Truck Tire Size Guide: OEM Charts, LT vs P-Metric, Load Ranges & Upgrade Rules
OEM sizes for F-150, Silverado, RAM, Tundra, and Tacoma. Load ranges, LT vs P-metric, biggest tires without a lift, plus-sizing, and towing safety — everything before you buy.
Need your exact stock size?
Use the tire placard first. NHTSA says the Tire and Loading Information Label (driver's door edge or post) or your owner's manual give the correct size.
Tow or haul often?
Michelin says a tire's load rating must always meet or exceed the vehicle manufacturer's value. Do not go below the load capacity on the placard.
Going to a different size?
Michelin says to replace tires with the same size designation, or approved options, recommended by the vehicle manufacturer. Check the diameter difference with the calculator first.
Stepping up to 35s?
A larger diameter makes the speedometer read lower than actual speed (calculated) and lowers the effective axle ratio (calculated). Ask the vehicle manufacturer whether the size is approved.
Confused by LT275/70R18?
LT = light truck, 275 = width in mm, 70 = sidewall ratio, R = radial, 18 = wheel diameter in inches.
Use the calculator for the exact math
Compare stock vs upgraded truck tire sizes in seconds
See diameter, sidewall, circumference, revolutions per mile, and speedometer difference before buying.
How to read a truck tire size
The sidewall tells you the service type (P or LT), width, sidewall height, construction, wheel diameter, load index and speed rating.
Check the size, load index and speed rating against your tire placard.
LTService type
Light Truck construction. Built for higher load and inflation than passenger tires.
275Section width
The tire is about 275 mm wide at its widest point.
70Aspect ratio
Sidewall height is 70% of the 275 mm width.
RConstruction
Radial construction, standard on modern truck tires.
18Wheel diameter
Fits an 18-inch wheel only.
125/122Load index
Single / dual load index on some LT tires. Higher number = more carrying capacity.
SSpeed rating
Maximum speed capability for the tire when properly inflated and loaded.
ELoad range
Load range letter. Continental and Carlisle pair load range E with a 10-ply rating; maximum pressure and load depend on the tire size and maker.
Some trucks come from the factory with P-metric tires and some with LT tires. Your placard says which.
LT vs P-metric truck tires
Follow the service type, load index and load range on your placard. Michelin says a tire\'s load rating must always meet or exceed the vehicle manufacturer\'s value.
| Factor | P-metric | LT | Usually Better |
|---|---|---|---|
| Prefix on the size | P, for passenger car tires (for example P265/70R17). | LT, for light truck tires (for example LT275/70R18). | Follow the placard |
| Load rating | Marked with a load index in the service description (for example 115T). | Marked with a load index and a load range letter such as E (10-ply rating). | Follow the placard |
| Replacement rule | Michelin: load rating must meet or exceed the vehicle manufacturer's value. | Same. Ford's manual: tires and wheels must be the same size, load index and speed rating as those originally fitted. | Follow the placard |
We have no official source recommending LT over P-metric tires, or the reverse, for a given use. Match the placard, and ask the vehicle manufacturer before changing service type.
Truck tire load range chart
Bridgestone says there is no industry-wide definition of ply rating: truck tires are marked with a ply rating and an equivalent load range to identify the load and inflation limits of that tire. The maximum load and pressure depend on the tire size and maker, so read them from the sidewall or the maker's data book.
| Load Range | Ply Rating |
|---|---|
| C | 6-ply rating |
| D | 8-ply rating |
| E | 10-ply rating |
| F | 12-ply rating |
Never choose a replacement tire with less load capacity than the original equipment requirement. Diameter fitment is irrelevant if the tire cannot safely carry the truck’s axle load.
