235/45R15 Tire Size in Inches and Millimeters

235/45R15 tires have a diameter of 23.3" (593 mm), a tread width of 9.3" (235 mm), and a wheel diameter of 15" (381 mm).The sidewall of the tire is 4.2" (106 mm), and the tire's circumference is 73.2" (1862 mm). This means a 235/45R15 tire will make make 866 revolutions per mile, or 537 revolutions per kilometer.

235/45R15 Tire Front
9.3"
23.3"
235/45R15 Tire Side
Tire Circumference
73.2"
15"
4.2"
866 Revs/Mile
SpecInchesMetric
Diameter23.3"593 mm
Width9.3"235 mm
Wheel15"381 mm
Sidewall4.2"106 mm
Circum73.2"1862 mm
Revolutions866 per mile537 per km

What Does 235/45R15 Mean?

The tire size 235/45R15 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.
  • 45: 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 45% 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.
  • 15: 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 15-inch wheel.

235/45R15 tire size meaning

How To Convert 235/45R15 Into Inches

The 235/45R15 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, 45, 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 0.45, which gives us approximately 4.2 inches.

Finally, the last number in the tire size, 15, represents the diameter of the wheel rim in inches. Therefore, the tire size 235/45R15 can be expressed in inches as roughly 9.3 inches wide, 4.2 inches tall, and designed to fit a 15-inch wheel rim.

Frequently Asked Questions About 235/45R15 Tires

How tall is a 235/45R15 tire?

A 235/45R15 tire has an approximate height, also known as the overall diameter, of 23.3 inches (593 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 235/45R15 tire?

A 235/45R15 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.

Understanding Tire Speed Ratings

When choosing the right tires for your vehicle, understanding the speed rating is crucial. But what exactly is a speed rating, and why does it matter?

What is a Tire Speed Rating?

A tire's speed rating indicates the maximum speed a tire can safely sustain over time. It's a manufacturer's assurance of tire performance, marked by a letter on the tire's sidewall. This rating is determined under controlled laboratory conditions and is part of a broader standard established by industry entities like the European Tyre and Rim Technical Organisation (ETRTO) and the U.S. Department of Transportation.

Common Speed Ratings Explained

  1. P-Rated: Up to 94 mph - Suitable for smaller sedans or light-duty vehicles.
  2. Q-Rated: Up to 100 mph - Often found on SUVs and light trucks with consistent highway use.
  3. R-Rated: Up to 106 mph - Typically for medium-duty trucks and vans.
  4. S-Rated: Up to 112 mph - Common for family sedans and larger vehicles with moderate performance.
  5. T-Rated: Up to 118 mph - Optimal for family vehicles, including minivans and some coupes.

Why is the Speed Rating Important?

The speed rating is not just about how fast you can legally drive; it's about safety and performance:
  • Ensures Safety: It guarantees that the tire can handle certain speeds without overheating and failing, which can prevent blowouts.
  • Optimizes Performance: Higher ratings often indicate better handling characteristics, important for maintaining vehicle stability.
  • Legal and Insurance Considerations: Matching the speed rating suggested by your vehicle manufacturer can be essential for insurance and warranty purposes.
When choosing tires, always refer to your vehicle’s manual to ensure compatibility. Remember, fitting tires with a lower speed rating than recommended can compromise safety and performance, while higher ratings might not provide extra benefits unless you frequently drive at high speeds. By understanding these nuances, you can make an informed choice that suits your driving habits while keeping safety a top priority.

Alternate 235/45R15 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
125/80R1522.9"581 mm15 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
155/80R1322.8"578 mm13 mm
155/80R1423.8"604 mm14 mm
165/40R1823.2"589 mm18 mm
165/45R1722.8"580 mm17 mm
165/60R1522.8"579 mm15 mm
165/65R1523.4"595 mm15 mm
165/70R1423.1"588 mm14 mm
165/75R1322.8"578 mm13 mm
165/80R1323.4"594 mm13 mm
175/50R1622.9"582 mm16 mm
175/55R1623.5"598 mm16 mm
175/60R1523.3"591 mm15 mm
175/65R1423"584 mm14 mm
175/65R1524"609 mm15 mm
175/70R1322.7"576 mm13 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
185/60R1422.8"578 mm14 mm
185/60R1523.7"603 mm15 mm
185/65R1423.5"596 mm14 mm
185/70R1323.2"590 mm13 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
195/50R1522.7"577 mm15 mm
195/50R1623.7"602 mm16 mm
195/55R1523.4"595 mm15 mm
195/60R1423.2"590 mm14 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
205/50R1523.1"587 mm15 mm
205/55R1422.9"582 mm14 mm
205/55R1523.9"607 mm15 mm
205/60R1322.7"576 mm13 mm
205/60R1423.7"602 mm14 mm
215/35R1722.9"582 mm17 mm
215/35R1823.9"607 mm18 mm
215/40R1622.8"578 mm16 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
225/30R1823.3"593 mm18 mm
225/35R1723.2"590 mm17 mm
225/40R1623.1"586 mm16 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
245/30R1823.8"605 mm18 mm
245/35R1622.8"578 mm16 mm
245/35R1723.8"604 mm17 mm
245/40R1522.7"577 mm15 mm
245/50R1322.7"576 mm13 mm
245/50R1423.7"602 mm14 mm
255/35R1623"584 mm16 mm
285/40R1524"609 mm15 mm
295/35R1523.1"587 mm15 mm