2021 Ford F350 — King Ranch 4wd
The 2021 Ford F350 King Ranch 4wd shipped with 4 different factory tire sizes, depending on the wheel package it left the factory with (this can also reflect a staggered front/rear setup). Check your tire sidewall or door placard to confirm which one applies to your vehicle.
This trim shipped with more than one tire size (staggered fitment, front/rear, or optional wheel package). Confirm which one matches your vehicle by checking your tire sidewall or door placard.
275/65R18
| Section width | 275 mm |
|---|---|
| Aspect ratio (sidewall height) | 65% (178.8 mm) |
| Rim diameter | 18" |
| Overall tire diameter | ~32.1" |
| Revolutions per mile | ~629 |
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275/70R18
| Section width | 275 mm |
|---|---|
| Aspect ratio (sidewall height) | 70% (192.5 mm) |
| Rim diameter | 18" |
| Overall tire diameter | ~33.2" |
| Revolutions per mile | ~608 |
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285/75R18
| Section width | 285 mm |
|---|---|
| Aspect ratio (sidewall height) | 75% (213.8 mm) |
| Rim diameter | 18" |
| Overall tire diameter | ~34.8" |
| Revolutions per mile | ~579 |
Compare prices at:
275/65R20
| Section width | 275 mm |
|---|---|
| Aspect ratio (sidewall height) | 65% (178.8 mm) |
| Rim diameter | 20" |
| Overall tire diameter | ~34.1" |
| Revolutions per mile | ~592 |
Compare prices at:
What this size means for your Ford F350
On the 2021 Ford F350 King Ranch 4wd, the factory 275/65R18 measures about 32.1″ in overall diameter with a 178.8 mm (7″) sidewall, and completes roughly 629 revolutions per mile. Its 65-series aspect ratio gives a taller, comfort-biased sidewall that favors ride quality and shrugs off rough pavement. In tire terms it is a passenger (P-metric / Euro-metric) size.
The 275/65R18 and 275/70R18 differ by about 1.1″ (3.4%) in overall diameter; a gap this size is enough to affect speedometer and odometer readings, so confirm which one your vehicle actually left the factory with.
Other 2021 Ford F350 trims
- Dually 245/75R17
- King Ranch 2wd 275/65R18
- Lariat 2wd 275/65R18
- Lariat 4wd 275/65R18 / 275/70R18 / 285/75R18 / 275/65R20
- Limited 275/65R20
- Platinum 275/65R20
- XL 2wd 245/75R17 / 265/70R17 / 275/65R18
- XL 4wd 245/75R17 / 265/70R17 / 275/65R18 / 275/70R18
- XLT 2wd 275/65R18
- XLT 4wd 275/65R18 / 275/70R18 / 285/75R18 / 275/65R20
Ford F350 tire sizes by year
- 2026 Ford F350 245/75R17
- 2025 Ford F350 245/75R17
- 2024 Ford F350 245/75R17
- 2023 Ford F350 245/75R17
- 2022 Ford F350 245/75R17
- 2020 Ford F350 245/75R17
- 2019 Ford F350 245/75R17
- 2018 Ford F350 245/75R17
- 2017 Ford F350 245/75R17
- 2016 Ford F350 245/75R17
How to read a tire size
A tire size like 225/45R17 breaks down into three parts:
the first number is the section width in millimeters
(the tire's width from sidewall to sidewall), the second is the
aspect ratio — the sidewall's height as a percentage of
that width — and the number after the "R" is the rim
diameter in inches. A letter prefix (P or LT) indicates
Passenger or Light Truck construction; its absence usually means
Euro-metric sizing.
Some trucks and off-road tires instead use "flotation" sizing, like
37X12.50R17 — here the numbers are the tire's overall
diameter and width in inches directly, with the rim diameter last.
Always verify against the tire information placard on your driver's-side door jamb or your owner's manual before purchasing — tire size can vary by factory option package even within the same trim.