345/45R21 tire size in inches
A 345/45R21 tire measures
33.2" tall × 13.6" wide
6.11" sidewall on a 21" wheel. 607 revolutions per mile.
345/45R21 means a tire 345 mm wide, with sidewalls 45% as tall as the tire is wide (155 mm), radial construction (R), for a 21 inch wheel.
345/45R21 specs
| Overall diameter (height) | 33.22 inches (844 mm) |
|---|---|
| Section width | 13.58 inches (345 mm) |
| Sidewall height | 6.11 inches (155 mm) |
| Wheel (rim) diameter | 21 inches |
| Circumference | 104.4 inches (2,651 mm) |
| Revolutions per mile | 607 |
| Revolutions per kilometer | 377 |
| Approximate rim width | 11.5" to 13.0" |
| In inches (flotation style) | 33.2x13.6R21 |
| 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 345/45R21 on a 21" wheel
These 21" sizes are within 3% of 345/45R21's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 285/55R21 | 33.34" | 11.22" | +0.4% | 60.2 mph | Compare |
| 315/50R21 | 33.40" | 12.40" | +0.5% | 60.3 mph | Compare |
| 305/50R21 | 33.01" | 12.01" | −0.7% | 59.6 mph | Compare |
| 275/55R21 | 32.91" | 10.83" | −0.9% | 59.4 mph | Compare |
| 335/45R21 | 32.87" | 13.19" | −1.1% | 59.4 mph | Compare |
| 355/45R21 | 33.58" | 13.98" | +1.1% | 60.6 mph | Compare |
| 295/55R21 | 33.78" | 11.61" | +1.7% | 61.0 mph | Compare |
| 325/50R21 | 33.80" | 12.80" | +1.7% | 61.0 mph | Compare |
| 295/50R21 | 32.61" | 11.61" | −1.8% | 58.9 mph | Compare |
| 325/45R21 | 32.52" | 12.80" | −2.1% | 58.7 mph | Compare |
| 265/55R21 | 32.48" | 10.43" | −2.3% | 58.6 mph | Compare |
| 335/50R21 | 34.19" | 13.19" | +2.9% | 61.7 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 285/50R22 | 22" | 33.22" | 0.0% | Compare |
| 335/35R24 | 24" | 33.23" | 0.0% | Compare |
| 305/55R20 | 20" | 33.21" | 0.0% | Compare |
| 275/75R17 | 17" | 33.24" | 0.0% | Compare |
| 295/70R17 | 17" | 33.26" | +0.1% | Compare |
| 335/50R20 | 20" | 33.19" | −0.1% | Compare |
| 355/40R22 | 22" | 33.18" | −0.1% | Compare |
| 315/45R22 | 22" | 33.16" | −0.2% | Compare |
| 275/70R18 | 18" | 33.16" | −0.2% | Compare |
| 295/40R24 | 24" | 33.29" | +0.2% | Compare |
| 275/80R16 | 16" | 33.32" | +0.3% | Compare |
| 315/65R17 | 17" | 33.12" | −0.3% | Compare |
One size up or down
- 335/45R21narrower: 32.9" × 13.2"
- 355/45R21wider: 33.6" × 14.0"
- 345/40R21lower profile: 31.9" × 13.6"
- 345/50R21taller sidewall: 34.6" × 13.6"
Compare 345/45R21 with another size
Questions
- How tall is a 345/45R21 tire?
- A 345/45R21 tire is 33.2 inches tall (844 mm), calculated from the size. It is 13.6 inches wide with 6.1 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 345/45R21 mean?
- 345/45R21 means a tire 345 mm wide, with sidewalls 45% as tall as the tire is wide (155 mm), radial construction (R), for a 21 inch wheel.
- How many revolutions per mile does a 345/45R21 tire make?
- About 607 revolutions per mile, based on a circumference of 104.4 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 345/45R21 tire?
- Roughly 11.5" to 13.0". Check the tire maker's approved rim range for the exact model before buying wheels.
- Can I use 285/55R21 instead of 345/45R21?
- 285/55R21 is +0.12 inches (+0.4%) in overall diameter, so at an indicated 60 mph you would be doing 60.2 mph. Differences under 3% are usually fine, but check clearance, load index and your vehicle's placard.