Data sheet TS-C08 · Comparison
245/75R17 vs 265/70R17
265/70R17 is 0.4% taller than 245/75R17 by the formula, adding 0.14 in of diameter. Its larger change is width: nominal section width increases from 9.6 to 10.4 in, a difference of 20 mm.
Fig. 1 — Cross-section, size 2
Table 1 — Data
265/70R17 is 31.61″ tall, +0.44% against 245/75R17. At 60 mph on the dial you drive 60.3 mph.
| Item | 245/75R17 | 265/70R17 | Change |
|---|---|---|---|
| DOverall diameter | 31.47″ | 31.61″ | +0.44% |
| ASection width | 9.65″ | 10.43″ | +0.79″ |
| BSidewall | 7.23″ | 7.30″ | +0.07″ |
| CRim | 17″ | 17″ | same |
| Revs per mile | 641 | 638 | −3 |
| Dial 60 mph = | 60.0 | 60.3 | +0.4% |
| Axle height | 15.73″ | 15.80″ | +0.07″ |
+0.44% — within the ±3% rule of thumb tire shops use. The speedometer and gearing stay close to stock.
Where to buy 265/70R17 ↓Fig. 2
Side view and width, to scale
Size 1 dashed, size 2 solid, on one ground line.
245/75R17265/70R17
Table 2 — Speedometer
| Dial shows | True speed | Difference |
|---|---|---|
| 30 mph | 30.1 mph | +0.1 |
| 45 mph | 45.2 mph | +0.2 |
| 60 mph | 60.3 mph | +0.3 |
| 70 mph | 70.3 mph | +0.3 |
| 80 mph | 80.4 mph | +0.4 |
Engine RPM at the same road speed: −0.4%. Gear ratio calculator
Table 3
Published dimensions
From each maker’s size table. A tire is listed only with a source.
The math says 31.61″. 33 tires from 5 makers measure 31.60″–32.00″. Tallest here: Toyo Open Country M/T (mud-terrain), 32.00″. 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 121/118R | 31.60″ | 10.70″ | 7.0–9.0 | 54.6 lb | 17.3/32″ | 3,195 lb @ 80 psi |
| Firestone Winterforce LTfirestonetire.com · Oct 15, 2026 | LT · E 121R | 31.65″ | — | 7.0–8.5 | 49.9 lb | 18.0/32″ | — |
| Nitto Ridge Grapplernittotire.com · Oct 15, 2026 | LT · E 121/118Q | 31.65″ | 10.71″ | 7.0–9.0 | 54.5 lb | 16.4/32″ | 3,195 lb @ 80 psi |
| Nitto Recon Grappler A/Tnittotire.com · Oct 15, 2026 | LT · E 123/120S | 31.65″ | 10.71″ | 7.0–9.0 | 51.0 lb | 15.7/32″ | 3,415 lb @ 80 psi |
| Nitto Terra Grappler G3nittotire.com · Oct 15, 2026 | LT · E 123/120S | 31.65″ | 10.71″ | 7.0–9.0 | 48.7 lb | 15.7/32″ | 3,415 lb @ 80 psi |
| Nitto Dura Grapplernittotire.com · Oct 15, 2026 | LT · E 121/118Q | 31.65″ | 10.71″ | 7.0–9.0 | 50.7 lb | 16.8/32″ | 3,195 lb @ 80 psi |
| Firestone Destination X/Tfirestonetire.com · Oct 15, 2026 | LT · E 121S | 31.70″ | — | 7.0–8.5 | 45.6 lb | 15.0/32″ | — |
| Firestone Destination M/T2firestonetire.com · Oct 15, 2026 | LT · E 121Q | 31.70″ | — | 7.0–8.5 | 53.3 lb | 19.0/32″ | — |
| Firestone Transforce HT3firestonetire.com · Oct 15, 2026 | LT · E 123R | 31.70″ | — | 7.0–8.5 | 44.6 lb | 15.0/32″ | — |
| Firestone Transforce AT2firestonetire.com · Oct 15, 2026 | LT · E 121R | 31.70″ | — | 7.0–8.5 | 44.7 lb | 17.0/32″ | — |
§ 1
What changes in size and clearance?
