265/30R21 tire size
265/30R21 is a metric size: 27.3" tall, 10.4" wide, on a 21" rim — about a 27.5x10.50R21. The sidewall is 3.1" and the tire turns 740 times per mile.
265/30R21 specs
| Overall diameter (height) | 27.26" · 692 mm |
|---|---|
| Section width | 10.43" · 265 mm |
| Sidewall height | 3.13" · 80 mm (30% of width) |
| Rim diameter | 21" |
| Circumference | 85.64" · 2.175 m |
| Revolutions per mile | 740 (460 per km) |
| Inch (flotation) equivalent | 27.5x10.50R21 |
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 | |
|---|---|---|---|---|---|
| 275/35R21 common | 28.58" | +4.84% | +10 mm | 62.9 mph | calculate → |
| 265/35R21 | 28.30" | +3.83% | 0 mm | 62.3 mph | calculate → |
| 245/35R21 | 27.75" | +1.81% | -20 mm | 61.1 mph | calculate → |
| 255/35R21 | 28.03" | +2.82% | -10 mm | 61.7 mph | calculate → |
| 315/30R21 | 28.44" | +4.33% | +50 mm | 62.6 mph | calculate → |
| 295/30R21 | 27.97" | +2.60% | +30 mm | 61.6 mph | calculate → |
| 305/30R21 | 28.20" | +3.47% | +40 mm | 62.1 mph | calculate → |
| 285/30R21 | 27.73" | +1.73% | +20 mm | 61.0 mph | calculate → |
| 275/30R21 | 27.50" | +0.87% | +10 mm | 60.5 mph | calculate → |
| 255/30R21 | 27.02" | -0.87% | -10 mm | 59.5 mph | calculate → |
| 355/25R21 | 27.99" | +2.67% | +90 mm | 61.6 mph | calculate → |
| 295/25R21 | 26.81" | -1.66% | +30 mm | 59.0 mph | calculate → |
| 325/25R21 | 27.40" | +0.51% | +60 mm | 60.3 mph | calculate → |
| 305/25R21 | 27.00" | -0.94% | +40 mm | 59.4 mph | calculate → |
| 345/25R21 | 27.79" | +1.95% | +80 mm | 61.2 mph | calculate → |
| 245/30R21 | 26.79" | -1.73% | -20 mm | 59.0 mph | calculate → |
| 275/25R21 | 26.41" | -3.11% | +10 mm | 58.1 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 | |
|---|---|---|---|---|---|
| 255/35R20 common | 27.03" | -0.85% | -10 mm | 59.5 mph | calculate → |
| 265/35R20 common | 27.30" | +0.16% | 0 mm | 60.1 mph | calculate → |
| 305/30R20 | 27.20" | -0.20% | +40 mm | 59.9 mph | calculate → |
| 315/30R20 | 27.44" | +0.66% | +50 mm | 60.4 mph | calculate → |
| 235/40R20 | 27.40" | +0.52% | -30 mm | 60.3 mph | calculate → |
| 225/40R20 | 27.09" | -0.64% | -40 mm | 59.6 mph | calculate → |
| 155/60R20 | 27.32" | +0.23% | -110 mm | 60.1 mph | calculate → |
| 275/25R22 | 27.41" | +0.56% | +10 mm | 60.3 mph | calculate → |
| 145/65R20 | 27.42" | +0.59% | -120 mm | 60.4 mph | calculate → |
Try another size against 265/30R21
Questions
What size is 265/30R21 in inches?
265/30R21 is about 27.3" tall and 10.4" wide on a 21-inch rim — roughly a 27.5x10.50R21 in inch sizing.
What does 265/30R21 mean?
265 mm section width, sidewall 30% of the width (3.13"), radial construction, 21-inch rim.
What tire sizes are equivalent to 265/30R21?
On the same 21" rim, within 3% of the diameter: 325/25R21 (+0.51%), 255/30R21 (-0.87%), 275/30R21 (+0.87%), 305/25R21 (-0.94%), 295/25R21 (-1.66%), 285/30R21 (+1.73%).
How many revolutions per mile does a 265/30R21 tire make?
About 740 revolutions per mile (circumference 85.6").
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.