Ford F-150 stock tire sizes
Sizes below are named in Ford's F-150 owner's manuals and the 2026 specifications, so the F-150 has no single tire size.
| Trim / Package | OEM Size | Notes |
|---|---|---|
| XL, XLT 4x2 | 245/70R17 | Ford manuals. |
| XL 4x4 | 265/70R17 | Ford manuals. |
| STX, Lariat 4x2 | 265/60R18 | Ford manuals. |
| STX, XLT, Lariat 4x4 | 275/65R18 | Ford manuals. |
| Tremor | 275/70R18 | Ford manuals. |
| King Ranch, Platinum; STX, Lariat optional | 275/60R20 | Ford manuals. |
| STX Lobo, King Ranch, Platinum optional | 275/50R22 | Ford manuals. |
| Raptor | LT315/70R17 or 37x12.50R17 (Raptor 37 Package) | Ford 2026 F-150 specifications. |
Silverado 1500 and Sierra 1500 stock sizes
The Chevrolet Silverado 1500 and GMC Sierra 1500 owner's manuals name these sizes in their tire chain warnings. They do not list sizes by trim, so use your tire placard for your truck.
| Trim / Package | OEM size | Notes |
|---|---|---|
| Silverado 1500, 2025 manual | 275/50R22, 275/60R20, LT265/60R20, LT265/70R17, LT275/65R18, LT275/70R18 | Named in the manual's tire chain warning: do not use tire chains on these sizes. No trim-by-trim list; use your placard. |
| Sierra 1500, 2025 manual | 275/50R22, 275/60R20, LT265/60R20, LT265/70R17, LT275/65R18, LT275/70R18 | Same sizes and warning as the Silverado manual. |
| Sierra 1500, 2021 and 2022 manuals | 275/50R22, 275/60R20, LT265/60R20, LT265/70R17, LT275/65R18 | Do not use tire chains on these sizes. |
| Sierra 1500, 2019 manual | LT265/70R17, LT275/65R18, 275/60R20, 275/50R22 | Do not use tire chains. The manual says chains may go on the rear axle only for 265/70R17 or 265/65R18, and on the front and rear axle for 255/70R17. It classes 275/60R20 and 275/50R22 as low-profile tires. |
RAM 1500 stock tire sizes
Sizes below are named in RAM's owner's manuals for the 1500, 2500 and 3500.
| Trim / Package | OEM size | Notes |
|---|---|---|
| RAM 1500: Tradesman, HFE, Big Horn / Lone Star, Laramie (18") | 275/65R18 | RAM 2020–2025 manuals. |
| RAM 1500: Tradesman, Big Horn / Lone Star, Laramie, Longhorn, Sport, Limited (20") | 275/55R20 | RAM 2020–2025 manuals. |
| RAM 2500 Tradesman (17") | LT245/70R17E | RAM 2025 manual. |
| RAM 2500 Tradesman 4x4, Power Wagon (17") | LT285/70R17D | RAM 2025 manual. |
| RAM 2500 / 3500 single rear wheel (18") | LT275/70R18E | RAM 2025 manual. |
| RAM 2500 / 3500 single rear wheel (20") | LT285/60R20E | RAM 2025 manual. |
| RAM 3500 dual rear wheel (17") | LT235/80R17E | RAM 2025 manual. |
Toyota Tundra and Tacoma stock sizes
Sizes below are from Section 8-1 of Toyota's 2025 Tundra and Tacoma owner's manuals.
| Model / Package | OEM size | Notes |
|---|---|---|
| 2025 Tundra (18") | 245/75R18 112T or 265/70R18 116T | Toyota 2025 Tundra owner's manual, Section 8-1. |
| 2025 Tundra (20") | 265/60R20 112H | Toyota 2025 Tundra owner's manual, Section 8-1. |
| 2025 Tacoma (17") | 245/70R17 110T or 265/70R17 115T | Toyota 2025 Tacoma owner's manual, Section 8-1. |
| 2025 Tacoma (18") | 265/65R18 114T | Toyota 2025 Tacoma owner's manual, Section 8-1. |
Biggest tires without a lift
We have no official source for how large a tire fits without a lift. Manufacturers say to use approved sizes (Ford: same size, load index and speed rating as originally fitted), so the figures below are what the sources say and how to calculate the change. An inch size can be written in metric with the flotation to metric chart, and the ply rating and load range guide explains the letters on the sidewall.
