| Tire Size | Diameter | Rim (H x W) |
| 275/50R21 | 31.8″ (+2.8%) | 21″ x 7.5-9.5″ |
| 295/25R26 | 31.8″ (+2.8%) | 26″ x 10.0-11.0″ |
| 275/45R22 | 31.7″ (+2.5%) | 22″ x 8.5-10.5″ |
| 275/40R23 | 31.7″ (+2.5%) | 23″ x 9.0-11.0″ |
| 245/60R20 | 31.6″ (+2.2%) | 20″ x 7.0-8.5″ |
| 295/50R20 | 31.6″ (+2.2%) | 20″ x 8.0-10.5″ |
| 305/40R22 | 31.6″ (+2.2%) | 22″ x 10.0-12.0″ |
| 265/55R20 | 31.5″ (+1.9%) | 20″ x n/a |
| 265/45R22 | 31.4″ (+1.6%) | 22″ x 8.5-10.0″ |
| 305/35R23 | 31.4″ (+1.6%) | 23″ x 10.0-12.0″ |
| 315/30R24 | 31.4″ (+1.6%) | 24″ x 10.5-11.5″ |
| 275/25R26 | 31.4″ (+1.6%) | 26″ x 10.0″ |
| 295/40R22 | 31.3″ (+1.3%) | 22″ x 10.0-11.5″ |
| 285/50R20 | 31.2″ (+1%) | 20″ x 8.0-10.0″ |
| 325/40R21 | 31.2″ (+1%) | 21″ x 11.0-13.0″ |
| 235/60R20 | 31.1″ (+0.6%) | 20″ x 6.5-8.5″ |
| 285/45R21 | 31.1″ (+0.6%) | 21″ x 9.0-10.5″ |
| 295/35R23 | 31.1″ (+0.6%) | 23″ x 10.0-11.5″ |
| 255/55R20 | 31″ (+0.3%) | 20″ x 7.0-9.0″ |
| 255/50R21 | 31″ (+0.3%) | 21″ x 7.0-9.0″ |
| 255/45R22 | 31″ (+0.3%) | 22″ x 8.0-9.5″ |
| 285/40R22 | 31″ (+0.3%) | 22″ x 9.5-11.0″ |
| 325/35R22 | 31″ (+0.3%) | 22″ x 11.0-13.0″ |
| 295/30R24 | 31″ (+0.3%) | 24″ x 10.0-11.0″ |
| 355/25R24 | 31″ (+0.3%) | 24″ x n/a |
| 285/35R23 | 30.9″ (Equal) | 23″ x 9.5-11.0″ |
| 275/50R20 | 30.8″ (-0.3%) | 20″ x 7.5-9.5″ |
| 305/45R20 | 30.8″ (-0.3%) | 20″ x 9.5-11.5″ |
| 275/45R21 | 30.7″ (-0.7%) | 21″ x 8.5-10.5″ |
| 275/40R22 | 30.7″ (-0.7%) | 22″ x 9.0-11.0″ |
| 315/35R22 | 30.7″ (-0.7%) | 22″ x 10.5-12.5″ |
| 325/30R23 | 30.7″ (-0.7%) | 23″ x n/a |
| 285/30R24 | 30.7″ (-0.7%) | 24″ x 9.5-10.5″ |
| 295/45R20 | 30.5″ (-1.3%) | 20″ x 9.5-11.0″ |
| 275/30R24 | 30.5″ (-1.3%) | 24″ x 9.0-10.0″ |
| 265/50R20 | 30.4″ (-1.6%) | 20″ x 7.5-9.5″ |
| 265/45R21 | 30.4″ (-1.6%) | 21″ x 8.5-10.0″ |
| 305/35R22 | 30.4″ (-1.6%) | 22″ x 10.0-12.0″ |
| 295/40R21 | 30.3″ (-2%) | 21″ x 10.0-11.5″ |
| 265/40R22 | 30.3″ (-2%) | 22″ x 9.0-10.5″ |
| 235/55R20 | 30.2″ (-2.3%) | 20″ x 6.5-8.5″ |
| 285/45R20 | 30.1″ (-2.7%) | 20″ x 9.0-10.5″ |
| 295/35R22 | 30.1″ (-2.7%) | 22″ x 10.0-11.5″ |
| 255/50R20 | 30″ (-3%) | 20″ x 7.0-9.0″ |
| 255/45R21 | 30″ (-3%) | 21″ x 9.5-11.0″ |
| 285/40R21 | 30″ (-3%) | 21″ x 9.5-11.0″ |
| 255/40R22 | 30″ (-3%) | 22″ x 8.5-10.0″ |
| 295/30R23 | 30″ (-3%) | 23″ x 10.0-11.0″ |
| 255/30R24 | 30″ (-3%) | 24″ x 8.5-9.5″ |
315/40R21 In Inches – Tire Size & Wheel Fitment Guide
What size tire is 315/40R21 in Inches?
The 315/40R21 tire has an overall diameter of 30.9 inches, a section width of 12.4 inches, and can be mounted on 21 x 10.5-12.5 inches rim. The equivalent tire size in the high flotation system is 30.9x12.4R21.
| Inches | Millimeters | |
| Tire Diameter | 30.9 | 785.4 |
| Section Width | 12.4 | 315 |
| Rim Height | 21 | 533 |
| Sidewall Height | 5 | 126 |
| Circumference | 97.1 | 2467.4 |
12.4"
30.9"
97.1"
21"
5"
652.2 Revs/Mile
To help you understand, we'll break down each part of the 315/40R21 tire size to know what these numbers represent & how they may affect your tire's performance:
How wide is a 315/40R21 tire?
The 315/40R21 tire has a width of 12.4 inches (315 mm). This is the measurement at its thickest point, the distance between the outer sidewall and the inner sidewall’s widest point, also called as tread width or section width.
How tall is a 315/40R21 tire?
The 315/40R21 tire has a height of 30.9 inches (785.4 mm). This is the measurement from the bottom to the highest point at the top of a tire through its exact center when inflated and unloaded.
315/40R21 sidewall height
The 315/40R21 has a sidewall height of 5 inches (126 mm). It’s measured from the rim to the outer edge of the tire's tread, expressed as a percentage of tire width.
What size rim do you need for 315/40R21 tire?
You can mount the 315/40R21 tire on a rim with a height of 21 inches and a width ranging from 10.5-12.5 inches. (Based on recommendations of The Tire and Rim Association (TRA))
Putting very narrow tires on wide rims or vice versa can result in reduced performance of the tire.
315/40R21 circumference
The 315/40R21 tire has a circumference of 97.1 inches (2467.4 mm), This is the measurement of the distance the tire travels in one revolution.
The tire circumference is important for your vehicle's overall performance, affecting its speedometer acceleration, accuracy and fuel efficiency.
315/40R21 Revolutions
The 315/40R21 performs 652.2 revs/mile. Revolutions per mile indicate the number of times a tire rotates while it covers the distance of one mile.
Replacement Tire Sizes for 315/40R21
As a rule, you can replace the tire within a 3% difference in tire diameter (height) of the OEM tire size. Here is a list of compatible tire sizes for 315/40R21:
*Disclaimer: Please note that our tire dimensions & measurements are an approximation number, while the tire manufacturers may have different ways in calculating or rounding numbers. We recommend referring to the vehicle manufacturer's manual or checking with the tire technician to find out the correct tire size for your vehicle.