, and commercial service applications

Load index is the numeric code near the end of the size, and it maps to a specific maximum load per tire. On an LT size you will often see two numbers, such as 121/118R: the first is the single-wheel rating and the second is the dual-wheel rating for a dually.

The rule is simple and non-negotiable: meet or exceed the load index and load range on the vehicle’s door jamb placard. Going higher is allowed and sometimes wise. Going lower is never acceptable, regardless of how the tire looks or what it costs. The combined capacity of the tires on an axle must support that axle’s gross axle weight rating.

Load capacity is only realised at the correct inflation pressure. A load range E tire aired to half-ton pressures carries like a much weaker tire and builds destructive heat under load. The placard is the source of truth, and it may list a higher pressure for full-load or towing conditions. See our tire pressure guide.

Tread categories: match the pattern to the actual duty cycle

Tread type	Best for	Noise	Tread life	Fuel	Snow
Highway (H/T)	Pavement, towing, high mileage	Lowest	Longest	Best	Limited unless 3PMSF rated
All-terrain (A/T)	Mixed pavement and gravel, job sites, light off-road	Moderate	Good	Moderate	Good on 3PMSF-rated models
Rugged terrain	Off-road appearance with more on-road civility than a mud tire	Higher	Moderate	Lower	Varies
Mud-terrain (M/T)	Deep mud, rock, genuine off-road work	Highest	Shortest	Worst	Poor on ice, large voids do not bite
Commercial by position	Steer, drive, or trailer axle on medium and heavy duty	Varies	Position specific	Rib patterns best	Drive lugs best

Two things surprise people here. First, mud-terrain tires are generally worse in snow and especially on ice than a good all-terrain, because the huge voids that clear mud do not provide the biting edges that grip packed snow. Second, a modern all-terrain with the three-peak mountain snowflake symbol handles the vast majority of what an Ontario truck sees, including unmaintained rural roads and job-site gravel.

Be honest about the duty cycle. If the truck spends ninety percent of its life on the 401 and ten percent on gravel, a highway or all-terrain tire will be quieter, last longer, cost less to run, and perform better in the conditions you are actually in.

Winter, and what M+S really means

Most all-terrain tires carry an M+S marking, but M+S is a tread-geometry designation that a manufacturer can self-apply. It is not a performance test.

The three-peak mountain snowflake (3PMSF) symbol means the tire passed a standardised snow traction test. For Ontario winters, that symbol is the one to look for, and it is what insurers reference for the winter tire discount that Ontario private passenger auto insurers have been required to offer since January 2016.

For a heavy truck that tows through winter, a dedicated winter tire in the correct load range still out-performs a 3PMSF all-terrain on ice by a clear margin. It comes down to how the truck earns its living. Our seasonal changeover and winter tire packages pages cover the two-set approach.

Going bigger: what changes besides the look

Oversizing is common on trucks, and there are real consequences worth planning for.

• Speedometer and odometer error. A larger overall diameter makes the vehicle read slower than it is travelling, and it under-counts distance, which quietly stretches your maintenance intervals. Many trucks can be recalibrated.
• Effective gearing. Bigger tires raise the effective final drive ratio, which softens acceleration and hurts towing performance, sometimes enough to justify a gear change.
• Braking and load. Heavier tires and wheels add unsprung and rotating mass, which lengthens stopping distances.
• Clearance and rubbing. Width, offset, and backspacing all decide whether a tire clears at full lock and full suspension compression. This is where a wheel visualizer and a fitment check save an expensive mistake.
• Load capacity. A bigger tire is not automatically a stronger tire. Verify the load index on the new size.

If you are lifting the truck, sort the wheel and tire package and the fitment together rather than in sequence. See the wheel and tire package builder and our vehicle fitment guide.

“The two mistakes we see on trucks are the same every year. Someone buys mud tires for a truck that never leaves pavement, and someone buys a load range below what the placard calls for because it was cheaper. The first one is just money. The second one is a real safety problem when the trailer is on.”

Faisal Mohammad, Licensed Automotive Mechanic, Limitless Tire

Towing and hauling: pressure is not a set-and-forget number

Trucks are the one category where inflation pressure legitimately changes with the job, and the placard usually tells you so.

• Read the full placard. Many truck placards list a normal cold pressure and a separate, higher pressure for maximum load. Running the light-load pressure with a loaded trailer is the setup that produces heat failures.
• Set pressure cold, before the trip. Not at the halfway point after two hours of highway heat, when the reading will be artificially high.
• Rear axle carries the tongue weight. On a conventional trailer hitch, a meaningful share of trailer weight lands on the rear axle. That is the axle to bring up to the loaded-condition pressure.
• Do not bleed hot tires down. The pressure rise from heat is normal and expected. Removing it leaves you under-inflated when things cool.
• Return to normal pressure when unloaded. Full-load pressure on an empty truck rides badly and wears the tread centre.

Reading wear patterns on a truck

Truck tires are expensive enough that catching a wear pattern early is worth real money. Run your hand across the tread as well as looking at it, because feathering is easier to feel than to see.

What you see	Usual cause	What to do
Both outer edges worn, centre fine	Chronic under-inflation	Correct pressure, check for a slow leak or a failed TPMS sensor
Centre worn, edges fine	Over-inflation, often from running max sidewall pressure	Set to the placard value, not the sidewall maximum
One edge worn	Camber or toe out of specification	Alignment, and inspect suspension components for wear
Feathered or saw-toothed blocks	Toe misalignment	Alignment. Common on trucks after heavy loads or curb strikes
Cupping or scalloped dips	Worn shocks, or a persistent balance problem	Inspect shocks and rebalance. Cupping does not resolve on its own
Flat spot on one tire	Hard braking lock-up, or a tire that sat loaded too long	Inspect. Usually terminal for that tire

On duallies, check the inner tires deliberately. They hide, they are harder to reach with a gauge, and a slow leak on an inner tire routinely goes unnoticed until the outer tire has been overloaded for months.

Cost per kilometre, not price per tire

Truck tires are expensive, and the cheapest set is rarely the cheapest choice. Work the real number: purchase price divided by realistic tread life, plus the fuel difference over that life, plus downtime if the truck earns money.

A quieter highway tire that lasts substantially longer and burns less fuel routinely beats a cheaper aggressive tire on total cost, before you account for the noise you live with every day. For commercial operators, tire cost per kilometre is a line item worth tracking by axle position.

Whatever you choose, protect the investment: correct pressure, regular rotation, and alignment after any significant suspension work or pothole hit. Heavy trucks punish alignment errors faster than cars do, and irregular wear on an expensive LT set is money burning.

How to place the order

1. Read the door jamb placard: size, load index, load range, and cold inflation pressure, including any towing or full-load pressure.
2. Decide the duty cycle honestly, in percentages of pavement, gravel, and off-road.
3. Pick the tread category that matches, then shortlist by 3PMSF if it is a year-round set.
4. Confirm the load index meets or exceeds the placard, and check the dual rating if the truck is a dually.
5. Confirm clearance if you are changing size.
6. Book installation with proper torque to spec and TPMS handled.

You can filter by exact size when you shop tires online with Canada-wide shipping, or bring the truck to any of our five GTA locations and we will read the placard with you before anything is ordered.

Related reading: how to read your tire size, seasonal tire storage, and tire rotation patterns.