355/30R21 tire size in inches
A 355/30R21 tire measures
29.4" tall × 14.0" wide
4.19" sidewall on a 21" wheel. 686 revolutions per mile.
355/30R21 means a tire 355 mm wide, with sidewalls 30% as tall as the tire is wide (107 mm), radial construction (R), for a 21 inch wheel.
355/30R21 specs
| Overall diameter (height) | 29.39 inches (746 mm) |
|---|---|
| Section width | 13.98 inches (355 mm) |
| Sidewall height | 4.19 inches (107 mm) |
| Wheel (rim) diameter | 21 inches |
| Circumference | 92.3 inches (2,345 mm) |
| Revolutions per mile | 686 |
| Revolutions per kilometer | 426 |
| Approximate rim width | 11.5" to 13.0" |
| In inches (flotation style) | 29.4x14.0R21 |
| 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 355/30R21 on a 21" wheel
These 21" sizes are within 3% of 355/30R21's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 305/35R21 | 29.41" | 12.01" | +0.1% | 60.0 mph | Compare |
| 265/40R21 | 29.35" | 10.43" | −0.1% | 59.9 mph | Compare |
| 235/45R21 | 29.33" | 9.25" | −0.2% | 59.9 mph | Compare |
| 345/30R21 | 29.15" | 13.58" | −0.8% | 59.5 mph | Compare |
| 295/35R21 | 29.13" | 11.61" | −0.9% | 59.5 mph | Compare |
| 275/40R21 | 29.66" | 10.83" | +0.9% | 60.6 mph | Compare |
| 245/45R21 | 29.68" | 9.65" | +1.0% | 60.6 mph | Compare |
| 315/35R21 | 29.68" | 12.40" | +1.0% | 60.6 mph | Compare |
| 255/40R21 | 29.03" | 10.04" | −1.2% | 59.3 mph | Compare |
| 225/45R21 | 28.97" | 8.86" | −1.4% | 59.2 mph | Compare |
| 225/50R21 | 29.86" | 8.86" | +1.6% | 61.0 mph | Compare |
| 335/30R21 | 28.91" | 13.19" | −1.6% | 59.0 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 215/85R15 | 15" | 29.39" | 0.0% | Compare |
| 265/45R20 | 20" | 29.39" | 0.0% | Compare |
| 245/85R13 | 13" | 29.40" | 0.0% | Compare |
| 225/70R17 | 17" | 29.40" | +0.1% | Compare |
| 235/40R22 | 22" | 29.40" | +0.1% | Compare |
| 315/50R17 | 17" | 29.40" | +0.1% | Compare |
| 275/25R24 | 24" | 29.41" | +0.1% | Compare |
| 285/55R17 | 17" | 29.34" | −0.1% | Compare |
| 245/80R14 | 14" | 29.43" | +0.2% | Compare |
| 265/50R19 | 19" | 29.43" | +0.2% | Compare |
| 315/30R22 | 22" | 29.44" | +0.2% | Compare |
| 295/45R19 | 19" | 29.45" | +0.2% | Compare |
One size up or down
- 345/30R21narrower: 29.1" × 13.6"
- 355/25R21lower profile: 28.0" × 14.0"
- 355/35R21taller sidewall: 30.8" × 14.0"
Compare 355/30R21 with another size
Questions
- How tall is a 355/30R21 tire?
- A 355/30R21 tire is 29.4 inches tall (746 mm), calculated from the size. It is 14.0 inches wide with 4.2 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 355/30R21 mean?
- 355/30R21 means a tire 355 mm wide, with sidewalls 30% as tall as the tire is wide (107 mm), radial construction (R), for a 21 inch wheel.
- How many revolutions per mile does a 355/30R21 tire make?
- About 686 revolutions per mile, based on a circumference of 92.3 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 355/30R21 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 305/35R21 instead of 355/30R21?
- 305/35R21 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.