325/45R21 tire size in inches
A 325/45R21 tire measures
32.5" tall × 12.8" wide
5.76" sidewall on a 21" wheel. 620 revolutions per mile.
325/45R21 means a tire 325 mm wide, with sidewalls 45% as tall as the tire is wide (146 mm), radial construction (R), for a 21 inch wheel.
325/45R21 specs
| Overall diameter (height) | 32.52 inches (826 mm) |
|---|---|
| Section width | 12.80 inches (325 mm) |
| Sidewall height | 5.76 inches (146 mm) |
| Wheel (rim) diameter | 21 inches |
| Circumference | 102.2 inches (2,595 mm) |
| Revolutions per mile | 620 |
| Revolutions per kilometer | 385 |
| Approximate rim width | 10.5" to 12.0" |
| In inches (flotation style) | 32.5x12.8R21 |
| Aspect ratio | 45% |
Calculated from the size. Real tires differ by brand, model and tread depth, typically by a few tenths of an inch.
Sizes that can replace 325/45R21 on a 21" wheel
These 21" sizes are within 3% of 325/45R21's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 265/55R21 | 32.48" | 10.43" | −0.1% | 59.9 mph | Compare |
| 295/50R21 | 32.61" | 11.61" | +0.3% | 60.2 mph | Compare |
| 285/50R21 | 32.22" | 11.22" | −0.9% | 59.5 mph | Compare |
| 355/40R21 | 32.18" | 13.98" | −1.0% | 59.4 mph | Compare |
| 315/45R21 | 32.16" | 12.40" | −1.1% | 59.3 mph | Compare |
| 335/45R21 | 32.87" | 13.19" | +1.1% | 60.7 mph | Compare |
| 275/55R21 | 32.91" | 10.83" | +1.2% | 60.7 mph | Compare |
| 255/55R21 | 32.04" | 10.04" | −1.5% | 59.1 mph | Compare |
| 305/50R21 | 33.01" | 12.01" | +1.5% | 60.9 mph | Compare |
| 345/40R21 | 31.87" | 13.58" | −2.0% | 58.8 mph | Compare |
| 275/50R21 | 31.83" | 10.83" | −2.1% | 58.7 mph | Compare |
| 305/45R21 | 31.81" | 12.01" | −2.2% | 58.7 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 265/60R20 | 20" | 32.52" | 0.0% | Compare |
| 335/55R18 | 18" | 32.51" | 0.0% | Compare |
| 245/65R20 | 20" | 32.54" | +0.1% | Compare |
| 335/40R22 | 22" | 32.55" | +0.1% | Compare |
| 245/75R18 | 18" | 32.47" | −0.1% | Compare |
| 265/65R19 | 19" | 32.56" | +0.1% | Compare |
| 285/60R19 | 19" | 32.46" | −0.2% | Compare |
| 295/45R22 | 22" | 32.45" | −0.2% | Compare |
| 355/45R20 | 20" | 32.58" | +0.2% | Compare |
| 345/50R19 | 19" | 32.58" | +0.2% | Compare |
| 285/65R18 | 18" | 32.59" | +0.2% | Compare |
| 265/50R22 | 22" | 32.43" | −0.3% | Compare |
One size up or down
- 315/45R21narrower: 32.2" × 12.4"
- 335/45R21wider: 32.9" × 13.2"
- 325/40R21lower profile: 31.2" × 12.8"
- 325/50R21taller sidewall: 33.8" × 12.8"
Compare 325/45R21 with another size
Questions
- How tall is a 325/45R21 tire?
- A 325/45R21 tire is 32.5 inches tall (826 mm), calculated from the size. It is 12.8 inches wide with 5.8 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 325/45R21 mean?
- 325/45R21 means a tire 325 mm wide, with sidewalls 45% as tall as the tire is wide (146 mm), radial construction (R), for a 21 inch wheel.
- How many revolutions per mile does a 325/45R21 tire make?
- About 620 revolutions per mile, based on a circumference of 102.2 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 325/45R21 tire?
- Roughly 10.5" to 12.0". Check the tire maker's approved rim range for the exact model before buying wheels.
- Can I use 265/55R21 instead of 325/45R21?
- 265/55R21 is −0.04 inches (−0.1%) in overall diameter, so at an indicated 60 mph you would be doing 59.9 mph. Differences under 3% are usually fine, but check clearance, load index and your vehicle's placard.