Data sheet TS-285/75R18 · Size
285/75R18 in inches
285/75R18 is 34.8 in (885 mm) overall diameter by the formula and turns 579 revs per mile. Section width 11.2 in (285 mm).
Fig. 1 — Cross-section
Table 1 — Nominal dimensions
| Item | in | mm |
|---|---|---|
| DOverall diameter | 34.83 | 885 |
| ASection width | 11.22 | 285 |
| BSidewall | 8.42 | 213.8 |
| CRim | 18 | 457.2 |
| Circumference | 109.4 | 2,779 |
| Revs per mile · km | 579 | 360 |
| Measuring rim | 8″ | Kumho LT |
|---|---|---|
| Approved rims | 7.5–9.5″ | 7 LT tires |
Table 2 — Measured range
34.80–35.08″overall diameter, 7 tires from 3 makers (math: 34.83″)
64–70 lbweight, 7 LT versions
16.0–18.9/32″new tread depth
4,080 lbmax load per tire, 7 LT versions, as published
7 LT · 0 Pversions in the makers’ tables we read
All 7 tires ↓Table 3
7 tires in 285/75R18, as published
One row per model and type, from each maker’s size table. LT first, then P-metric; sorted by diameter.
The math says 34.83″. 7 tires from 3 makers measure 34.80″–35.08″. Tallest here: Nitto Ridge Grappler (hybrid terrain), 35.08″. Check the maker’s number before you buy for a tight fit.
| Tire | Type | Diameter | Width | Rims, in | Weight | Tread | Max load |
|---|---|---|---|---|---|---|---|
| Kumho Road Venture RTkumhotireusa.com · Oct 15, 2026 | LT · E 129/126R | 34.80″ | 11.30″ | 7.5–9.5 | 65.2 lb | 17.3/32″ | 4,080 lb @ 80 psi |
| Toyo Open Country A/T IIItoyotires.com · Oct 15, 2026 | LT · E 129/126S | 34.80″ | 11.30″ | 7.5–9.5 | 65.0 lb | 16.5/32″ | 4,080 lb @ 80 psi |
| Toyo Open Country R/T Trailtoyotires.com · Oct 15, 2026 | LT · E 129/126R | 34.80″ | 11.30″ | 7.5–9.5 | 66.0 lb | 16.5/32″ | 4,080 lb @ 80 psi |
| Nitto Recon Grappler A/Tnittotire.com · Oct 15, 2026 | LT · E 129/126R | 34.84″ | 11.26″ | 7.5–9.5 | 63.7 lb | 16.0/32″ | 4,080 lb @ 80 psi |
| Nitto Terra Grappler G3nittotire.com · Oct 15, 2026 | LT · E 129/126R | 34.84″ | 11.26″ | 7.5–9.5 | 64.3 lb | 16.0/32″ | 4,080 lb @ 80 psi |
| Nitto Ridge Grapplernittotire.com · Oct 15, 2026 | LT · E 129/126Q | 35.08″ | 11.26″ | 7.5–9.5 | 69.5 lb | 16.4/32″ | 4,080 lb @ 80 psi |
| Nitto Trail Grappler M/Tnittotire.com · Oct 15, 2026 | LT · E 129/126Q | 35.08″ | 11.26″ | 7.5–9.5 | 69.8 lb | 18.9/32″ | 4,080 lb @ 80 psi |
§ 1
What the size measures
By the formula the nominal 285/75R18 diameter is 34.8 in (885 mm). Section width 11.2 in (285 mm); sidewall height 8.4 in (214 mm); rim 18 in (457 mm).
Circumference 109.4 in (2,779 mm). Revolutions per mile 579 (360 per km).
§ 2
Published measurements
Makers' size tables list 7 tires in 285/75R18 from 3 brands, all LT versions and no P-metric passenger versions. Load range E is listed. Published diameters run 34.8–35.08 in versus 34.83 in by the formula.
Published weights 63.7–69.8 lbs. New tread depths 16/32–18.9/32 in.
- Kumho Road Venture RT: diameter 34.8 in; section width on measuring rim 11.3 in; weight 65.2 lbs; tread depth 17.3/32 in; max load 4,080 lbs at 80 psi.
- Toyo Open Country A/T III: diameter 34.8 in; inflated width 11.3 in; weight 65 lbs; tread depth 16.5/32 in; 596 revs per mile; max load 4,080 lbs at 80 psi.
- Nitto Trail Grappler M/T: diameter 35.08 in; inflated width 11.26 in; weight 69.8 lbs; tread depth 18.9/32 in; max load 4,080 lbs at 80 psi.
§ 3
Closest sizes and changes
The neighbor table uses a ±3% overall-diameter window, a tire-shop rule of thumb, not a law. Sizes within it include 305/70R18 (34.8 in, −0.1%) and several 35-inch neighbors (about +0.5%).
To 305/70R18 the diameter change is −0.1% and indicated 60 mph stays 60.0 mph. To 35x10.50R17 the change is +0.5% and indicated 60 mph becomes about 60.3 mph. Use the speedometer calculator or the comparison tool for other neighbors.
- 305/70R18: diameter 34.8 in, revs per mile unchanged (579 → 579); true speed 60.0 mph at 60 indicated.
- 35x10.50R17: diameter 35.0 in (+0.5%); revs per mile 579 → 576; true speed about 60.3 mph at 60 indicated.
Fig. 2
285/75R18 and the sizes next to it
To scale, on one ground line. Diameter by the formula.
Table 4
Compare 285/75R18 with another size
Type any size: diameter, sidewall, speedometer and clearance change against this one.
