tireheight.com

255/85R17 in inches

A 255/85R17 tire is 34.1″ tall and 10.0″ wide, and fits a 17″ wheel. In inches it is written 34.1×10.0R17.

Diameter34.07″
Width10.04″
Sidewall8.53″
255/85R17 drawn to scale: 34.07 inch diameter, 8.53 inch sidewall, 17 inch wheel, 10.04 inch tread width17″ wheel8.53″34.07″ overall10.04″ wideSide view
Drawn to scale. Nominal dimensions calculated from the size code.
Manufacturer data

How tall 255/85R17 tires really are

Heights published by Mickey Thompson for the one tire in this size.

The one tire listed, the Mickey Thompson Baja Boss A/T, measures 34.60″: 0.53″ taller than the size code's 34.07″.

1 tire in 255/85R17

Sort by the spec you care about.

LoadRevs/miSource
Mickey Thompson Baja Boss A/TAll-terrainLT E · 121Q34.6064.018.53,195–Spec page

Is 255/85R17 a 35-inch tire?

≈35″

Close. The size code works out to 34.07″, and the 1 tire here publishes 34.60″, so people call it a 35.

All 35-inch tire sizes, on every wheel size.

A true 35×10.50R17 is 0.93″ taller on paper and 0.5″ wider.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

SizeDiameter ″vs 255/85R17Difference
295/70R1733.26-0.81″-2.4%
305/70R1733.81-0.26″-0.8%
285/75R1733.83-0.24″-0.7%
34×10.50R1734.00-0.07″-0.2%
295/70R1834.26+0.19″+0.6%
315/70R1734.36+0.30″+0.9%
295/75R1734.42+0.35″+1.0%
35×10.50R1735.00+0.93″+2.7%
35×11.50R1735.00+0.93″+2.7%
35×12.50R1735.00+0.93″+2.7%

How to read 255/85R17

How to read any tire size

LT255/85R17 121Q as printed on the tire sidewall, with each part numberedLT255/85R17 121Q1234567
How LT255/85R17 121Q is printed on the sidewall. It's the most common code among the 1 tire here; tires in this size come in other load and speed ratings too.
1LTLight truck

Marks a light truck (LT) tire.

2255Section width

255 mm across the widest point, or 10.04 inches. Every 255 size

385Aspect ratio

A percentage, not a measurement: the sidewall is 85% as tall as the tire is wide, which is 216.8 mm or 8.53 inches.

4RConstruction

Radial construction.

517Wheel diameter

Mounts on a 17-inch wheel. Approved wheel widths run 6.5″ to 8.0″.

6121Load index

Each tire carries up to 3,195 lb (1,450 kg) at its maximum pressure.

7QSpeed rating

Rated for up to 99 mph sustained.

ELoad range

Printed separately as "LOAD RANGE E": a 10-ply rating, inflated up to 80 psi (standard load-range table). The load range E tires here carry up to 3,195 lb each, as published.

SpecificationInchesMetric
Overall diameter34.07865 mm
Section width10.04255 mm
Sidewall height8.53216.8 mm
Circumference107.02,718 mm
Revolutions per mile (calculated, unloaded)592.0368 per km
Approved wheel width6.5–8.0165–203 mm

Speedometer error after switching to 255/85R17

Your actual speed– mph

Questions about 255/85R17

What is 255/85R17 in inches?

34.07 inches tall, 10.04 inches wide, on a 17-inch wheel. Written in inches, that is roughly 34.1×10.0R17.

What wheel width do I need for 255/85R17?

Manufacturers approve 6.5–8.0″ wide wheels for this size.

How much taller is 255/85R17 than 34×10.50R17?

0.07 inches taller on paper (34.07″ vs 34.00″), which raises the axle about 0.03″. Your speedometer will read about 0.2% slow.