225/55R21 tire size in inches
A 225/55R21 tire measures
30.7" tall × 8.9" wide
4.87" sidewall on a 21" wheel. 656 revolutions per mile.
225/55R21 means a tire 225 mm wide, with sidewalls 55% as tall as the tire is wide (124 mm), radial construction (R), for a 21 inch wheel.
225/55R21 specs
| Overall diameter (height) | 30.74 inches (781 mm) |
|---|---|
| Section width | 8.86 inches (225 mm) |
| Sidewall height | 4.87 inches (124 mm) |
| Wheel (rim) diameter | 21 inches |
| Circumference | 96.6 inches (2,453 mm) |
| Revolutions per mile | 656 |
| Revolutions per kilometer | 408 |
| Approximate rim width | 6.5" to 8.0" |
| In inches (flotation style) | 30.7x8.9R21 |
| Aspect ratio | 55% |
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 225/55R21 on a 21" wheel
These 21" sizes are within 3% of 225/55R21's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 275/45R21 | 30.74" | 10.83" | 0.0% | 60.0 mph | Compare |
| 355/35R21 | 30.78" | 13.98" | +0.1% | 60.1 mph | Compare |
| 245/50R21 | 30.65" | 9.65" | −0.3% | 59.8 mph | Compare |
| 305/40R21 | 30.61" | 12.01" | −0.4% | 59.7 mph | Compare |
| 315/40R21 | 30.92" | 12.40" | +0.6% | 60.3 mph | Compare |
| 345/35R21 | 30.51" | 13.58" | −0.8% | 59.5 mph | Compare |
| 255/50R21 | 31.04" | 10.04" | +1.0% | 60.6 mph | Compare |
| 285/45R21 | 31.10" | 11.22" | +1.2% | 60.7 mph | Compare |
| 265/45R21 | 30.39" | 10.43" | −1.2% | 59.3 mph | Compare |
| 235/55R21 | 31.18" | 9.25" | +1.4% | 60.8 mph | Compare |
| 295/40R21 | 30.29" | 11.61" | −1.5% | 59.1 mph | Compare |
| 235/50R21 | 30.25" | 9.25" | −1.6% | 59.0 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 285/30R24 | 24" | 30.73" | 0.0% | Compare |
| 235/85R15 | 15" | 30.73" | −0.1% | Compare |
| 295/55R18 | 18" | 30.78" | +0.1% | Compare |
| 285/70R15 | 15" | 30.71" | −0.1% | Compare |
| 215/75R18 | 18" | 30.70" | −0.2% | Compare |
| 345/25R24 | 24" | 30.79" | +0.2% | Compare |
| 265/80R14 | 14" | 30.69" | −0.2% | Compare |
| 325/50R18 | 18" | 30.80" | +0.2% | Compare |
| 235/80R16 | 16" | 30.80" | +0.2% | Compare |
| 245/45R22 | 22" | 30.68" | −0.2% | Compare |
| 305/45R20 | 20" | 30.81" | +0.2% | Compare |
| 315/35R22 | 22" | 30.68" | −0.2% | Compare |
One size up or down
Compare 225/55R21 with another size
Questions
- How tall is a 225/55R21 tire?
- A 225/55R21 tire is 30.7 inches tall (781 mm), calculated from the size. It is 8.9 inches wide with 4.9 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 225/55R21 mean?
- 225/55R21 means a tire 225 mm wide, with sidewalls 55% as tall as the tire is wide (124 mm), radial construction (R), for a 21 inch wheel.
- How many revolutions per mile does a 225/55R21 tire make?
- About 656 revolutions per mile, based on a circumference of 96.6 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 225/55R21 tire?
- Roughly 6.5" to 8.0". Check the tire maker's approved rim range for the exact model before buying wheels.
- Can I use 275/45R21 instead of 225/55R21?
- 275/45R21 is 0.00 inches (0.0%) 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.