Ford F-350 Tire Size Guide: OEM, Plus-One & Off-Road Options

You're standing in the Discount Tire parking lot, door sticker in one hand, phone in the other. The counter guy just quoted three different sizes for your 2021 F-350. The window sticker says LT275/65R20. The previous owner slapped 35s on it. The rack near the door has a set of AT4Ws that would look mean but might rub. Which one's right?

This guide gives you the exact factory sizes by year and trim, walks through the plus-one step most owners actually run, and lays out what it takes to fit 35s or 37s without wrecking your CV joints.

Most F-350 Super Duty trucks run LT275/70R18 (XL and XLT with 18-inch wheels) or LT275/65R20 (Lariat and up with the 20-inch package) from the factory. A plus-one step to LT285/65R20 fits stock suspension without rubbing. True 35-inch tires need a 2-inch leveling kit. Always stick with Load Range E (10-ply) on an F-350. Dropping to Load Range D undercuts your GVWR and creates legal liability.

F-350 Factory Tire Sizes by Year and Trim

Ford doesn't put one tire on the F-350. The size shifts with the trim, the wheel package, and whether you ordered single or dual rear wheels. That's why the door jamb sticker is the only spec that matters for your specific truck. Here's how the fleet breaks down.

The base XL and XLT ship on 18-inch steel or aluminum wheels with LT275/70R18. Step up to Lariat, King Ranch, Platinum, or Limited, and you're on the 20-inch package running LT275/65R20. Both sizes are Load Range E (10-ply rating). Ford calls out this rating for every F-350 application. Anything less cuts into the truck's rated payload before you even hook up a trailer.

Dually trucks are different. The rear runs LT225/75R17 to fit inside the dual-wheel spacing without the tires touching. Fronts stay on the wider single sizes.

Here's the year-by-year breakdown for SRW trucks:

Model Year	Trim	Wheel	Factory Tire Size	Load Range
2017-2019	XL / XLT	18"	LT275/70R18	E
2017-2019	Lariat and up	20"	LT275/65R20	E
2020-2022	XL / XLT	18"	LT275/70R18	E
2020-2022	Lariat / King Ranch	20"	LT275/65R20	E
2020-2022	Platinum / Limited	20"	LT275/65R20	E
2023-2025	XL / XLT	18"	LT275/70R18	E
2023-2025	Lariat and up	20"	LT275/65R20	E
2023-2025	Tremor package	18"	LT285/75R18	E

Use this chart to match your VIN year and trim before you order. When in doubt, cross-check against the Ford spec page or your door-jamb sticker.

One quirk worth noting: the 2023+ Tremor package runs LT285/75R18 from the factory. This measures 34.8 inches, so those trucks already come with what most owners try to install aftermarket.

How to Read Your F-350 Tire Sidewall

The sidewall is a spec sheet. Every character means something. On a 1-ton truck, a couple of them matter more than most owners realize.

Take LT275/70R18 121/118R Load Range E. The "LT" tells you it's a Light Truck tire, built with heavier plies than a passenger (P) tire. On an F-350, always LT. Never a P. A P-metric tire won't carry the load.

The 275 is section width in millimeters. The 70 is the aspect ratio (sidewall height as a percentage of width). The R is radial construction, and 18 is the wheel diameter in inches.

That 121/118 is the load index. Load index 121 equals 3,297 lb per tire at max pressure. The R at the end is the speed rating (up to 106 mph).

Load Range E is the piece most guys miss. It's a 10-ply equivalent rating and Ford's minimum for F-350 GVWR. Load Range D (8-ply) exists and costs less, but it caps out below where a loaded F-350 sits. Save the D-rated rubber for an F-150.

Plus-One Tire Upgrades for the F-350

Plus-one means going up one inch in overall diameter without changing your wheel size or lifting the truck. It's the sweet spot for owners who want a meaner stance and more sidewall for gravel roads, without touching the suspension or throwing off the speedometer.

The math is simple: keep overall diameter within about an inch of stock and the speedometer error stays under 1.5%. Most states allow up to 3%. You're fine.

Plus-One on 18-Inch Wheels

If you're on the base LT275/70R18, the plus-one is LT285/70R18. You gain about half an inch of sidewall and a hair over an inch of tread width. Diameter goes from roughly 33.2 to 33.7 inches. Zero rubbing on a stock SRW F-350. Owners on the Powerstroke forums report zero speedometer recalibration needed at that step.

