235/30R18 Tire Size in Inches and Millimeters

235/30R18 tires have a diameter of 23.6" (599 mm), a tread width of 9.3" (235 mm), and a wheel diameter of 18" (457.2 mm).The sidewall of the tire is 2.8" (71 mm), and the tire's circumference is 74.1" (1880.9 mm). This means a 235/30R18 tire will make make 855 revolutions per mile, or 532 revolutions per kilometer.

235/30R18 Tire Front
9.3"
23.6"
235/30R18 Tire Side
Tire Circumference
74.1"
18"
2.8"
855 Revs/Mile
SpecInchesMetric
Diameter23.6"599 mm
Width9.3"235 mm
Wheel18"457.2 mm
Sidewall2.8"71 mm
Circum74.1"1880.9 mm
Revolutions855 per mile532 per km

What Does 235/30R18 Mean?

The tire size 235/30R18 is a common size used on many trucks, SUVs, and other larger vehicles.

Here is what each part of the size designation represents:

  • 235: This number represents the width of the tire in millimeters. In this case, the tire is 235 millimeters wide.
  • 30: This number represents the aspect ratio of the tire, which is the height of the tire's sidewall as a percentage of its width. In this case, the sidewall height is 30% of the tire's width.
  • R: This letter indicates the tire's construction type. “R” stands for radial construction, which is the most common type of tire construction today.
  • 18: This number represents the diameter of the wheel that the tire is designed to fit on, in inches. In this case, the tire is designed to fit on a 18-inch wheel.

235/30R18 tire size meaning

How To Convert 235/30R18 Into Inches

The 235/30R18 conversion is fairly simple. The first number in the tire size, 235, represents the width of the tire in millimeters. To convert this to inches, we divide 235 by 25.4 (since there are 25.4 millimeters in an inch). This gives us approximately 9.3 inches.

The second number in the tire size, 30, represents the aspect ratio or the height of the tire as a percentage of its width. To calculate the height in inches, we multiply 9.3 by 0.30, which gives us approximately 2.8 inches.

Finally, the last number in the tire size, 18, represents the diameter of the wheel rim in inches. Therefore, the tire size 235/30R18 can be expressed in inches as roughly 9.3 inches wide, 2.8 inches tall, and designed to fit a 18-inch wheel rim.

Frequently Asked Questions About 235/30R18 Tires

How tall is a 235/30R18 tire?

A 235/30R18 tire has an approximate height, also known as the overall diameter, of 23.6 inches (599 mm). This height can vary slightly depending on the brand and model of the tire, as well as the amount of air pressure in the tire.

How wide is a 235/30R18 tire?

A 235/30R18 tire has a width of approximately 9.3 inches (235 millimeters). The width of the tire is the first number in the tire size designation, which in this case is “235”. It’s important to note that the actual width of the tire may vary slightly depending on the brand and model of the tire, and the width may also be affected by the amount of air pressure in the tire.

Alternate 235/30R18 Replacement Tire Sizes

Upsizing your wheels or tires? Replacement tires must be within 3% of the diametor of the original tire. The following sizes fall within that range - click on any size to see detailed info about that tire and wheel combination.

SizeDiameterWidthWheel
125/60R1823.9"607 mm18 mm
125/70R1622.9"582 mm16 mm
125/70R1723.9"608 mm17 mm
125/80R1623.9"606 mm16 mm
125/90R1523.9"607 mm15 mm
135/70R1623.5"596 mm16 mm
135/80R1523.5"597 mm15 mm
135/90R1423.6"600 mm14 mm
145/80R1423.1"588 mm14 mm
155/65R1523"583 mm15 mm
155/70R1523.6"599 mm15 mm
155/80R1423.8"604 mm14 mm
165/40R1823.2"589 mm18 mm
165/65R1523.4"595 mm15 mm
165/70R1423.1"588 mm14 mm
165/80R1323.4"594 mm13 mm
175/45R1824.2"615 mm18 mm
175/50R1622.9"582 mm16 mm
175/55R1623.5"598 mm16 mm
175/60R1523.3"591 mm15 mm
175/60R1624.3"616 mm16 mm
175/65R1423"584 mm14 mm
175/65R1524"609 mm15 mm
175/70R1423.7"602 mm14 mm
175/80R1324"610 mm13 mm
185/50R1623.3"592 mm16 mm
185/55R1523"585 mm15 mm
185/55R1624"610 mm16 mm
185/60R1523.7"603 mm15 mm
185/65R1423.5"596 mm14 mm
185/70R1323.2"590 mm13 mm
185/70R1424.3"616 mm14 mm
195/35R1823.3"593 mm18 mm
195/40R1723.1"588 mm17 mm
195/45R1622.9"582 mm16 mm
195/45R1723.9"608 mm17 mm
195/50R1623.7"602 mm16 mm
195/55R1523.4"595 mm15 mm
195/60R1423.2"590 mm14 mm
195/60R1524.2"615 mm15 mm
195/65R1323"584 mm13 mm
195/65R1424"610 mm14 mm
195/70R1323.8"604 mm13 mm
205/35R1823.7"601 mm18 mm
205/40R1723.5"596 mm17 mm
205/45R1623.2"590 mm16 mm
205/45R1724.3"616 mm17 mm
205/50R1523.1"587 mm15 mm
205/50R1624.1"612 mm16 mm
205/55R1422.9"582 mm14 mm
205/55R1523.9"607 mm15 mm
205/60R1423.7"602 mm14 mm
215/35R1722.9"582 mm17 mm
215/35R1823.9"607 mm18 mm
215/40R1723.8"604 mm17 mm
215/45R1623.6"600 mm16 mm
215/50R1523.5"597 mm15 mm
215/60R1323.1"588 mm13 mm
215/60R1424.2"614 mm14 mm
225/30R1823.3"593 mm18 mm
225/35R1723.2"590 mm17 mm
225/35R1824.2"615 mm18 mm
225/40R1623.1"586 mm16 mm
225/40R1724.1"612 mm17 mm
225/45R1523"583 mm15 mm
225/45R1623.9"608 mm16 mm
225/50R1422.9"582 mm14 mm
225/50R1523.9"607 mm15 mm
225/55R1423.8"604 mm14 mm
235/30R1823.6"599 mm18 mm
235/45R1523.3"593 mm15 mm
235/60R1324.1"612 mm13 mm
245/30R1823.8"605 mm18 mm
245/35R1723.8"604 mm17 mm
245/50R1423.7"602 mm14 mm
255/30R1824.1"611 mm18 mm
255/35R1623"584 mm16 mm
255/45R1524.1"611 mm15 mm
285/40R1524"609 mm15 mm
295/35R1523.1"587 mm15 mm