235/55R18 in inches

A 235/55R18 tire is 28.2″ tall and 9.3″ wide, and fits a 18″ wheel. In inches it is written 28.2×9.3R18.

Diameter28.18″

Width9.25″

Sidewall5.09″

Drawn to scale. Nominal dimensions calculated from the size code.

Manufacturer data

How tall 235/55R18 tires really are

Heights published by BFGoodrich, General, Michelin and Toyo for all 27 tires in this size. Their published revolutions per mile work out to 27.3–27.4″ under load (below).

Real 235/55R18 tires measure 28.10–28.20″, against 28.18″ from the size code. They run both taller and shorter than the size code.

Height under load27.3–27.4″

Published revs per mile (737–739) mean the tire rolls like a 27.3–27.4″ tire on the vehicle. Use this for speedometer calibration.

Weight spread25.0–35.1 lb

The lightest (General AltiMAX365 AW, SL) is 10.1 lb lighter per corner than the heaviest (BFGoodrich Trail-Terrain T/A+, XL).

27 tires in 235/55R18

Sort by the spec you care about.

	Load					Revs/mi	Source
General AltiMAX365 AWTouring	SL · 100V	28.20	25.0	11.0	1,764	737	Spec page
Toyo Proxes Sport A/SPerformance	SL · 100V	28.15	25.4	10.5	1,764	738	Spec page
General AltiMAX RT45Touring	SL · 100H	28.20	25.4	11.0	1,764	737	Spec page
Michelin Pilot Alpin 5Winter	XL · 104H	28.15	25.8	9.5	1,984	739	Spec page
General AltiMAX RT45Touring	XL · 104V	28.20	25.9	11.0	1,984	737	Spec page
General AltiMAX RT45Touring	SL · 100T	28.20	26.4	11.0	1,764	737	Spec page
Michelin CrossClimate2All-season	XL · 104V	28.15	26.6	10.0	1,984	739	Spec page
Toyo Extensa A/S IIAll-season	SL · 100H	28.15	27.7	11.6	1,764	738	Spec page
Michelin Latitude Sport 3Performance	SL · 100W	28.20	27.9	8.5	1,764	739	Spec page
Michelin Primacy MXM4Touring	SL · 100H	28.20	27.9	9.0	1,764	739	Spec page
General G-MAX AS07Performance	SL · 100W	28.20	28.0	10.0	1,764	737	Spec page
Michelin Primacy MXM4Touring	SL · 100V	28.20	28.0	9.2	1,764	739	Spec page
Michelin Defender2All-season	XL · 104H	28.15	28.4	10.5	1,984	739	Spec page
General AltiMAX Arctic XWinter	XL · 104T	28.20	28.7	12.0	1,984	737	Spec page
Toyo Extensa HP IIPerformance	SL · 100V	28.15	29.1	9.4	1,764	738	Spec page
BFGoodrich Advantage ControlAll-season	SL · 100H	28.15	29.1	11.5	1,764	739	Spec page
Michelin Pilot Sport All-Season 4Performance	XL · 104Y	28.10	29.1	10.0	1,984	739	Spec page
Michelin X-Ice SnowWinter	XL · 104T	28.15	29.1	10.5	1,984	739	Spec page
Toyo Proxes G-Tour	XL · 104V	28.10	29.1	11.8	1,984	738	Spec page
Michelin X-Ice Snow+Winter	XL · 104H	28.15	29.6	10.5	1,984	739	Spec page
Toyo Celsius IITouring	SL · 100V	28.15	29.9	11.2	1,764	738	Spec page
Toyo Celsius SportPerformance	XL · 104V	28.15	30.1	10.5	1,984	738	Spec page
Toyo Observe G3-IceWinter	XL · 104T	28.15	31.5	12.0	1,984	738	Spec page
Toyo OPEN COUNTRY Q/TAll-season	SL · 100V	28.15	31.7	12.0	1,764	738	Spec page
BFGoodrich Elite-Force T/AAll-season	XL · 104W	28.15	32.0	10.0	1,984	739	Spec page
BFGoodrich Trail-Terrain T/AAll-terrain	XL · 104H	28.10	33.5	12.5	1,984	739	Spec page
BFGoodrich Trail-Terrain T/A+	XL · 104H	28.10	35.1	12.5	1,984	739	Spec page

Is 235/55R18 a 28-inch tire?

≈28″

Yes. The size code works out to 28.18″, and the 27 tires here publish 28.10–28.20″, 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.

Size	Diameter ″	vs 235/55R18	Difference
265/45R18	27.39	-0.79″	-2.8%
345/35R18	27.51	-0.67″	-2.4%
245/50R18	27.65	-0.53″	-1.9%
225/55R18	27.74	-0.43″	-1.5%
235/60R17	28.10	-0.07″	-0.3%
235/50R19	28.25	+0.07″	+0.3%
295/40R19	28.29	+0.11″	+0.4%
295/45R18	28.45	+0.28″	+1.0%
245/55R18	28.61	+0.43″	+1.5%
225/60R18	28.63	+0.45″	+1.6%

How to read 235/55R18

How to read any tire size

How 235/55R18 100V is printed on the sidewall. It's the most common code among the 27 tires here (6 of them); tires in this size come in other load and speed ratings too.

1235Section width

235 mm across the widest point, or 9.25 inches. Every 235 size

255Aspect ratio

A percentage, not a measurement: the sidewall is 55% as tall as the tire is wide, which is 129.3 mm or 5.09 inches.

3RConstruction

Radial construction.

418Wheel diameter

Mounts on a 18-inch wheel. Approved wheel widths run 6.5″ to 8.5″.

5100Load index

Each tire carries up to 1,764 lb (800 kg) at its maximum pressure.

6VSpeed rating

Rated for up to 149 mph sustained.

Specification	Inches	Metric
Overall diameter	28.18	716 mm
Section width	9.25	235 mm
Sidewall height	5.09	129.3 mm
Circumference	88.5	2,248 mm
Revolutions per mile (calculated, unloaded)	715.8	445 per km
Revolutions per mile (published by manufacturers)	737–739	458–459 per km
Approved wheel width	6.5–8.5	165–216 mm

Speedometer error after switching to 235/55R18

Your actual speed– mph

Questions about 235/55R18

What is 235/55R18 in inches?

28.18 inches tall, 9.25 inches wide, on a 18-inch wheel. Written in inches, that is roughly 28.2×9.3R18.

How much does a 235/55R18 tire weigh?

Between 25.0 lb and 35.1 lb for the 27 tires listed here. The lightest is the General AltiMAX365 AW (SL); the heaviest is the BFGoodrich Trail-Terrain T/A+ (XL).

What wheel width do I need for 235/55R18?

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

How many revolutions per mile does a 235/55R18 make?

Published figures run 737–739 revolutions per mile. The calculated figure is 715.8, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 235/55R18 than 225/55R18?

0.43 inches taller on paper (28.18″ vs 27.74″), which raises the axle about 0.22″. Your speedometer will read about 1.6% slow.