315/45R21 In Inches – Tire Size & Rim Fitment Guide

What tire size is 315/45R21 in Inches?

The 315/45R21 tire has an overall diameter of 32.2 inches, a section width of 12.4 inches, and can be mounted on 21 inches height of rim. The equivalent tire size in the high flotation system is 32.2x12.4R21.

Tire Diameter32.2816.9
Section Width12.4315
Rim Height21533
Sidewall Height5.6141.8
tire diameter
Tire Side
Tire Circumference
627.1 Revs/Mile

For easy understanding, let us break down each component of the 315/45R21 tire size to know what these numbers represent and how they may affect your vehicle's performance:

How big is a 315/45R21 tire?

A 315/45R21 tire has a height of 32.2 inches (816.9 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.

Tire Diameter
Tire diameter: 32.2 In.

How wide is a 315/45R21 tire?

The 315/45R21 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.

You can put a slightly narrower or wider tire on a rim as long as it falls within the manufacturer's recommended tire width range.

tread width
Tread width: 12.4 In.

315/45R21 sidewall height

The 315/45R21 has a sidewall height of 5.6 inches (141.8 mm). It’s measured from the rim to the outer edge of the tire's tread, expressed as a percentage of tire width.

sidewall height
Sidewall height: 5.6 In.

What size rim do I need for 315/45R21 tire?

You can mount the 315/45R21 tire on a rim with a height of 21 inches.

Putting very narrow tires on wide rims or vice versa can result in reduced performance of the tire.

Rim Diameter
Rim height: 21 In.
rim width
Rim width: In.

315/45R21 circumference

The 315/45R21 tire has a circumference of 101 inches (2566.4 mm), This is the measurement of the distance the tire travels in one revolution.

The tire circumference plays a crucial role in your vehicle's overall performance, affecting its speedometer acceleration, accuracy and fuel efficiency.

Circumference: 101 In.

315/45R21 Revolutions

The 315/45R21 performs 627.1 revs/mile. Revolutions per mile indicate the number of times a tire rotates while it covers the distance of one mile.

627.1 revs/mile

Compatible Tire Sizes for 315/45R21

As a rule, you can replace the tire within a 3% difference in tire diameter (height) of the OEM tire size. However, it should be considered as a general guideline, not a hard and fast rule. Here is a list of compatible tire sizes for 315/45R21:

Tire SizeDiameterRim (H x W)
275/60R2033″ (+2.4%)20″ x 7.5-9.5″
285/40R2433″ (+2.4%)24″ x 9.5-11.0″
295/30R2633″ (+2.4%)26″ x 10.0-11.0″
275/55R2132.9″ (+2.1%)21″ x 7.5-9.5″
295/55R2032.8″ (+1.8%)20″ x 8.0-10.0″
325/50R2032.8″ (+1.8%)20″ x 9.0-11.5″
275/50R2232.8″ (+1.8%)22″ x 7.5-9.5″
305/45R2232.8″ (+1.8%)22″ x 9.5-11.5″
315/35R2432.7″ (+1.5%)24″ x 10.5-12.5″
305/40R2332.6″ (+1.2%)23″ x 10.0-12.0″
265/60R2032.5″ (+0.9%)20″ x 7.5-9.5″
295/45R2232.5″ (+0.9%)22″ x 9.5-11.0″
315/50R2032.4″ (+0.6%)20″ x 8.5-11.0″
265/50R2232.4″ (+0.6%)22″ x 7.5-9.5″
305/35R2432.4″ (+0.6%)24″ x 10.0-12.0″
285/55R2032.3″ (+0.3%)20″ x 8.0-10.0″
325/40R2232.2″ (Equal)22″ x 11.0-13.0″
285/45R2232.1″ (-0.3%)22″ x 9.0-10.5″
295/35R2432.1″ (-0.3%)24″ x 10.0-11.5″
255/60R2032″ (-0.6%)20″ x 7.0-9.0″
305/50R2032″ (-0.6%)20″ x 8.5-11.0″
285/40R2332″ (-0.6%)23″ x 9.5.0-11.0″
325/35R2332″ (-0.6%)23″ x n/a
405/25R2432″ (-0.6%)24″ x 14.0-15.0″
255/30R2632″ (-0.6%)26″ x 8.5-9.5″
305/25R2632″ (-0.6%)26″ x 10.5-11.5″
275/55R2031.9″ (-0.9%)20″ x 7.5-9.5″
285/35R2431.9″ (-0.9%)24″ x 9.5-11.0″
335/30R2431.9″ (-0.9%)24″ x n/a
275/50R2131.8″ (-1.3%)21″ x 7.5-9.5″
295/25R2631.8″ (-1.3%)26″ x 10.0-11.0″
275/45R2231.7″ (-1.6%)22″ x 8.5-10.5″
275/40R2331.7″ (-1.6%)23″ x 9.0-11.0″
245/60R2031.6″ (-1.9%)20″ x 7.0-8.5″
295/50R2031.6″ (-1.9%)20″ x 8.0-10.5″
305/40R2231.6″ (-1.9%)22″ x 10.0-12.0″
265/55R2031.5″ (-2.2%)20″ x n/a
265/45R2231.4″ (-2.5%)22″ x 8.5-10.0″
305/35R2331.4″ (-2.5%)23″ x 10.0-12.0″
315/30R2431.4″ (-2.5%)24″ x 10.5-11.5″
275/25R2631.4″ (-2.5%)26″ x 10.0″
295/40R2231.3″ (-2.9%)22″ x 10.0-11.5″

*Disclaimer: The tire size is for information purposes only, the measurement is an approximation, as tire manufacturers can have slight variations in their measurements. It's recommended to refer to the vehicle manufacturer's guidelines or consult with a tire mechanic to determine the correct tire size for your vehicle.

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More tire sizes for 21" Wheel:

26″ Tire Diameter

27″ Tire Diameter

28″ Tire Diameter

29″ Tire Diameter

30″ Tire Diameter

31″ Tire Diameter

32″ Tire Diameter

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