Plus-One on 20-Inch Wheels

For the LT275/65R20 trucks (Lariat and above), the plus-one is LT285/65R20. Same story: half-inch of extra sidewall, wider footprint on loose surfaces, no lift needed. Overall diameter moves from 34.1 to 34.6 inches.

A 2022 Lariat owner I know runs LT285/65R20 Falken Wildpeaks and hasn't had to touch a thing. He also doesn't hate his fuel economy, which happens fast if you jump straight to 35s.

Off-Road Tire Options and Lift Requirements

This is where the marketing gets loud and the physics gets ignored. A "35-inch" tire on an F-350 is almost never actually 35 inches. LT315/70R17 measures 34.4 inches. LT315/60R20 measures 34.9. Close enough that everyone calls them 35s, but not the same as a true 37.

35-Inch Tires: What You Need

To clear a true 35-inch tire on an SRW F-350, you need a 2-inch leveling kit at minimum. The Super Duty sits with a factory rake (nose down, tail up). A leveling kit evens the front out. Without it, you'll rub the inner fender liner at full lock every time you back into a parking spot.

Wheel backspacing matters too. Stock 20s run about 6.2 inches of backspacing. Drop to 5 inches with a 35-inch tire and you clear the suspension components at full articulation.

37-Inch Tires: Serious Commitment

37s (LT37x12.50R17 or similar) need a 4-inch suspension lift. You'll also want extended brake lines, a track bar drop bracket, and honestly, a re-gear. Ford's factory 3.55 or 3.73 axle ratio was calibrated for stock tire diameter. Slap 37s on there and your effective ratio drops. The truck feels sluggish, the trans hunts, and you'll burn a torque converter towing anything heavy.

The other thing nobody mentions: the F-350 runs a solid front axle with CV-style U-joints. Oversized tires increase the loading on those joints at full steering lock. Owners running 37s without a wheel-offset correction see U-joint wear at 40,000 miles instead of 100,000.

Mud-terrain vs. all-terrain? For a truck that sees more highway than trail, an aggressive all-terrain (Wildpeak AT3W, Ridge Grappler, KO2) gets you 80% of the look with 20% of the road noise. Save the mud-terrains for a truck that actually spends weekends in the mud.

Tire Load Rating and Payload: What F-350 Owners Get Wrong

Here's where the tire shop counter guy sometimes steers people wrong. A cheaper Load Range D tire will physically bolt on. It'll roll down the road. But on paper and in a DOT stop, it's a problem.

The F-350 GVWR runs from about 11,000 lb on a base SRW crew cab up to 14,000 lb on a dually. Take four Load Range E LT275/70R18s at 3,195 lb per tire at max inflation, and you get 12,780 lb of tire capacity. That's the entire truck's rated weight. Drop to Load Range D (roughly 2,680 lb per tire), and you cap at 10,720 lb. That's below the GVWR of every F-350 in the lineup.

That means: if you're loaded to spec, your tires are overloaded. Insurance companies and DOT enforcement both look at this after an incident.

For commercial and fleet use, Load Range E isn't optional. It's the tire spec required to legally operate at the truck's rated weight. Owner-operators pulling gooseneck trailers, hotshot guys, anyone with a slide-in camper. Same rule.

Stick with E. The extra $30 per tire is cheaper than the citation.

Wheel Size and Backspacing Compatibility

Before you buy wheels, know two things: your bolt pattern and your backspacing. Get either wrong and the wheels either won't fit or will destroy your bearings.

Every 2017+ F-350 Super Duty runs an 8x170mm bolt pattern. Not 8x165.1. Not 8-on-6.5. This pattern is Ford Super Duty specific. You can't swap wheels off an older 8-lug Ford. Some 2005-2010 F-250/F-350s used 8x170mm too, so those cross over. Anything from the '99-'04 era used a different pattern.

Backspacing on stock wheels sits around 6.2 inches for 20s and 5.7 for 18s. Aftermarket wheels for lifted trucks typically run 4.5 to 5 inches of backspacing to push the tire outward and clear larger rubber. Go too aggressive (under 4 inches) and you'll load the wheel bearings way past design spec. Bearings start howling at 30,000 miles.

