Tire size by vehicle type

Whatever you drive, the right size is on the Tire and Loading Information label on the driver's door edge or post, or in the owner's manual. NHTSA says to stick with that size or another size the vehicle maker recommends.^{[1 · Oct 29, 2026]}

We don't publish make-and-model fitment lists. Sizes vary by trim, year and wheel option, so the label on your vehicle is the reliable answer. What we can explain is what kind of size each type of vehicle uses, and what to watch for.

• Cars and minivans

  Car sizes are written as P-metric (P215/55R17) or Euro-metric with no letter (215/55R17).^{[2 · Oct 29, 2026]} Tire Rack says to keep any size change within 3% of the original diameter.^{[3 · Oct 29, 2026]}

• Crossovers and SUVs

  Toyo counts SUVs, minivans and pickups as light trucks. When one comes with P-metric tires, a P-metric tire's load rating is reduced by a factor of 1.10.^{[4 · Oct 29, 2026]}

• Pickups

  Many light trucks come with P-metric tires; more heavy-duty trucks may come with LT tires.^{[4 · Oct 29, 2026]} LT tires use load ranges such as C, D and E.^{[5 · Oct 29, 2026]}

• Dual rear wheel trucks

  LT tires for duals carry two load indexes, such as 104/101: single and dual.^{[6 · Oct 29, 2026]} Toyo doesn't recommend P-metric tires to replace LT duals.^{[4 · Oct 29, 2026]}

• Cargo and passenger vans

  Some use Euro-metric commercial sizes with a C after the rim size, such as 225/75R16C, which have their own load ranges.^{[5 · Oct 29, 2026]}

• Trailers

  Use ST (special trailer) tires only. Carlisle says not to use passenger or light truck tires on trailers, or ST tires on cars or trucks.^{[7 · Oct 29, 2026]} See trailer tire basics.

• Off-road and lifted trucks

  Flotation sizes such as 31x10.5 R15 LT start with the overall diameter in inches.^{[8 · Oct 29, 2026]} Tire Rack writes that pickups and SUVs are usually engineered for up to a 15% oversize tire.^{[3 · Oct 29, 2026]}

• Temporary spares

  Marked T, such as T145/80D18 103M.^{[8 · Oct 29, 2026]} Ram's supplement says not to drive faster than 50 mph (80 km/h) on a compact or temporary spare.^{[8 · Oct 29, 2026]} M is the speed symbol for 81 mph.^{[9 · Oct 29, 2026]}

• All-wheel and four-wheel drive

  Continental recommends replacing all four tires together on these vehicles.^{[10 · Oct 29, 2026]} Tire Rack also recommends matching all four.^{[3 · Oct 29, 2026]}

Swapping P-metric for LT, or the other way

A light truck tire isn't automatically a "heavier duty" upgrade. Size for size, LT tires need more air pressure to carry the same load. Toyo's example: to match a P245/75R16 109 at 35 psi, an LT245/75R16 Load Range C needs 50 psi.^{[4 · Oct 29, 2026]} Details in LT vs P-metric tires.

Replacing two tires instead of four

Tire Rack says if you only replace two, the new pair goes on the rear axle.^{[3 · Oct 29, 2026]}

When it's time to replace

• Tire Rack gives 2/32 in as the legal limit, and NHTSA suggests the penny test to check it.^{[3 · Oct 29, 2026][1 · Oct 29, 2026]}
• Tire Rack suggests considering replacement at 4/32 in if you drive in rain and 5/32 in for snow.^{[3 · Oct 29, 2026]}
• Some vehicle and tire makers recommend replacing tires 6 to 10 years old, whatever the tread depth.^{[1 · Oct 29, 2026]}

Sources: 1. NHTSA, Tires. 2. Tire Industry Association, Reading a tire sidewall. 3. Tire Rack, How do I select the right tires?. 4. Toyo Tires, Technical bulletin TSD-12-011: Replacing tires on light trucks (PDF, Aug 2012). 5. Tire Rack, What are load ranges and ply ratings?. 6. Tire Rack, What is load index?. 7. Carlisle Transportation Products, Trailer tires: tips and best practices (PDF). 8. Ram, 2022 1500 tire and wheel supplement (PDF). 9. Tire Rack, How do I check a tire's speed rating?. 10. Continental Tire, PSIB 06-03: Tire plus-sizing for passenger and light truck vehicles (PDF, 2006). Checked Oct 29, 2026. Size dimensions, revolutions per mile and speedometer figures are our own arithmetic from the size code. Trademarks belong to their owners; figures are restated in our own words and tables, not reproduced.