325/75R20 Tire Size in Inches and Millimeters
325/75R20 tires have a diameter of 39.2" (996 mm), a tread width of 12.8" (325 mm), and a wheel diameter of 20" (508 mm).The sidewall of the tire is 9.6" (244 mm), and the tire's circumference is 123.1" (3127.4 mm). This means a 325/75R20 tire will make make 515 revolutions per mile, or 320 revolutions per kilometer.
| Spec | Inches | Metric |
|---|---|---|
| Diameter | 39.2" | 996 mm |
| Width | 12.8" | 325 mm |
| Wheel | 20" | 508 mm |
| Sidewall | 9.6" | 244 mm |
| Circum | 123.1" | 3127.4 mm |
| Revolutions | 515 per mile | 320 per km |
What Does 325/75R20 Mean?
The tire size 325/75R20 is a common size used on many trucks, SUVs, and other larger vehicles.
Here is what each part of the size designation represents:
- 325: This number represents the width of the tire in millimeters. In this case, the tire is 325 millimeters wide.
- 75: 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 75% 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.
- 20: 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 20-inch wheel.
How To Convert 325/75R20 Into Inches
The 325/75R20 conversion is fairly simple. The first number in the tire size, 325, represents the width of the tire in millimeters. To convert this to inches, we divide 325 by 25.4 (since there are 25.4 millimeters in an inch). This gives us approximately 12.8 inches.
The second number in the tire size, 75, represents the aspect ratio or the height of the tire as a percentage of its width. To calculate the height in inches, we multiply 12.8 by 0.75, which gives us approximately 9.6 inches.
Finally, the last number in the tire size, 20, represents the diameter of the wheel rim in inches. Therefore, the tire size 325/75R20 can be expressed in inches as roughly 12.8 inches wide, 9.6 inches tall, and designed to fit a 20-inch wheel rim.
Frequently Asked Questions About 325/75R20 Tires
How tall is a 325/75R20 tire?
A 325/75R20 tire has an approximate height, also known as the overall diameter, of 39.2 inches (996 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 325/75R20 tire?
A 325/75R20 tire has a width of approximately 12.8 inches (325 millimeters). The width of the tire is the first number in the tire size designation, which in this case is “325”. 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
- P-Rated: Up to 94 mph - Suitable for smaller sedans or light-duty vehicles.
- Q-Rated: Up to 100 mph - Often found on SUVs and light trucks with consistent highway use.
- R-Rated: Up to 106 mph - Typically for medium-duty trucks and vans.
- S-Rated: Up to 112 mph - Common for family sedans and larger vehicles with moderate performance.
- 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.
Alternate 325/75R20 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.