345/30R21 tire size in inches
A 345/30R21 tire measures
29.1" tall × 13.6" wide
4.07" sidewall on a 21" wheel. 692 revolutions per mile.
345/30R21 means a tire 345 mm wide, with sidewalls 30% as tall as the tire is wide (103 mm), radial construction (R), for a 21 inch wheel.
345/30R21 specs
| Overall diameter (height) | 29.15 inches (740 mm) |
|---|---|
| Section width | 13.58 inches (345 mm) |
| Sidewall height | 4.07 inches (103 mm) |
| Wheel (rim) diameter | 21 inches |
| Circumference | 91.6 inches (2,326 mm) |
| Revolutions per mile | 692 |
| Revolutions per kilometer | 430 |
| Approximate rim width | 11.5" to 13.0" |
| In inches (flotation style) | 29.1x13.6R21 |
| Aspect ratio | 30% |
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 345/30R21 on a 21" wheel
These 21" sizes are within 3% of 345/30R21's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 295/35R21 | 29.13" | 11.61" | −0.1% | 60.0 mph | Compare |
| 255/40R21 | 29.03" | 10.04" | −0.4% | 59.8 mph | Compare |
| 235/45R21 | 29.33" | 9.25" | +0.6% | 60.4 mph | Compare |
| 225/45R21 | 28.97" | 8.86" | −0.6% | 59.6 mph | Compare |
| 265/40R21 | 29.35" | 10.43" | +0.7% | 60.4 mph | Compare |
| 355/30R21 | 29.39" | 13.98" | +0.8% | 60.5 mph | Compare |
| 335/30R21 | 28.91" | 13.19" | −0.8% | 59.5 mph | Compare |
| 305/35R21 | 29.41" | 12.01" | +0.9% | 60.5 mph | Compare |
| 285/35R21 | 28.85" | 11.22" | −1.0% | 59.4 mph | Compare |
| 245/40R21 | 28.72" | 9.65" | −1.5% | 59.1 mph | Compare |
| 325/30R21 | 28.68" | 12.80" | −1.6% | 59.0 mph | Compare |
| 275/40R21 | 29.66" | 10.83" | +1.8% | 61.1 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 215/60R19 | 19" | 29.16" | 0.0% | Compare |
| 315/45R18 | 18" | 29.16" | 0.0% | Compare |
| 225/80R15 | 15" | 29.17" | +0.1% | Compare |
| 235/55R19 | 19" | 29.18" | +0.1% | Compare |
| 205/75R17 | 17" | 29.11" | −0.1% | Compare |
| 235/60R18 | 18" | 29.10" | −0.2% | Compare |
| 285/45R19 | 19" | 29.10" | −0.2% | Compare |
| 305/30R22 | 22" | 29.20" | +0.2% | Compare |
| 265/25R24 | 24" | 29.22" | +0.2% | Compare |
| 285/50R18 | 18" | 29.22" | +0.2% | Compare |
| 275/65R15 | 15" | 29.07" | −0.3% | Compare |
| 335/35R20 | 20" | 29.23" | +0.3% | Compare |
One size up or down
- 335/30R21narrower: 28.9" × 13.2"
- 355/30R21wider: 29.4" × 14.0"
- 345/25R21lower profile: 27.8" × 13.6"
- 345/35R21taller sidewall: 30.5" × 13.6"
Compare 345/30R21 with another size
Questions
- How tall is a 345/30R21 tire?
- A 345/30R21 tire is 29.1 inches tall (740 mm), calculated from the size. It is 13.6 inches wide with 4.1 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 345/30R21 mean?
- 345/30R21 means a tire 345 mm wide, with sidewalls 30% as tall as the tire is wide (103 mm), radial construction (R), for a 21 inch wheel.
- How many revolutions per mile does a 345/30R21 tire make?
- About 692 revolutions per mile, based on a circumference of 91.6 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 345/30R21 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 295/35R21 instead of 345/30R21?
- 295/35R21 is −0.02 inches (−0.1%) in overall diameter, so at an indicated 60 mph you would be doing 60.0 mph. Differences under 3% are usually fine, but check clearance, load index and your vehicle's placard.