Data sheet TS-C03 · Comparison
265/70R17 vs 285/70R17
285/70R17 is nominally 1.10 in taller than 265/70R17, a 3.5% diameter increase by the formula. It is also wider, has a taller sidewall and turns fewer revolutions per mile.
Fig. 1 — Cross-section, size 2
Table 1 — Data
285/70R17 is 32.71″ tall, +3.49% against 265/70R17. At 60 mph on the dial you drive 62.1 mph.
| Item | 265/70R17 | 285/70R17 | Change |
|---|---|---|---|
| DOverall diameter | 31.61″ | 32.71″ | +3.49% |
| ASection width | 10.43″ | 11.22″ | +0.79″ |
| BSidewall | 7.30″ | 7.85″ | +0.55″ |
| CRim | 17″ | 17″ | same |
| Revs per mile | 638 | 617 | −22 |
| Dial 60 mph = | 60.0 | 62.1 | +3.5% |
| Axle height | 15.80″ | 16.35″ | +0.55″ |
+3.49% — outside the ±3% rule of thumb tire shops use. Expect a speedometer error, and check clearance at full lock and full compression before you buy.
Where to buy 285/70R17 ↓Fig. 2
Side view and width, to scale
Size 1 dashed, size 2 solid, on one ground line.
265/70R17285/70R17
Table 2 — Speedometer
| Dial shows | True speed | Difference |
|---|---|---|
| 30 mph | 31.0 mph | +1.0 |
| 45 mph | 46.6 mph | +1.6 |
| 60 mph | 62.1 mph | +2.1 |
| 70 mph | 72.4 mph | +2.4 |
| 80 mph | 82.8 mph | +2.8 |
Engine RPM at the same road speed: −3.4%. Gear ratio calculator
Table 3
Published dimensions
From each maker’s size table. A tire is listed only with a source.
The math says 32.71″. 28 tires from 5 makers measure 32.76″–33.15″. Tallest here: Nitto Trail Grappler M/T (mud-terrain), 33.15″. Check the maker’s number before you buy for a tight fit.
| Tire | Type | Diameter | Width | Rims, in | Weight | Tread | Max load |
|---|---|---|---|---|---|---|---|
| Nitto Ridge Grapplernittotire.com · Oct 15, 2026 | LT · E 121/118Q | 32.76″ | 11.50″ | 7.5–9.5 | 57.9 lb | 16.4/32″ | 3,195 lb @ 80 psi |
| Nitto Recon Grappler A/Tnittotire.com · Oct 15, 2026 | LT · E 126/123S | 32.76″ | 11.50″ | 7.5–9.5 | 54.6 lb | 16.0/32″ | 3,750 lb @ 80 psi |
| Nitto Terra Grappler G3nittotire.com · Oct 15, 2026 | LT · E 126/123S | 32.76″ | 11.50″ | 7.5–9.5 | 56.2 lb | 16.0/32″ | 3,750 lb @ 80 psi |
| Nitto Dura Grapplernittotire.com · Oct 15, 2026 | LT · E 126/123R | 32.79″ | 11.49″ | 7.5–9.5 | 55.3 lb | 16.9/32″ | 3,750 lb @ 80 psi |
| Firestone Destination X/Tfirestonetire.com · Oct 15, 2026 | LT · E 121S | 32.80″ | — | 7.5–9.0 | 50.2 lb | 16.0/32″ | — |
| Firestone Destination M/T2firestonetire.com · Oct 15, 2026 | LT · E 121Q | 32.80″ | — | 7.5–9.0 | 59.5 lb | 20.0/32″ | — |
| Firestone Transforce HT3firestonetire.com · Oct 15, 2026 | LT · E 126R | 32.80″ | — | 7.5–9.0 | 49.7 lb | 15.0/32″ | — |
| Firestone Transforce AT2firestonetire.com · Oct 15, 2026 | LT · E 121R | 32.80″ | — | 7.5–9.0 | 50.1 lb | 18.0/32″ | — |
| Kumho Road Venture AT52kumhotireusa.com · Oct 15, 2026 | LT · E 121/118R | 32.80″ | 11.50″ | 7.5–9.5 | 54.6 lb | 16.0/32″ | 3,195 lb @ 80 psi |
| Kumho Road Venture RTkumhotireusa.com · Oct 15, 2026 | LT · E 121/118R | 32.80″ | 11.50″ | 7.5–9.5 | 60.8 lb | 17.3/32″ | 3,195 lb @ 80 psi |
§ 1
How much taller and wider?
