235/45R21 tire size in inches
A 235/45R21 tire measures
29.3" tall × 9.3" wide
4.16" sidewall on a 21" wheel. 688 revolutions per mile.
235/45R21 means a tire 235 mm wide, with sidewalls 45% as tall as the tire is wide (106 mm), radial construction (R), for a 21 inch wheel.
235/45R21 specs
| Overall diameter (height) | 29.33 inches (745 mm) |
|---|---|
| Section width | 9.25 inches (235 mm) |
| Sidewall height | 4.16 inches (106 mm) |
| Wheel (rim) diameter | 21 inches |
| Circumference | 92.1 inches (2,340 mm) |
| Revolutions per mile | 688 |
| Revolutions per kilometer | 427 |
| Approximate rim width | 7.5" to 9.0" |
| In inches (flotation style) | 29.3x9.3R21 |
| 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 235/45R21 on a 21" wheel
These 21" sizes are within 3% of 235/45R21's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 265/40R21 | 29.35" | 10.43" | +0.1% | 60.0 mph | Compare |
| 355/30R21 | 29.39" | 13.98" | +0.2% | 60.1 mph | Compare |
| 305/35R21 | 29.41" | 12.01" | +0.3% | 60.2 mph | Compare |
| 345/30R21 | 29.15" | 13.58" | −0.6% | 59.6 mph | Compare |
| 295/35R21 | 29.13" | 11.61" | −0.7% | 59.6 mph | Compare |
| 255/40R21 | 29.03" | 10.04" | −1.0% | 59.4 mph | Compare |
| 275/40R21 | 29.66" | 10.83" | +1.1% | 60.7 mph | Compare |
| 225/45R21 | 28.97" | 8.86" | −1.2% | 59.3 mph | Compare |
| 245/45R21 | 29.68" | 9.65" | +1.2% | 60.7 mph | Compare |
| 315/35R21 | 29.68" | 12.40" | +1.2% | 60.7 mph | Compare |
| 335/30R21 | 28.91" | 13.19" | −1.4% | 59.2 mph | Compare |
| 285/35R21 | 28.85" | 11.22" | −1.6% | 59.0 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 215/55R20 | 20" | 29.31" | −0.1% | Compare |
| 285/55R17 | 17" | 29.34" | +0.1% | Compare |
| 265/35R22 | 22" | 29.30" | −0.1% | Compare |
| 205/70R18 | 18" | 29.30" | −0.1% | Compare |
| 295/40R20 | 20" | 29.29" | −0.1% | Compare |
| 225/75R16 | 16" | 29.29" | −0.1% | Compare |
| 215/85R15 | 15" | 29.39" | +0.2% | Compare |
| 265/45R20 | 20" | 29.39" | +0.2% | Compare |
| 245/85R13 | 13" | 29.40" | +0.2% | Compare |
| 225/70R17 | 17" | 29.40" | +0.3% | Compare |
| 235/50R20 | 20" | 29.25" | −0.3% | Compare |
| 235/40R22 | 22" | 29.40" | +0.3% | Compare |
One size up or down
- 225/45R21narrower: 29.0" × 8.9"
- 245/45R21wider: 29.7" × 9.6"
- 235/40R21lower profile: 28.4" × 9.3"
- 235/50R21taller sidewall: 30.3" × 9.3"
Compare 235/45R21 with another size
Questions
- How tall is a 235/45R21 tire?
- A 235/45R21 tire is 29.3 inches tall (745 mm), calculated from the size. It is 9.3 inches wide with 4.2 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 235/45R21 mean?
- 235/45R21 means a tire 235 mm wide, with sidewalls 45% as tall as the tire is wide (106 mm), radial construction (R), for a 21 inch wheel.
- How many revolutions per mile does a 235/45R21 tire make?
- About 688 revolutions per mile, based on a circumference of 92.1 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 235/45R21 tire?
- Roughly 7.5" to 9.0". Check the tire maker's approved rim range for the exact model before buying wheels.
- Can I use 265/40R21 instead of 235/45R21?
- 265/40R21 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.