Dually setups add another wrinkle: DRW rear wheels are usually 6.75 inches wide, while SRW rears run 8 to 8.5 inches. Not interchangeable. Hub-centric rings matter too. Aftermarket wheels rarely match Ford's hub bore exactly, and running lug-centric on a Super Duty causes vibration you'll never chase down.

Keeping Your F-350 Interior in Shape After the Build

Here's the part nobody thinks about after they've dropped $2,400 on tires and $800 on a leveling kit: the inside of the truck.

The first weekend you take that new setup out on a gravel road or a job site, mud gets tracked in. Fine dust from the tire tread coats the driver's floorboard. A worn Carhartt sleeve grinds against the outer bolster of the driver's seat every time you climb in. Factory cloth on an XL or leatherette on a Lariat doesn't hold up to that for long. I've watched a guy replace the driver's seat foam on a 2019 F-350 at 90,000 miles because the bolster was gone.

That's the moment covers earn their keep. A set of made-to-fit seat covers built for the F-350 cab takes the mud, the dust, and the tool belt abuse instead of your seats. If you're comparing options across trims and cabs, our seat cover options across every vehicle category page lays them out by fitment.

While you're squaring the cab away, a lot of guys ask about steering wheel wrap sizing too. Learn how to find the right steering wheel cover size for your truck, which covers the F-Series specifically. Also check whether steering wheel covers fit every truck the same way to settle the one-size-fits-all question.

For folks stepping across the Blue Oval lineup, the same tailored approach carries over to the Bronco. Check the tailored covers cut for the 2023 Bronco 2-Door if you've got one in the fleet.

Frequently Asked Questions

Q: What is the stock tire size on a 2023 Ford F-350?

The 2023 F-350 XL and XLT ship with LT275/70R18 on 18-inch wheels. Lariat and higher trims with the 20-inch package run LT275/65R20. Both are Load Range E. If you ordered the Tremor package, you're on LT285/75R18 from the factory. Ford put what most guys call a "34" on it straight from the plant. Check your door-jamb sticker to confirm your exact build.

Q: Can I put 35-inch tires on an F-350 without a lift?

Not without rubbing. On most SRW F-350 setups, a 2-inch leveling kit is the minimum needed to clear a true 35-inch tire (LT315/70R17 or LT315/60R20) at full steering lock. Without the level, you'll rub the inner fender liner every time you back into a parking spot. Some guys get away with 34.4-inch tires and aggressive trimming, but the leveling kit is cheaper and cleaner.

Q: What load range do I need for an F-350?

Load Range E (the 10-ply rating) is Ford's minimum for F-350 applications. Four Load Range E tires at max load index total about 12,780 lb of capacity, matching the truck's GVWR band. Dropping to Load Range D caps you around 10,720 lb, below the GVWR of every F-350 in the lineup. That means loaded to spec, D-rated tires are overloaded. Stick with E.

Q: What is the bolt pattern on a Ford F-350?

All 2017+ F-350 Super Duty trucks use an 8x170mm bolt pattern. This is different from older Ford trucks (pre-1999) that used 8x165.1mm or other patterns, so wheels don't cross-swap. Some 2005-2010 F-250/F-350s also used 8x170mm, so those work. Always confirm the pattern before buying aftermarket wheels. A set that "looks like it fits" but is off by 5mm will destroy your studs.

Q: Will a plus-one tire size throw off my F-350 speedometer?

Not enough to matter. A plus-one step (like LT285/65R20 over stock LT275/65R20) changes overall diameter by less than an inch. That translates to a speedometer error under 1.5%, well within most states' 3% legal tolerance. No recalibration needed. Jump to a full 35-inch tire, though, and you're looking at 4-5% error. That's when you want a Superchips tuner or an ODBII programmer to correct it.

Q: Do F-350 DRW and SRW trucks use the same tires?

No. DRW (dually) rear tires are narrower, typically LT225/75R17, so two of them fit side by side inside the fender without touching. SRW rears run the same wider size as the fronts (LT275/70R18 or LT275/65R20). If you're pricing tires on a dually, you're buying six total: two fronts at the wider size and four rears at LT225/75R17. Don't let a shop quote you four.

You just spent real money getting the right rubber under your F-350. See the made-to-fit seat covers for Ford Super Duty cabs built to protect the interior that goes with it. Keep the cab looking as good as the stance.