145/70R12 Tire Size in Inches and Millimeters
145/70R12 tires have a diameter of 20" (509 mm), a tread width of 5.7" (145 mm), and a wheel diameter of 12" (304.8 mm).The sidewall of the tire is 4" (102 mm), and the tire's circumference is 62.8" (1598.3 mm). This means a 145/70R12 tire will make make 1009 revolutions per mile, or 626 revolutions per kilometer.
| Spec | Inches | Metric |
|---|---|---|
| Diameter | 20" | 509 mm |
| Width | 5.7" | 145 mm |
| Wheel | 12" | 304.8 mm |
| Sidewall | 4" | 102 mm |
| Circum | 62.8" | 1598.3 mm |
| Revolutions | 1009 per mile | 626 per km |
What Does 145/70R12 Mean?
The tire size 145/70R12 is a common size used on many trucks, SUVs, and other larger vehicles.
Here is what each part of the size designation represents:
- 145: This number represents the width of the tire in millimeters. In this case, the tire is 145 millimeters wide.
- 70: 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 70% 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.
- 12: 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 12-inch wheel.
How To Convert 145/70R12 Into Inches
The 145/70R12 conversion is fairly simple. The first number in the tire size, 145, represents the width of the tire in millimeters. To convert this to inches, we divide 145 by 25.4 (since there are 25.4 millimeters in an inch). This gives us approximately 5.7 inches.
The second number in the tire size, 70, represents the aspect ratio or the height of the tire as a percentage of its width. To calculate the height in inches, we multiply 5.7 by 0.70, which gives us approximately 4 inches.
Finally, the last number in the tire size, 12, represents the diameter of the wheel rim in inches. Therefore, the tire size 145/70R12 can be expressed in inches as roughly 5.7 inches wide, 4 inches tall, and designed to fit a 12-inch wheel rim.
Frequently Asked Questions About 145/70R12 Tires
How tall is a 145/70R12 tire?
A 145/70R12 tire has an approximate height, also known as the overall diameter, of 20 inches (509 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 145/70R12 tire?
A 145/70R12 tire has a width of approximately 5.7 inches (145 millimeters). The width of the tire is the first number in the tire size designation, which in this case is “145”. 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 145/70R12 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.
| Size | Diameter | Width | Wheel |
|---|---|---|---|
| 105/70R14 | 19.8" | 504 mm | 14 mm |
| 105/80R13 | 19.6" | 498 mm | 13 mm |
| 115/70R14 | 20.4" | 518 mm | 14 mm |
| 125/80R12 | 19.9" | 505 mm | 12 mm |
| 135/70R13 | 20.5" | 520 mm | 13 mm |
| 135/80R12 | 20.5" | 521 mm | 12 mm |
| 145/60R13 | 19.8" | 504 mm | 13 mm |
| 145/65R13 | 20.4" | 518 mm | 13 mm |
| 145/70R12 | 20" | 509 mm | 12 mm |
| 155/70R12 | 20.6" | 523 mm | 12 mm |
| 155/80R10 | 19.8" | 502 mm | 10 mm |
| 165/50R14 | 20.6" | 522 mm | 14 mm |
| 165/55R13 | 20.2" | 512 mm | 13 mm |
| 165/60R12 | 19.8" | 503 mm | 12 mm |
| 175/50R13 | 19.9" | 506 mm | 13 mm |
| 175/55R13 | 20.6" | 522 mm | 13 mm |
| 195/40R14 | 20.2" | 512 mm | 14 mm |
| 195/45R13 | 19.9" | 506 mm | 13 mm |