265/45R21 tire size
265/45R21 is a metric size: 30.4" tall, 10.4" wide, on a 21" rim — about a 30.5x10.50R21. The sidewall is 4.7" and the tire turns 664 times per mile.
265/45R21 specs
| Overall diameter (height) | 30.39" · 772 mm |
|---|---|
| Section width | 10.43" · 265 mm |
| Sidewall height | 4.69" · 119 mm (45% of width) |
| Rim diameter | 21" |
| Circumference | 95.47" · 2.425 m |
| Revolutions per mile | 664 (412 per km) |
| Inch (flotation) equivalent | 30.5x10.50R21 |
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 | |
|---|---|---|---|---|---|
| 265/40R21 common | 29.35" | -3.43% | 0 mm | 57.9 mph | compare → |
| 295/35R21 | 29.13" | -4.15% | +30 mm | 57.5 mph | compare → |
| 275/45R21 | 30.74" | +1.17% | +10 mm | 60.7 mph | compare → |
| 255/40R21 | 29.03" | -4.47% | -10 mm | 57.3 mph | compare → |
| 295/40R21 | 30.29" | -0.32% | +30 mm | 59.8 mph | compare → |
| 285/45R21 | 31.10" | +2.33% | +20 mm | 61.4 mph | compare → |
| 285/40R21 | 29.98" | -1.36% | +20 mm | 59.2 mph | compare → |
| 275/40R21 | 29.66" | -2.40% | +10 mm | 58.6 mph | compare → |
| 315/35R21 | 29.68" | -2.33% | +50 mm | 58.6 mph | compare → |
| 315/40R21 | 30.92" | +1.75% | +50 mm | 61.0 mph | compare → |
| 255/45R21 | 30.04" | -1.17% | -10 mm | 59.3 mph | compare → |
| 245/45R21 | 29.68" | -2.33% | -20 mm | 58.6 mph | compare → |
| 255/50R21 | 31.04" | +2.14% | -10 mm | 61.3 mph | compare → |
| 275/50R21 | 31.83" | +4.73% | +10 mm | 62.8 mph | compare → |
| 235/50R21 | 30.25" | -0.45% | -30 mm | 59.7 mph | calculate → |
| 235/45R21 | 29.33" | -3.50% | -30 mm | 57.9 mph | calculate → |
| 305/35R21 | 29.41" | -3.24% | +40 mm | 58.1 mph | calculate → |
| 335/30R21 | 28.91" | -4.86% | +70 mm | 57.1 mph | calculate → |
| 345/30R21 | 29.15" | -4.08% | +80 mm | 57.6 mph | calculate → |
| 225/45R21 | 28.97" | -4.66% | -40 mm | 57.2 mph | calculate → |
| 305/40R21 | 30.61" | +0.71% | +40 mm | 60.4 mph | calculate → |
| 325/40R21 | 31.24" | +2.79% | +60 mm | 61.7 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 | |
|---|---|---|---|---|---|
| 265/50R20 common | 30.43" | +0.14% | 0 mm | 60.1 mph | compare → |
| 235/55R20 common | 30.18" | -0.70% | -30 mm | 59.6 mph | compare → |
| 275/40R22 | 30.66" | +0.89% | +10 mm | 60.5 mph | compare → |
| 265/40R22 | 30.35" | -0.14% | 0 mm | 59.9 mph | compare → |
| 285/45R20 | 30.10" | -0.96% | +20 mm | 59.4 mph | compare → |
| 295/45R20 | 30.45" | +0.21% | +30 mm | 60.1 mph | compare → |
| 295/35R22 | 30.13" | -0.86% | +30 mm | 59.5 mph | compare → |
| 315/35R22 | 30.68" | +0.96% | +50 mm | 60.6 mph | compare → |
| 305/35R22 | 30.41" | +0.05% | +40 mm | 60.0 mph | calculate → |
Try another size against 265/45R21
Questions
What size is 265/45R21 in inches?
265/45R21 is about 30.4" tall and 10.4" wide on a 21-inch rim — roughly a 30.5x10.50R21 in inch sizing.
What does 265/45R21 mean?
265 mm section width, sidewall 45% of the width (4.69"), radial construction, 21-inch rim.
What tire sizes are equivalent to 265/45R21?
On the same 21" rim, within 3% of the diameter: 295/40R21 (-0.32%), 235/50R21 (-0.45%), 305/40R21 (+0.71%), 255/45R21 (-1.17%), 275/45R21 (+1.17%), 285/40R21 (-1.36%).
How many revolutions per mile does a 265/45R21 tire make?
About 664 revolutions per mile (circumference 95.5").
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.