235/45R21 Tire Size in Inches and Millimeters
235/45R21 tires have a diameter of 29.3" (745 mm), a tread width of 9.3" (235 mm), and a wheel diameter of 21" (533.4 mm).The sidewall of the tire is 4.2" (106 mm), and the tire's circumference is 92" (2339.3 mm). This means a 235/45R21 tire will make make 689 revolutions per mile, or 427 revolutions per kilometer.
| Spec | Inches | Metric |
|---|---|---|
| Diameter | 29.3" | 745 mm |
| Width | 9.3" | 235 mm |
| Wheel | 21" | 533.4 mm |
| Sidewall | 4.2" | 106 mm |
| Circum | 92" | 2339.3 mm |
| Revolutions | 689 per mile | 427 per km |
What Does 235/45R21 Mean?
The tire size 235/45R21 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.
- 21: 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 21-inch wheel.
How To Convert 235/45R21 Into Inches
The 235/45R21 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, 21, represents the diameter of the wheel rim in inches. Therefore, the tire size 235/45R21 can be expressed in inches as roughly 9.3 inches wide, 4.2 inches tall, and designed to fit a 21-inch wheel rim.
Frequently Asked Questions About 235/45R21 Tires
How tall is a 235/45R21 tire?
A 235/45R21 tire has an approximate height, also known as the overall diameter, of 29.3 inches (745 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 235/45R21 tire?
A 235/45R21 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.Alternate 235/45R21 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 |
|---|---|---|---|
| 145/80R20 | 29.1" | 740 mm | 20 mm |
| 155/80R19 | 28.8" | 731 mm | 19 mm |
| 155/90R18 | 29" | 737 mm | 18 mm |
| 165/90R17 | 28.7" | 730 mm | 17 mm |
| 165/90R18 | 29.7" | 755 mm | 18 mm |
| 175/80R18 | 29" | 737 mm | 18 mm |
| 175/80R19 | 30" | 763 mm | 19 mm |
| 175/90R17 | 29.4" | 748 mm | 17 mm |
| 205/80R16 | 28.9" | 734 mm | 16 mm |
| 205/90R15 | 29.6" | 751 mm | 15 mm |
| 215/70R17 | 28.9" | 734 mm | 17 mm |
| 215/75R16 | 28.7" | 728 mm | 16 mm |
| 215/80R15 | 28.5" | 725 mm | 15 mm |
| 215/80R16 | 29.5" | 750 mm | 16 mm |
| 215/85R15 | 29.4" | 747 mm | 15 mm |
| 225/55R19 | 28.8" | 731 mm | 19 mm |
| 225/60R18 | 28.6" | 727 mm | 18 mm |
| 225/65R17 | 28.5" | 724 mm | 17 mm |
| 225/65R18 | 29.5" | 749 mm | 18 mm |
| 225/70R17 | 29.4" | 748 mm | 17 mm |
| 225/75R16 | 29.3" | 744 mm | 16 mm |
| 225/80R15 | 29.2" | 741 mm | 15 mm |
| 235/45R21 | 29.3" | 745 mm | 21 mm |
| 235/50R20 | 29.3" | 744 mm | 20 mm |
| 235/55R19 | 29.2" | 741 mm | 19 mm |
| 235/55R20 | 30.2" | 766 mm | 20 mm |
| 235/60R18 | 29.1" | 739 mm | 18 mm |
| 235/60R19 | 30.1" | 765 mm | 19 mm |
| 235/65R17 | 29.1" | 738 mm | 17 mm |
| 235/65R18 | 30" | 763 mm | 18 mm |
| 235/70R16 | 29" | 736 mm | 16 mm |
| 235/70R17 | 30" | 762 mm | 17 mm |
| 235/75R15 | 28.9" | 733 mm | 15 mm |
| 235/75R16 | 29.8" | 758 mm | 16 mm |
| 235/80R15 | 29.8" | 757 mm | 15 mm |
| 245/25R24 | 28.8" | 732 mm | 24 mm |
| 245/30R24 | 29.8" | 758 mm | 24 mm |
| 245/35R22 | 28.8" | 731 mm | 22 mm |
| 245/40R21 | 28.7" | 729 mm | 21 mm |
| 245/45R20 | 28.7" | 728 mm | 20 mm |
| 245/45R21 | 29.6" | 753 mm | 21 mm |
| 245/50R19 | 28.7" | 729 mm | 19 mm |
| 245/50R20 | 29.7" | 754 mm | 20 mm |
| 245/55R18 | 28.6" | 727 mm | 18 mm |
| 245/55R19 | 29.6" | 753 mm | 19 mm |
| 245/60R17 | 28.6" | 726 mm | 17 mm |
| 245/60R18 | 29.6" | 751 mm | 18 mm |
| 245/65R17 | 29.5" | 750 mm | 17 mm |
| 245/70R15 | 28.5" | 725 mm | 15 mm |