Nominal diameter increases from 31.5 in (799 mm) to 31.6 in (803 mm). Sidewall height rises from 7.2 in (184 mm) to 7.3 in (186 mm). Revolutions per mile decrease from 641 to 638, while ground clearance at the axle increases by 0.07 in (2 mm).
The scale drawing and differences table show these unloaded, formula-based dimensions. Actual tire measurements vary by model.
§ 2
How do speedometer readings and gearing change?
By the formula, changing to 265/70R17 gives 60.3 mph true speed at 60 mph indicated, or 100.4 km/h at 100 km/h indicated. Actual distance traveled is likewise 0.4% greater than the odometer records. At 65 mph with a 3.73 axle ratio and a 1.00 transmission gear, nominal engine speed drops from 2,590 to 2,578 rpm. The calculated axle ratio restoring the original engine speed is 3.75; this is formula math, not a modification recommendation.
§ 3
What do the maker tables list?
The Firestone, Kumho, Nitto and Toyo tables shown here contain 13 tires in 245/75R17, all listing 31.5 in diameter. For 265/70R17, the tables from those makers plus Mickey Thompson contain 33 tires, with published diameters from 31.6 to 32 in. Both groups include SL, XL and E load ranges.
Toyo lists its Open Country A/T III at 31.5 in for LT245/75R17 and 31.7 in for LT265/70R17. Toyo also lists 660 and 656 revs per mile, respectively, rather than the nominal formula results.
§ 4
Which differences matter for your vehicle?
For added axle clearance, 265/70R17 provides only a small nominal increase and slightly lowers engine rpm at the same road speed. For a narrower section width, 245/75R17 measures less across by the formula. The wider, slightly taller size changes the clearance requirements; fit depends on the vehicle, wheels and suspension.
Compare the specific model rows, not just the size labels. Published diameter, load range and approved rim widths can differ between tires.
Table 4
Sizes within 3% of 265/70R17
Same rim or ±1″, diameter within 3%. A shop rule of thumb, not a law.
| Size | Diameter | Width | vs 265/70R17 | At 60 mph | Clearance |
|---|---|---|---|---|---|
| 265/65R18 | 31.56″ | 10.4″ | −0.1% | 59.9 | −0.02″ |
| 265/75R16 | 31.65″ | 10.4″ | +0.1% | 60.1 | +0.02″ |
| 285/70R16 | 31.71″ | 11.2″ | +0.3% | 60.2 | +0.05″ |
| 235/85R16 | 31.73″ | 9.3″ | +0.4% | 60.2 | +0.06″ |
| 245/75R17 | 31.47″ | 9.6″ | −0.4% | 59.7 | −0.07″ |
| 285/60R18 | 31.46″ | 11.2″ | −0.4% | 59.7 | −0.07″ |
| 235/80R17 | 31.80″ | 9.3″ | +0.6% | 60.4 | +0.10″ |
| 275/70R16 | 31.16″ | 10.8″ | −1.4% | 59.1 | −0.22″ |
| 255/70R18 | 32.06″ | 10.0″ | +1.4% | 60.9 | +0.22″ |
| 255/75R17 | 32.06″ | 10.0″ | +1.4% | 60.9 | +0.23″ |
Size sheets
Q&A
Common questions
Is 265/70R17 within 3% of 245/75R17?
Yes. The nominal diameter difference is +0.4%, inside the ±3% window. That window is a tire-shop rule of thumb, not a law or vehicle maker specification.
Do both sizes use the same wheel diameter?
Both specify a nominal 17 in (432 mm) rim diameter. Approved rim widths still depend on the tire: Toyo lists 6.5–8.0 in for its LT245/75R17 Open Country A/T III and 7.0–9.0 in for LT265/70R17.
Does 265/70R17 have a taller sidewall?
Yes. By the formula, sidewall height increases from 7.2 in (184 mm) to 7.3 in (186 mm), a difference of 2 mm.
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.
- Toyo: size table (toyotires.com)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.