Comparison
295/75R18 is 35.42″ tall, +1.70% against 285/75R18. At 60 mph on the dial you drive 61.0 mph.
| Item | 285/75R18 | 295/75R18 | Change |
|---|---|---|---|
| Overall diameter | 34.83″ | 35.42″ | +0.59″ +1.70% |
| Section width | 11.22″ | 11.61″ | +0.39″ |
| Sidewall | 8.42″ | 8.71″ | +0.30″ |
| Circumference | 109.4″ | 111.3″ | +1.9″ |
| Revs per mile | 579 | 569 | −10 |
| Axle height | 17.42″ | 17.71″ | +0.30″ |
When the odometer counts 1,000 miles, you have driven 1,017.0 miles.
Engine RPM at the same road speed: −1.7%. Gear ratio calculator
Speedometer
| Dial shows | True speed | Difference |
|---|---|---|
| 30 mph | 30.5 mph | +0.5 |
| 45 mph | 45.8 mph | +0.8 |
| 60 mph | 61.0 mph | +1.0 |
| 70 mph | 71.2 mph | +1.2 |
| 80 mph | 81.4 mph | +1.4 |
285/75R18295/75R18
Note 1
P-metric or LT in the same size
7 LT and 0 P versions in the tables we read.
No single model in our tables is published in both P and LT versions of 285/75R18; Table 3 lists both types side by side.
On trucks and SUVs, the load ratings of the tires on an axle must add up to at least the axle’s GAWR on the certification label (49 CFR 571.110).
Vehicles on 285/75R18: not listed yet. We add a vehicle here only from its maker’s own spec sheet for that year and trim.
The size your vehicle left the factory on is printed on the tire and loading placard on the driver’s door jamb (49 CFR 571.110). Pressure and load: that placard too.
Table 5
Within 3% of 285/75R18
Same rim or ±1″, diameter within 3%. A shop rule of thumb, not a law.
| Size | Diameter | Width | vs 285/75R18 | At 60 mph | Clearance |
|---|---|---|---|---|---|
| 305/70R18 | 34.81″ | 12.0″ | −0.1% | 60.0 | −0.01″ |
| 35x10.50R17 | 35.00″ | 10.5″ | +0.5% | 60.3 | +0.08″ |
| 35x11.50R17 | 35.00″ | 11.5″ | +0.5% | 60.3 | +0.08″ |
| 35x11.50R18 | 35.00″ | 11.5″ | +0.5% | 60.3 | +0.08″ |
| 35x12.50R17 | 35.00″ | 12.5″ | +0.5% | 60.3 | +0.08″ |
| 35x12.50R18 | 35.00″ | 12.5″ | +0.5% | 60.3 | +0.08″ |
| 325/65R18 | 34.63″ | 12.8″ | −0.6% | 59.7 | −0.10″ |
| 295/75R17 | 34.42″ | 11.6″ | −1.2% | 59.3 | −0.20″ |
| 315/70R17 | 34.36″ | 12.4″ | −1.3% | 59.2 | −0.23″ |
| 295/70R18 | 34.26″ | 11.6″ | −1.6% | 59.0 | −0.29″ |
Q&A
Common questions
How wide is a 285/75R18?
By the formula the section width is 11.2 in (285 mm). Makers list measured widths near 11.3 in for several models.
What load range and capacity are common for this size?
Makers list 285/75R18 as LT with load range E. Several makers list max load 4,080 lbs at 80 psi; the tire sidewall shows the maximum load rating and, for LT tires, the load range letter (49 CFR 571.139).
Will my speedometer change with this size?
305/70R18 shows no change (true speed 60.0 mph at 60 indicated); 35x10.50R17 shows a small increase (about 60.3 mph at 60 indicated). Results depend on the exact neighbor and wheel.
Where do I find the vehicle maker’s recommended tire pressure?
See the tire and loading placard on the driver’s door jamb for the vehicle maker’s recommended cold tire inflation pressures (49 CFR 571.110).
Notes
Method and sources
Each number and rule comes from a source with the date it was checked.
- Sidewall = width × aspect ratio ÷ 100
- Diameter = rim × 25.4 + 2 × sidewall (mm)
- Revs per mile = 63,360 ÷ (π × diameter, in)
- True speed = dial × new diameter ÷ old diameter
- Clearance change = half the diameter change
Numbers are nominal: the tire unloaded, on its measuring rim. Revs per mile published by makers run higher than the formula. “Within 3%” is a rule of thumb tire shops use, not a law. Tire pressure: the placard on your door jamb.
- Kumho: size table (kumhotireusa.com)checked Oct 15, 2026
- Toyo: size table (toyotires.com)checked Oct 15, 2026
- Nitto: size table (nittotire.com)checked Oct 15, 2026
- 49 CFR 571.139 (FMVSS No. 139), S5.5(d)ecfr.gov · checked Oct 15, 2026
- 49 CFR 571.110 (FMVSS No. 110), S4.3ecfr.gov · checked Oct 15, 2026
Related
Calculators and size classes
- Tire size calculatorTwo sizes: diameter, sidewall, revs and speedometer.
- Compare up to 4 sizesUp to four sizes side by side, drawn to scale.
- Metric ↔ inchesMetric to inches, and 33x12.50R20 to metric.
- Speedometer errorTrue speed after a size change.
- Gear ratio and RPMEngine RPM and the ratio to regear to.
- Wheel offset and pokeBackspacing, poke and inner clearance.
- DOT date codeHow old a tire is, from the DOT number.
- Load index chartLoad index in pounds and kilograms.
- Bolt patternMeasure it, convert inches to mm.
- Rim size and tire fitWhat 17x8 ET35 means, which sizes go on it.
- What fits my carStart from the placard on the door.
- Tire size chartCommon sizes in inches, by rim.