tireheight.com

345/40R17 in inches

A 345/40R17 tire is 27.9″ tall and 13.6″ wide, and fits a 17″ wheel. In inches it is written 27.9×13.6R17.

Diameter27.87″
Width13.58″
Sidewall5.43″
345/40R17 drawn to scale: 27.87 inch diameter, 5.43 inch sidewall, 17 inch wheel, 13.58 inch tread width17″ wheel5.43″27.87″ overall13.58″ wideSide view
Drawn to scale. Nominal dimensions calculated from the size code.
Manufacturer data

How tall 345/40R17 tires really are

Heights published by Toyo for the one tire in this size. Their published revolutions per mile work out to 26.9″ under load (below).

The one tire listed, the Toyo Proxes TQ, measures 27.72″: 0.15″ shorter than the size code's 27.87″.

Height under load26.9″

Published revs per mile (749) mean the tire rolls like a 26.9″ tire on the vehicle. Use this for speedometer calibration.

1 tire in 345/40R17

Sort by the spec you care about.

LoadRevs/miSource
Toyo Proxes TQPerformanceLL27.7235.96.32,094749Spec page

Is 345/40R17 a 28-inch tire?

≈28″

Yes. The size code works out to 27.87″, and the 1 tire here publishes 27.72″, so people call it a 28.

All 28-inch tire sizes, on every wheel size.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

SizeDiameter ″vs 345/40R17Difference
215/60R1727.16-0.71″-2.5%
235/55R1727.18-0.69″-2.5%
225/60R1727.63-0.24″-0.8%
225/55R1827.74-0.12″-0.4%
215/70R1627.85-0.02″-0.1%
215/65R1728.00+0.14″+0.5%
235/65R1628.03+0.16″+0.6%
235/60R1728.10+0.24″+0.8%
225/65R1728.52+0.65″+2.3%
245/60R1728.57+0.71″+2.5%

How to read 345/40R17

How to read any tire size

P345/40R17 as printed on the tire sidewall, with each part numberedP345/40R1712345
How P345/40R17 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.
1PP-metric

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

2345Section width

345 mm across the widest point, or 13.58 inches. Every 345 size

340Aspect ratio

A percentage, not a measurement: the sidewall is 40% as tall as the tire is wide, which is 138.0 mm or 5.43 inches.

4RConstruction

Radial construction.

517Wheel diameter

Mounts on a 17-inch wheel. Approved wheel widths run 11.5″ to 13.5″.

SpecificationInchesMetric
Overall diameter27.87708 mm
Section width13.58345 mm
Sidewall height5.43138.0 mm
Circumference87.52,224 mm
Revolutions per mile (calculated, unloaded)723.7450 per km
Revolutions per mile (published by manufacturers)749465 per km
Approved wheel width11.5–13.5292–343 mm

Speedometer error after switching to 345/40R17

Your actual speed– mph

Questions about 345/40R17

What is 345/40R17 in inches?

27.87 inches tall, 13.58 inches wide, on a 17-inch wheel. Written in inches, that is roughly 27.9×13.6R17.

What wheel width do I need for 345/40R17?

Manufacturers approve 11.5–13.5″ wide wheels for this size.

How many revolutions per mile does a 345/40R17 make?

Published figures run 749 revolutions per mile. The calculated figure is 723.7, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 345/40R17 than 225/60R17?

0.24 inches taller on paper (27.87″ vs 27.63″), which raises the axle about 0.12″. Your speedometer will read about 0.9% slow.