| Truck Type | Typical Stock Diameter | Reasonable No-Lift Ceiling | Watch For |
|---|---|---|---|
| Any truck: manufacturer approval | Placard size | Same size designation or an approved option (Michelin) | Ford's manuals say wheels and tires must be the same size, load index and speed rating as those originally fitted. |
| All-wheel-drive and four-wheel-drive trucks | All four tires the same size | Outside circumferences within 1 inch (2.5 cm) of each other | Michelin gives this when the owner's manual has no instructions on mixing tires; follow your manual first. |
| Diameter change | Compare overall diameters | Calculate the percentage difference | Continental advises keeping rolling circumference within 3% of the original; this is not a manufacturer specification. Use the truck tire size calculator. |
Compare the actual overall diameters with the truck tire size calculator and ask the vehicle manufacturer or a dealer whether the size is approved.
Truck plus-sizing examples
Plus-sizing means increasing wheel diameter while keeping the tire's overall diameter close to stock. The examples below use sizes from the manuals and calculated diameters.
| Starting Size | +1 Wheel Step | +2 Wheel Step | Why It Works |
|---|---|---|---|
| 265/70R17 | 275/65R18 | 275/60R20 | Calculated: 31.6 in to 32.1 in (+1.5%), then 33.0 in (+2.9% from the 18-inch size). All three sizes appear in Ford F-150 manuals. |
| 275/65R18 | 275/60R20 | 275/50R22 | Calculated: 32.1 in, 33.0 in (+2.9%), 32.8 in (-0.5% from the 20-inch size). All three appear in Ford F-150 manuals. |
| 245/70R17 | 265/65R18 | — | Calculated: 30.5 in to 31.6 in (+3.5%). Both sizes appear in the Toyota Tacoma 2025 manual; this is a larger change. |
| 265/70R18 | 265/60R20 | — | Calculated: 32.6 in to 32.5 in (-0.3%). Both sizes appear in the Toyota Tundra 2025 manual. |
What bigger truck tires actually change
A different tire diameter changes speedometer accuracy and effective gearing (calculated). The speedometer error calculator, the effective gear ratio calculator and the highway RPM calculator each work out one of those effects.
Speedometer error
A taller tire travels farther per wheel rotation, so the speedometer and odometer read low unless recalibrated (calculated).
Effective gearing
Effective axle ratio = axle ratio × (stock diameter ÷ new diameter), so a taller tire lowers the effective ratio (calculated).
Load capacity
Michelin says a tire's load rating must meet or exceed the vehicle manufacturer's value.
Vehicle approval
Ford's manuals say tires and wheels must be the same size, load index and speed rating as those originally fitted. Ask the manufacturer about other sizes.
Common truck tire fitment mistakes
Mistakes to avoid, with what Michelin and the manuals say.
Buying by diameter only
Michelin says to replace tires with the same size designation, or approved options. Check width, load index and speed rating too.
Ignoring load index
Michelin says a tire's load rating must always meet or exceed the vehicle manufacturer's value, and a lower load index than the factory specification should never be fitted.
Skipping the speedometer check
A larger overall diameter makes the speedometer read lower than your actual speed (calculated).
Mixing tire sizes on a four-wheel-drive truck
Michelin says that without instructions in the owner's manual, all four tires must be the same size and within 1 inch of each other in circumference.
Copying another owner's fitment blindly
Your placard and owner's manual give the sizes for your truck.
Before ordering truck tires
Run the stock vs upgrade comparison first
Compare any two truck tire sizes for diameter change, sidewall difference, circumference, and speedometer error.
Sizes in this guide come from the owner's manuals and specifications named in each section. Manufacturers can change wheel packages mid-cycle or by market. The placard on your specific truck is always the final authority.
Truck tire size questions answered from manufacturer, Michelin and NHTSA statements.