| 245/70R16 | 29.5" | 750 mm | 16 mm |
| 245/75R15 | 29.5" | 749 mm | 15 mm |
| 247/70R16 | 29.6" | 752 mm | 16 mm |
| 255/25R24 | 29.1" | 738 mm | 24 mm |
| 255/30R24 | 30.1" | 764 mm | 24 mm |
| 255/35R22 | 29" | 737 mm | 22 mm |
| 255/40R21 | 29" | 737 mm | 21 mm |
| 255/40R22 | 30" | 763 mm | 22 mm |
| 255/45R20 | 29.1" | 738 mm | 20 mm |
| 255/45R21 | 30" | 763 mm | 21 mm |
| 255/50R19 | 29.1" | 739 mm | 19 mm |
| 255/50R20 | 30.1" | 764 mm | 20 mm |
| 255/55R18 | 29" | 737 mm | 18 mm |
| 255/55R19 | 30" | 763 mm | 19 mm |
| 255/60R17 | 29.1" | 738 mm | 17 mm |
| 255/60R18 | 30" | 763 mm | 18 mm |
| 255/65R16 | 29.1" | 738 mm | 16 mm |
| 255/65R17 | 30.1" | 764 mm | 17 mm |
| 255/70R15 | 29.1" | 739 mm | 15 mm |
| 255/70R16 | 30.1" | 764 mm | 16 mm |
| 255/75R15 | 30" | 763 mm | 15 mm |
| 265/25R24 | 29.2" | 742 mm | 24 mm |
| 265/35R22 | 29.3" | 745 mm | 22 mm |
| 265/40R21 | 29.3" | 745 mm | 21 mm |
| 265/45R20 | 29.4" | 746 mm | 20 mm |
| 265/50R18 | 28.5" | 723 mm | 18 mm |
| 265/50R19 | 29.5" | 749 mm | 19 mm |
| 265/55R17 | 28.5" | 724 mm | 17 mm |
| 265/55R18 | 29.5" | 749 mm | 18 mm |
| 265/60R16 | 28.5" | 724 mm | 16 mm |
| 265/60R17 | 29.5" | 750 mm | 17 mm |
| 265/65R16 | 29.5" | 750 mm | 16 mm |
| 265/70R15 | 29.6" | 753 mm | 15 mm |
| 275/23R24 | 29" | 736 mm | 24 mm |
| 275/25R24 | 29.4" | 748 mm | 24 mm |
| 275/30R22 | 28.5" | 725 mm | 22 mm |
| 275/35R21 | 28.5" | 725 mm | 21 mm |
| 275/35R22 | 29.6" | 751 mm | 22 mm |
| 275/40R20 | 28.7" | 728 mm | 20 mm |
| 275/40R21 | 29.6" | 753 mm | 21 mm |
| 275/45R19 | 28.8" | 731 mm | 19 mm |
| 275/45R20 | 29.8" | 756 mm | 20 mm |
| 275/50R18 | 28.9" | 733 mm | 18 mm |
| 275/50R19 | 29.9" | 759 mm | 19 mm |
| 275/55R17 | 28.9" | 734 mm | 17 mm |
| 275/55R18 | 29.9" | 759 mm | 18 mm |
| 275/60R16 | 29" | 736 mm | 16 mm |
| 275/60R17 | 30" | 762 mm | 17 mm |
| 275/65R16 | 30.1" | 764 mm | 16 mm |
| 275/70R15 | 30.2" | 767 mm | 15 mm |
| 285/30R22 | 28.8" | 731 mm | 22 mm |
| 285/35R21 | 28.9" | 733 mm | 21 mm |
| 285/35R22 | 29.9" | 759 mm | 22 mm |
| 285/40R20 | 29" | 736 mm | 20 mm |
| 285/40R21 | 30" | 761 mm | 21 mm |
| 285/45R19 | 29.1" | 739 mm | 19 mm |
| 285/45R20 | 30.1" | 764 mm | 20 mm |
| 285/50R18 | 29.3" | 743 mm | 18 mm |
| 285/60R16 | 29.4" | 748 mm | 16 mm |
| 295/23R24 | 29.4" | 746 mm | 24 mm |
| 295/30R22 | 29" | 737 mm | 22 mm |
| 295/30R23 | 30" | 762 mm | 23 mm |
| 295/35R21 | 29.1" | 739 mm | 21 mm |
| 295/35R22 | 30.1" | 765 mm | 22 mm |
| 295/40R20 | 29.3" | 744 mm | 20 mm |
| 295/45R18 | 28.5" | 723 mm | 18 mm |
| 295/45R19 | 29.5" | 749 mm | 19 mm |
| 295/60R15 | 28.9" | 735 mm | 15 mm |
| 295/65R15 | 30.1" | 765 mm | 15 mm |
| 305/25R23 | 29" | 736 mm | 23 mm |
| 305/30R22 | 29.3" | 743 mm | 22 mm |
| 305/35R21 | 29.4" | 747 mm | 21 mm |
| 305/40R20 | 29.6" | 752 mm | 20 mm |
| 305/45R18 | 28.8" | 731 mm | 18 mm |
| 315/25R23 | 29.2" | 742 mm | 23 mm |
| 315/30R21 | 28.5" | 723 mm | 21 mm |
| 315/30R22 | 29.5" | 749 mm | 22 mm |
| 315/35R20 | 28.7" | 728 mm | 20 mm |
| 315/35R21 | 29.6" | 753 mm | 21 mm |
| 315/40R19 | 28.9" | 735 mm | 19 mm |
| 315/55R16 | 29.6" | 752 mm | 16 mm |
| 315/60R15 | 29.9" | 759 mm | 15 mm |
| 325/30R21 | 28.7" | 729 mm | 21 mm |
| 325/35R20 | 29" | 736 mm | 20 mm |
| 325/45R18 | 29.5" | 749 mm | 18 mm |
| 335/25R22 | 28.6" | 727 mm | 22 mm |
| 345/35R19 | 28.5" | 725 mm | 19 mm |
| 345/55R15 | 30" | 761 mm | 15 mm |