Tire load range

Falken Tire describes load range as a range of loads a tire can carry at a specified pressure. The separate load index identifies its maximum load capacity in pounds or kilograms.

49 CFR 571.139 (FMVSS No. 139) requires the sidewall to show maximum load and, for LT tires, the load range letter. 49 CFR 571.119 (FMVSS No. 119) also requires a load range letter on tires it covers.

Nitto and Toyo identify C as a 6-ply rating, D as an 8-ply rating, E as a 10-ply rating, and F as a 12-ply rating. The load range chart pairs these letters with their ply-rating equivalents.

Falken Tire explains that a 12-ply rating does not necessarily mean 12 physical layers. 49 CFR 571.139 (FMVSS No. 139) separately requires the actual sidewall and tread ply counts to be marked on the tire.

Not always: Nitto and Toyo size tables include E-rated tires with maximum pressures of 80 psi or 65 psi. Their tables also include C at 35 psi or 50 psi, D at 50 psi or 65 psi, and F at 80 psi.

Toyo lists the Open Country R/T Trail in P-metric 275/65R20 SL at 2,756 lbs maximum load at 44 psi. Its LT275/65R20 E version carries a listed maximum of 3,750 lbs at 80 psi; Toyo lists both at 34.1 in overall diameter.

Toyo also lists the Open Country A/T III in P-metric 265/70R17 SL at 2,679 lbs at 44 psi. The LT265/70R17 E version is listed at 3,195 lbs at 80 psi, with both measuring 31.7 in overall diameter.

These are published maximums, not recommended operating pressures. For inflation pressure, see the tire and loading placard on the driver's door jamb.

LT identifies a light-truck tire; SL means Standard Load for passenger tires. Michelin says XL means Extra Load, with reinforced construction that carries higher loads than standard tires of the same size at higher pressures.

An LT designation alone does not guarantee more capacity: Toyo lists its LT265/70R17 C Open Country A/T III at 2,470 lbs, versus 2,679 lbs for the P-metric SL version. Compare the specific load index and published capacity, not just the prefix.

Michelin says never to use a lower load index than the factory specification and to retain XL when the factory tires are XL. Under 49 CFR 571.110 (FMVSS No. 110), the placard lists the vehicle maker’s recommended cold inflation pressures. See the tire and loading placard on the driver's door jamb.