LT tire load range chart: C, D, E, 10PR and 119/116

What the load range letter on a light truck tire means, the ply rating and max pressure for B to F, how to read 10PR and a 119/116 single/dual load.

What the load range letter tells you

Load range is the letter on a light truck tire, most often C, D or E, that marks how strong the casing is and how much air it is built to hold at its rated load. Federal rules require every LT tire to print that letter on the sidewall, next to its maximum load. Match the letter. Not the brand, not the tread.

Two truck tires can share one size and still be built for very different work. NHTSA's chief counsel explained it in a 1985 letter: load ranges exist because these tires "may have identical physical dimensions and, therefore, identical size designations, but widely differing load-carrying capabilities." That's why the letter is there at all, and why it deserves a look before the price tag does.

Load range chart: ply rating and max pressure

Each letter lines up with a ply rating and a maximum load pressure, the pressure at which the tire is rated to carry its maximum load. The numbers below are from Tire Rack's light truck chart. Width matters here.

The federal tire pressure monitoring standard, FMVSS 138, prints the same three kPa figures in its Table 1 under "maximum or rated inflation pressure": 350 for load range C, 450 for D, 550 for E. It rounds C to 51 psi where Tire Rack prints 50; 350 ÷ 6.9 is about 50.7, so both are rounding the same number.

Tire Rack adds a warning under its own table. Select LT sizes are built with modified maximum pressures, and you should never exceed the maximum pressure or load shown on the sidewall. So this chart tells you what a letter usually means. The tire in your hands tells you what that tire means.

Where the real maximum lives

The maximum pressure is molded on the sidewall, and it governs over any chart, this one included. For LT tires, FMVSS 139 says that number has to be the pressure that matches the tire's maximum load in the industry tables, and the maker may print up to 10 psi more. Read it off the tire you're holding. Pressure for the road comes from the door placard; NHTSA puts it bluntly: the correct pressure "is what the vehicle manufacturer has listed, NOT what is listed on the tire itself."

Lab test pressures, not what you inflate to

The federal tire standards also carry pressures, and these are the ones that get misquoted. They are what a lab inflates a tire to before running it on a test drum. Never put them in a customer's tire.

The pressure columns come from FMVSS 139, which lists only load ranges C, D and E. The strength column comes from Table II of FMVSS 119, the plunger test that FMVSS 139 also applies to LT tires. The main chart and the FMVSS 139 test tables agree on one pattern: a wide tire with the same letter gets less air. A load range E wider than 295 mm runs its endurance test at 340 kPa, exactly what a narrow D gets.

Deep-tread LT tires

LT tires with 18/32 inch of tread or more fall outside FMVSS 139 and under FMVSS 119 instead. That standard also requires the load range letter on the sidewall, plus the actual number of plies and the cord material.

What 10PR means

"10PR" is a ply rating of 10, and a 10-ply rating is load range E. Tire Rack says LT tires are branded with either their load range ("load range E or LRE") or their ply rating ("10 ply rated"), so the two marks name the same class. The chart above gives the rest of the ladder.

NHTSA describes ply rating as "an older system which performed the same function now served by the load range," with ratings that ran from 2 to 24 and lower numbers meaning less carrying capacity. It is a rating. Tire Rack puts it plainly: today the ply rating doesn't indicate the actual number of plies used in the tire.

The federal marking rules ask for the actual plies separately, as their own line of small print on the sidewall, so a tire can show a ply rating and a real ply count side by side. Don't confuse the two on the tag. A tire with 10PR on the sidewall gets an E.

SL, XL and LT are three different things

Passenger tires don't carry a load range letter. They come in standard load or extra load, and FMVSS 139 defines an extra load tire as one "designed to operate at higher loads and higher inflation pressure than the corresponding standard tire." Michelin's sidewall guide describes XL, HL and Reinforced tires as built to carry higher loads than standard tires of the same size.

The rule also sets the passenger pressure ceilings. A passenger tire's maximum permissible pressure has to be 240, 280, 300, 340 or 350 kPa, and the sidewall prints the psi in parentheses, rounded up to the next whole number. Do the math on the first one: 240 ÷ 6.9 ≈ 34.8, rounded up to 35 psi.

LT is its own class. Michelin describes an LT tire as having "a stiffer carcass and higher load capacity" and warns that putting P-metric tires on a truck that came on LT tires "will leave you short on load capacity." An XL passenger tire is still a passenger tire. Don't swap one in.

Reading 119/116: single and dual load

Some LT tires carry two load numbers split by a slash. Tire Rack explains it this way: the first number is the load index when the tire runs on a single-wheel rear axle, and the second applies when it runs as part of a dual pair. Take LT 119/116. From the load index chart, 119 is 2,998 pounds and 116 is 2,756 pounds per tire.

The dual number is lower on purpose. It builds in reserve in case one tire of the pair fails and its partner has to carry both shares. Do the arithmetic for a dually's rear axle: four tires at 2,756 pounds each is 11,024 pounds of tire capacity, a ceiling for the tires and nothing more. The axle rating on the vehicle still governs. Tires that fall under FMVSS 119 spell the same idea out in words, "Max load single" and "Max load dual," each with its own cold pressure.

The rule nobody at the counter gets to bend

For commercial vehicles, the federal motor carrier rules say it outright: no vehicle "shall be operated with tires that carry a weight greater than that marked on the sidewall of the tire." The same section says no tire may run at a cold pressure "less than that specified for the load being carried." Neither line mentions size. Both are about load.

For everyone else the logic is the same. Buy the size the vehicle came with or one the vehicle maker recommends, which is NHTSA's rule, and keep the letter and the load index at or above what that truck was built around. Higher is fine. Lower comes back as a complaint, or worse.

Used LT tires on your rack

A used LT tire's letter doesn't wear off with the tread. Write it on the tag next to the size, and look at it again when you grade the tire and when you price it, because a customer who tows will ask about the letter first. DuroBay keeps the size, brand, model and DOT on each tire, and the load range letter and the 119/116 pair can go in that tire's notes. If the size itself is the question, start with how to read a tire size.