By the formula, diameter rises from 31.6 in (803 mm) to 32.7 in (831 mm). Section width rises from 10.4 to 11.2 in, a 20 mm increase. Sidewall height rises from 7.3 to 7.9 in, an increase of 14 mm.
Nominal revolutions per mile fall from 638 to 617. Ground clearance at the axle increases by 0.55 in (14 mm). The scale drawing and differences table show these unloaded nominal changes; actual tire measurements vary.
§ 2
What changes in speed and gearing?
With calibration unchanged, a nominal change to 285/70R17 means 60 mph indicated becomes 62.1 mph true. At 100 km/h indicated, true speed is 103.5 km/h. Actual distance traveled is likewise 3.5% greater than the odometer indicates.
By the formula, at 65 mph with a 3.73 axle ratio and a 1.00 transmission gear, engine speed falls from 2,578 to 2,492 rpm, down 3.4%. The calculated axle ratio that restores the original engine speed is 3.86: 3.73 × 32.71 / 31.61. The gear ratio calculator shows this mathematical relationship, not a modification recommendation.
§ 3
What do maker tables list?
The Kumho, Firestone, Nitto, Toyo and Mickey Thompson size tables list 33 tires in 265/70R17 and 28 in 285/70R17. Their published diameter ranges are 31.6 to 32 in for 265/70R17 and 32.76 to 33.15 in for 285/70R17. Each group includes 21 LT versions; the remaining versions are P-metric or passenger tires. Listed load ranges are SL, XL and E for 265/70R17, versus SL and E for 285/70R17.
§ 4
Which changes matter for your vehicle?
The taller 285/70R17 adds nominal axle clearance and reduces engine rpm at the same road speed. Its greater diameter and width also require more space around the tire. The shorter, narrower 265/70R17 retains the smaller dimensions and higher calculated rpm.
Fit depends on the vehicle, wheels and suspension. Use the measured-model tables to compare individual tires rather than treating every tire with the same size marking as identical.
Table 4
Sizes within 3% of 285/70R17
Same rim or ±1″, diameter within 3%. A shop rule of thumb, not a law.
| Size | Diameter | Width | vs 285/70R17 | At 60 mph | Clearance |
|---|---|---|---|---|---|
| 235/80R18 | 32.80″ | 9.3″ | +0.3% | 60.2 | +0.05″ |
| 305/65R17 | 32.61″ | 12.0″ | −0.3% | 59.8 | −0.05″ |
| 265/70R18 | 32.61″ | 10.4″ | −0.3% | 59.8 | −0.05″ |
| 305/70R16 | 32.81″ | 12.0″ | +0.3% | 60.2 | +0.05″ |
| 285/65R18 | 32.59″ | 11.2″ | −0.4% | 59.8 | −0.06″ |
| 285/75R16 | 32.83″ | 11.2″ | +0.4% | 60.2 | +0.06″ |
| 33x11.50R16 | 33.00″ | 11.5″ | +0.9% | 60.5 | +0.15″ |
| 33x11.50R17 | 33.00″ | 11.5″ | +0.9% | 60.5 | +0.15″ |
| 33x11.50R18 | 33.00″ | 11.5″ | +0.9% | 60.5 | +0.15″ |
| 33x12.50R17 | 33.00″ | 12.5″ | +0.9% | 60.5 | +0.15″ |
Size sheets
Q&A
Common questions
Is 285/70R17 within 3% of 265/70R17?
No. Its nominal diameter increase is 3.5%, outside the ±3% tire-shop rule of thumb. That guideline is not a law or a vehicle maker specification.
Are both sizes for the same rim diameter?
Both have a nominal 17 in (432 mm) rim diameter. That does not establish compatible rim widths; check the individual maker's rim listing.
Is 285/70R17 exactly 33 inches tall?
No. Nominal diameter is 32.7 in by the formula. Mickey Thompson lists 33 in for the LT285/70R17 Baja Boss A/T.
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.
- Mickey Thompson: size table (mickeythompsontires.com)checked Oct 15, 2026
- 49 CFR 571.139 (FMVSS No. 139), S4.1ecfr.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.