315/50R21 tire size in inches
A 315/50R21 tire measures
33.4" tall × 12.4" wide
6.20" sidewall on a 21" wheel. 604 revolutions per mile.
315/50R21 means a tire 315 mm wide, with sidewalls 50% as tall as the tire is wide (158 mm), radial construction (R), for a 21 inch wheel.
315/50R21 specs
| Overall diameter (height) | 33.40 inches (848 mm) |
|---|---|
| Section width | 12.40 inches (315 mm) |
| Sidewall height | 6.20 inches (158 mm) |
| Wheel (rim) diameter | 21 inches |
| Circumference | 104.9 inches (2,665 mm) |
| Revolutions per mile | 604 |
| Revolutions per kilometer | 375 |
| Approximate rim width | 9.0" to 10.5" |
| In inches (flotation style) | 33.4x12.4R21 |
| Aspect ratio | 50% |
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 315/50R21 on a 21" wheel
These 21" sizes are within 3% of 315/50R21's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 285/55R21 | 33.34" | 11.22" | −0.2% | 59.9 mph | Compare |
| 355/45R21 | 33.58" | 13.98" | +0.5% | 60.3 mph | Compare |
| 345/45R21 | 33.22" | 13.58" | −0.5% | 59.7 mph | Compare |
| 295/55R21 | 33.78" | 11.61" | +1.1% | 60.7 mph | Compare |
| 305/50R21 | 33.01" | 12.01" | −1.2% | 59.3 mph | Compare |
| 325/50R21 | 33.80" | 12.80" | +1.2% | 60.7 mph | Compare |
| 275/55R21 | 32.91" | 10.83" | −1.5% | 59.1 mph | Compare |
| 335/45R21 | 32.87" | 13.19" | −1.6% | 59.0 mph | Compare |
| 295/50R21 | 32.61" | 11.61" | −2.4% | 58.6 mph | Compare |
| 335/50R21 | 34.19" | 13.19" | +2.4% | 61.4 mph | Compare |
| 305/55R21 | 34.21" | 12.01" | +2.4% | 61.4 mph | Compare |
| 325/45R21 | 32.52" | 12.80" | −2.7% | 58.4 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 275/85R15 | 15" | 33.41" | 0.0% | Compare |
| 305/60R19 | 19" | 33.41" | 0.0% | Compare |
| 295/75R16 | 16" | 33.42" | +0.1% | Compare |
| 325/60R18 | 18" | 33.35" | −0.1% | Compare |
| 285/60R20 | 20" | 33.46" | +0.2% | Compare |
| 265/55R22 | 22" | 33.48" | +0.2% | Compare |
| 275/80R16 | 16" | 33.32" | −0.2% | Compare |
| 335/55R19 | 19" | 33.51" | +0.3% | Compare |
| 345/35R24 | 24" | 33.51" | +0.3% | Compare |
| 295/40R24 | 24" | 33.29" | −0.3% | Compare |
| 325/45R22 | 22" | 33.52" | +0.3% | Compare |
| 295/70R17 | 17" | 33.26" | −0.4% | Compare |
One size up or down
- 305/50R21narrower: 33.0" × 12.0"
- 325/50R21wider: 33.8" × 12.8"
- 315/45R21lower profile: 32.2" × 12.4"
- 315/55R21taller sidewall: 34.6" × 12.4"
Compare 315/50R21 with another size
Questions
- How tall is a 315/50R21 tire?
- A 315/50R21 tire is 33.4 inches tall (848 mm), calculated from the size. It is 12.4 inches wide with 6.2 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 315/50R21 mean?
- 315/50R21 means a tire 315 mm wide, with sidewalls 50% as tall as the tire is wide (158 mm), radial construction (R), for a 21 inch wheel.
- How many revolutions per mile does a 315/50R21 tire make?
- About 604 revolutions per mile, based on a circumference of 104.9 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 315/50R21 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 285/55R21 instead of 315/50R21?
- 285/55R21 is −0.06 inches (−0.2%) in overall diameter, so at an indicated 60 mph you would be doing 59.9 mph. Differences under 3% are usually fine, but check clearance, load index and your vehicle's placard.