275/30R21 tire size in inches
A 275/30R21 tire measures
27.5" tall × 10.8" wide
3.25" sidewall on a 21" wheel. 733 revolutions per mile.
275/30R21 means a tire 275 mm wide, with sidewalls 30% as tall as the tire is wide (83 mm), radial construction (R), for a 21 inch wheel.
275/30R21 specs
| Overall diameter (height) | 27.50 inches (698 mm) |
|---|---|
| Section width | 10.83 inches (275 mm) |
| Sidewall height | 3.25 inches (83 mm) |
| Wheel (rim) diameter | 21 inches |
| Circumference | 86.4 inches (2,194 mm) |
| Revolutions per mile | 733 |
| Revolutions per kilometer | 456 |
| Approximate rim width | 9.0" to 10.5" |
| In inches (flotation style) | 27.5x10.8R21 |
| 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 275/30R21 on a 21" wheel
These 21" sizes are within 3% of 275/30R21's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 235/35R21 | 27.48" | 9.25" | −0.1% | 60.0 mph | Compare |
| 325/25R21 | 27.40" | 12.80" | −0.4% | 59.8 mph | Compare |
| 335/25R21 | 27.59" | 13.19" | +0.4% | 60.2 mph | Compare |
| 265/30R21 | 27.26" | 10.43" | −0.9% | 59.5 mph | Compare |
| 285/30R21 | 27.73" | 11.22" | +0.9% | 60.5 mph | Compare |
| 245/35R21 | 27.75" | 9.65" | +0.9% | 60.6 mph | Compare |
| 225/35R21 | 27.20" | 8.86" | −1.1% | 59.4 mph | Compare |
| 315/25R21 | 27.20" | 12.40" | −1.1% | 59.4 mph | Compare |
| 345/25R21 | 27.79" | 13.58" | +1.1% | 60.6 mph | Compare |
| 255/30R21 | 27.02" | 10.04" | −1.7% | 59.0 mph | Compare |
| 295/30R21 | 27.97" | 11.61" | +1.7% | 61.0 mph | Compare |
| 355/25R21 | 27.99" | 13.98" | +1.8% | 61.1 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 205/65R17 | 17" | 27.49" | 0.0% | Compare |
| 245/70R14 | 14" | 27.50" | 0.0% | Compare |
| 195/75R16 | 16" | 27.52" | +0.1% | Compare |
| 225/65R16 | 16" | 27.52" | +0.1% | Compare |
| 265/55R16 | 16" | 27.48" | −0.1% | Compare |
| 265/60R15 | 15" | 27.52" | +0.1% | Compare |
| 245/75R13 | 13" | 27.47" | −0.1% | Compare |
| 215/50R19 | 19" | 27.46" | −0.1% | Compare |
| 245/65R15 | 15" | 27.54" | +0.2% | Compare |
| 295/45R17 | 17" | 27.45" | −0.2% | Compare |
| 215/80R14 | 14" | 27.54" | +0.2% | Compare |
| 235/30R22 | 22" | 27.55" | +0.2% | Compare |
One size up or down
- 265/30R21narrower: 27.3" × 10.4"
- 285/30R21wider: 27.7" × 11.2"
- 275/25R21lower profile: 26.4" × 10.8"
- 275/35R21taller sidewall: 28.6" × 10.8"
Compare 275/30R21 with another size
Questions
- How tall is a 275/30R21 tire?
- A 275/30R21 tire is 27.5 inches tall (698 mm), calculated from the size. It is 10.8 inches wide with 3.2 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 275/30R21 mean?
- 275/30R21 means a tire 275 mm wide, with sidewalls 30% as tall as the tire is wide (83 mm), radial construction (R), for a 21 inch wheel.
- How many revolutions per mile does a 275/30R21 tire make?
- About 733 revolutions per mile, based on a circumference of 86.4 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 275/30R21 tire?
- Roughly 9.0" to 10.5". Check the tire maker's approved rim range for the exact model before buying wheels.
- Can I use 235/35R21 instead of 275/30R21?
- 235/35R21 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.