Load range and ply rating explained
Load capacity is not optional. Tires must carry your vehicle’s weight, passengers, cargo, and—if you tow—the tongue weight safely. Passenger and light-truck tires express that capacity differently; this guide explains the common labels so you can compare apples to apples.
Passenger tires: Standard Load (SL) and Extra Load (XL)
Many P-metric passenger tires are marked Standard Load (SL) or Extra Load (XL). XL tires allow a higher maximum load at a higher inflation pressure than the same size in SL. You will see the load index and speed rating on the sidewall; together they define the tire’s rated capacity.
If your placard or original tire specifies XL, do not downsize to SL without verifying that the replacement meets the required load index.
LT load ranges and ply ratings
Light-truck metric tires often use load range letters. Common mappings you will see referenced: Load Range C with a 6-ply rating equivalent, D with 8-ply, E with 10-ply, and F with 12-ply. The ply number is a strength rating tradition—not always the literal number of physical plies in a modern tire.
Higher load range generally means more carrying capacity at the specified pressure. Work trucks, heavy SUVs, and towing setups frequently need D or E range; some commercial or heavy-duty applications need F.
Why matching capacity matters
Under-rated tires can overheat, wear unevenly, and fail under load. Over-rated tires may ride harsher if inflated incorrectly, but the critical rule is: meet or exceed the manufacturer’s required load for your vehicle configuration.
Check the driver’s door jamb placard and owner’s manual for the recommended size, load index, and speed rating. Compare those to the sidewall of any tire you plan to buy.
Construction: P vs LT
A P-metric tire and an LT tire with similar numbers are not interchangeable by size alone. LT tires are built for heavier loads and different inflation expectations. If your truck came with LT sizes, stay in that family unless a qualified installer confirms a passenger alternative is appropriate.
Our light-truck tire category lists LT construction tires in stock when you want to filter by size and brand.
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