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Size comparisons

265/70R17 vs 285/70R17 — the commonest step in the catalogue

One pairing that appears on five separate platforms, and the reason this site publishes one page per pairing rather than one per truck.

265/70R1731.61 in tall10.43 in wide285/70R1732.71 in tall11.22 in wide+1.10 in · +3.49%
Drawn to scale from the size codes. Solid outline is 265/70R17; dashed outline is 285/70R17. The bars below each tire are section width at the same scale.

285/70R17 is 1.10 in taller than 265/70R17 (3.49%) and 0.79 in wider. A speedometer calibrated for 265/70R17 would under-read by 3.49%.

Measured against each other

  • Overall diameter

    31.61 in32.71 in+1.10 in (+3.49%)

  • Section width

    10.43 in / 265 mm11.22 in / 285 mm+0.79 in (+7.55%)

  • Sidewall height

    7.30 in7.85 in+0.55 in

  • Circumference

    99.3 in102.8 in+3.5 in

  • Revolutions per mile

    638.1616.6-21.5

  • Ride height at the axle

    ——+0.55 in

  • Speedometer reading

    ——+3.49% under-read

Calibrated for 265/70R17, running 285/70R17

Dial reads 30
31.0 mph
Dial reads 50
51.7 mph
Dial reads 70
72.4 mph
Odometer counts 100
103.5 mi covered

Change either size in the comparison tool, or see the full speed table in the speedometer error calculator.

Five vehicles in this catalogue leave the factory on 265/70R17: a mid-size pickup, a body-on-frame SUV, a full-size pickup, another mid-size pickup and a full-size SUV. All five have owners asking the same question about the same next size.

Why one page instead of five

Because the arithmetic is a property of the two tires and nothing else. A Tacoma, a 4Runner, an F-150, a Frontier and a Tahoe fitted with these two sizes all experience the same 1.10 in, the same 3.49%, and the same 0.55 in at the axle. Five pages saying that with a different badge in the first sentence would be five copies of one fact.

What differs between the platforms is what the 0.79 in of extra casing runs into, and that is not derivable from a size code on any of them.

The speedometer under-reads by 3.49%, worth about 2.4 mph at motorway pace, on every one of the five.

What 20 mm is doing to the height

The aspect ratio is unchanged, so the sidewall grows in proportion with the casing — 70% of a bigger number. That is why a change described purely as "wider" delivers 1.10 in of height, which is more than the 0.79 in of width that caused it.

285/70R17 computes to 32.71 in, close enough to 33 inches that the entire aftermarket sells and describes it as a 33. So the step reads as "stock to 33s" while being, in fact, 20 mm of width and an unchanged profile. It is the cheapest possible route to the 33-inch class on a 17-inch wheel and it requires no wheel change.

What differs between the five platforms

Wheel width and offset, mostly — and both are outside this page. A size code fixes the wheel's diameter at 17 in and says nothing about how wide it is, so five platforms all listed as running 265/70R17 are not thereby running the same wheel, and this site records no widths to check against. The mechanism is the reliable part: the narrower the rim under a given casing, the harder it is squeezed — under 11.22 in at its widest point, and marginally taller for it. Spread across five platforms, that is capable of moving the measured figures further apart than the 1.10 in of nominal diameter this comparison is about.

The next rung, and the narrow alternative

Above it, 35x12.50R17 is another 2.29 in. Below and beside it, 275/70R17 is the half-step at 0.55 in, for anyone who wants a particular tread pattern rather than a particular size.

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