275/55R21 tire size
275/55R21 is a metric size: 32.9" tall, 10.8" wide, on a 21" rim — about a 33x11.00R21. The sidewall is 6.0" and the tire turns 613 times per mile.
275/55R21 specs
| Overall diameter (height) | 32.91" · 836 mm |
|---|---|
| Section width | 10.83" · 275 mm |
| Sidewall height | 5.95" · 151 mm (55% of width) |
| Rim diameter | 21" |
| Circumference | 103.39" · 2.626 m |
| Revolutions per mile | 613 (381 per km) |
| Inch (flotation) equivalent | 33x11.00R21 |
Equivalent sizes on a 21" rim
Sizes within ±5% of the overall diameter. Green rows are inside the usual ±3% limit for keeping the speedometer, ABS and gearing right; red rows are bigger changes that need clearance checks.
| Size | Diameter | Difference | Width | Speedo at 60 | |
|---|---|---|---|---|---|
| 275/50R21 | 31.83" | -3.29% | 0 mm | 58.0 mph | calculate → |
| 315/45R21 | 32.16" | -2.27% | +40 mm | 58.6 mph | calculate → |
Plus / minus sizing: 20" and 22" rims
Same overall height on a different rim. Check wheel width and clearance before switching.
| Size | Diameter | Difference | Width | Speedo at 60 | |
|---|---|---|---|---|---|
| 275/60R20 common | 32.99" | +0.25% | 0 mm | 60.2 mph | calculate → |
| 305/55R20 common | 33.21" | +0.91% | +30 mm | 60.5 mph | calculate → |
| 33x12.50R20 common | 33.00" | +0.28% | +43 mm | 60.2 mph | calculate → |
| 275/50R22 common | 32.83" | -0.25% | 0 mm | 59.8 mph | calculate → |
| 295/55R20 | 32.78" | -0.41% | +20 mm | 59.8 mph | calculate → |
| 305/45R22 | 32.81" | -0.31% | +30 mm | 59.8 mph | calculate → |
| 33x12.50R22 | 33.00" | +0.28% | +43 mm | 60.2 mph | calculate → |
| 285/50R22 | 33.22" | +0.95% | +10 mm | 60.6 mph | calculate → |
| 33x13.50R20 | 33.00" | +0.28% | +68 mm | 60.2 mph | calculate → |
| 33x11.50R20 | 33.00" | +0.28% | +17 mm | 60.2 mph | calculate → |
| 315/45R22 | 33.16" | +0.77% | +40 mm | 60.5 mph | calculate → |
| 355/40R22 | 33.18" | +0.83% | +80 mm | 60.5 mph | calculate → |
| 33x12.00R20 | 33.00" | +0.28% | +30 mm | 60.2 mph | calculate → |
| 33x13.50R22 | 33.00" | +0.28% | +68 mm | 60.2 mph | calculate → |
| 33x14.50R22 | 33.00" | +0.28% | +93 mm | 60.2 mph | calculate → |
| 33x22.00R20 | 33.00" | +0.28% | +284 mm | 60.2 mph | calculate → |
| 325/50R20 | 32.80" | -0.35% | +50 mm | 59.8 mph | calculate → |
| 33x14.50R20 | 33.00" | +0.28% | +93 mm | 60.2 mph | calculate → |
Try another size against 275/55R21
Questions
What size is 275/55R21 in inches?
275/55R21 is about 32.9" tall and 10.8" wide on a 21-inch rim — roughly a 33x11.00R21 in inch sizing.
What does 275/55R21 mean?
275 mm section width, sidewall 55% of the width (5.95"), radial construction, 21-inch rim.
What tire sizes are equivalent to 275/55R21?
On the same 21" rim, within 3% of the diameter: 315/45R21 (-2.27%), 275/50R21 (-3.29%).
How many revolutions per mile does a 275/55R21 tire make?
About 613 revolutions per mile (circumference 103.4").
How these numbers are computed
Diameter = rim + 2 × sidewall, sidewall = width × aspect ÷ 100, circumference = π × diameter, revolutions per mile = 63,360 ÷ circumference. Real tires differ by brand by a few tenths of an inch. Last reviewed October 14, 2026.