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255/70R15 in inches

A 255/70R15 tire is 29.1″ tall and 10.0″ wide, and fits a 15″ wheel. In inches it is written 29.1×10.0R15.

Diameter29.06″
Width10.04″
Sidewall7.03″
255/70R15 drawn to scale: 29.06 inch diameter, 7.03 inch sidewall, 15 inch wheel, 10.04 inch tread width15″ wheel7.03″29.06″ overall10.04″ wideSide view
Drawn to scale. Nominal dimensions calculated from the size code.
Manufacturer data

How tall 255/70R15 tires really are

Heights published by BFGoodrich and General for all 3 tires in this size. Their published revolutions per mile work out to 28.2″ under load (below).

Real 255/70R15 tires measure 29.10″, against 29.06″ from the size code. Every one runs taller than the size code.

Height under load28.2″

Published revs per mile (715) mean the tire rolls like a 28.2″ tire on the vehicle. Use this for speedometer calibration.

Weight spread32.4–35.6 lb

The lightest (General Grabber H/T, SL) is 3.2 lb lighter per corner than the heaviest (BFGoodrich Radial T/A, SL).

3 tires in 255/70R15

Sort by the spec you care about.

LoadRevs/miSource
General Grabber H/THighwaySL · 108T29.1032.412.02,205715Spec page
General Grabber HTS60TouringSL · 108S29.1032.412.02,205715Spec page
BFGoodrich Radial T/APerformanceSL · 108S29.1035.612.02,183715Spec page

Is 255/70R15 a 29-inch tire?

≈29″

Yes. The size code works out to 29.06″, and the 3 tires here publish 29.10″, so people call it a 29.

All 29-inch tire sizes, on every wheel size.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

SizeDiameter ″vs 255/70R15Difference
225/75R1528.29-0.77″-2.6%
235/75R1528.88-0.18″-0.6%
235/70R1628.95-0.10″-0.4%
29×11.00R1429.00-0.06″-0.2%
29×9.00R1429.00-0.06″-0.2%
255/65R1629.05-0.00″-0.0%
225/75R1629.29+0.23″+0.8%
265/70R1529.61+0.55″+1.9%
30×10.00R1530.00+0.94″+3.3%
30×9.50R1530.00+0.94″+3.3%

How to read 255/70R15

How to read any tire size

P255/70R15 108S as printed on the tire sidewall, with each part numberedP255/70R15 108S1234567
How P255/70R15 108S is printed on the sidewall. It's the most common code among the 3 tires here (1 of them); tires in this size come in other load and speed ratings too.
1PP-metric

Marks a P-metric (passenger) tire. Sizes with no letter are Euro-metric.

2255Section width

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

370Aspect ratio

A percentage, not a measurement: the sidewall is 70% as tall as the tire is wide, which is 178.5 mm or 7.03 inches.

4RConstruction

Radial construction.

515Wheel diameter

Mounts on a 15-inch wheel. Approved wheel widths run 6.5″ to 8.5″.

6108Load index

Each tire carries up to 2,205 lb (1,000 kg) at its maximum pressure.

7SSpeed rating

Rated for up to 112 mph sustained.

SpecificationInchesMetric
Overall diameter29.06738 mm
Section width10.04255 mm
Sidewall height7.03178.5 mm
Circumference91.32,318 mm
Revolutions per mile (calculated, unloaded)694.1431 per km
Revolutions per mile (published by manufacturers)715444 per km
Approved wheel width6.5–8.5165–216 mm

Speedometer error after switching to 255/70R15

Your actual speed– mph

Questions about 255/70R15

What is 255/70R15 in inches?

29.06 inches tall, 10.04 inches wide, on a 15-inch wheel. Written in inches, that is roughly 29.1×10.0R15.

How much does a 255/70R15 tire weigh?

Between 32.4 lb and 35.6 lb for the 3 tires listed here. The lightest is the General Grabber H/T (SL); the heaviest is the BFGoodrich Radial T/A (SL).

What wheel width do I need for 255/70R15?

Manufacturers approve 6.5–8.5″ wide wheels for this size.

How many revolutions per mile does a 255/70R15 make?

Published figures run 715 revolutions per mile. The calculated figure is 694.1, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 255/70R15 than 235/75R15?

0.18 inches taller on paper (29.06″ vs 28.88″), which raises the axle about 0.09″. Your speedometer will read about 0.6% slow.