275/35R21 tire size
275/35R21 is a metric size: 28.6" tall, 10.8" wide, on a 21" rim — about a 28.5x11.00R21. The sidewall is 3.8" and the tire turns 706 times per mile.
275/35R21 specs
| Overall diameter (height) | 28.58" · 726 mm |
|---|---|
| Section width | 10.83" · 275 mm |
| Sidewall height | 3.79" · 96 mm (35% of width) |
| Rim diameter | 21" |
| Circumference | 89.78" · 2.280 m |
| Revolutions per mile | 706 (439 per km) |
| Inch (flotation) equivalent | 28.5x11.00R21 |
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 | |
|---|---|---|---|---|---|
| 265/40R21 common | 29.35" | +2.69% | -10 mm | 61.6 mph | compare → |
| 295/35R21 | 29.13" | +1.93% | +20 mm | 61.2 mph | compare → |
| 255/40R21 | 29.03" | +1.58% | -20 mm | 61.0 mph | compare → |
| 265/35R21 | 28.30" | -0.96% | -10 mm | 59.4 mph | compare → |
| 245/35R21 | 27.75" | -2.89% | -30 mm | 58.3 mph | compare → |
| 285/40R21 | 29.98" | +4.89% | +10 mm | 62.9 mph | compare → |
| 325/30R21 | 28.68" | +0.34% | +50 mm | 60.2 mph | compare → |
| 275/40R21 | 29.66" | +3.79% | 0 mm | 62.3 mph | compare → |
| 255/35R21 | 28.03" | -1.93% | -20 mm | 58.8 mph | compare → |
| 315/30R21 | 28.44" | -0.48% | +40 mm | 59.7 mph | compare → |
| 285/35R21 | 28.85" | +0.96% | +10 mm | 60.6 mph | compare → |
| 245/40R21 | 28.72" | +0.48% | -30 mm | 60.3 mph | compare → |
| 315/35R21 | 29.68" | +3.86% | +40 mm | 62.3 mph | compare → |
| 305/30R21 | 28.20" | -1.31% | +30 mm | 59.2 mph | compare → |
| 295/30R21 | 27.97" | -2.14% | +20 mm | 58.7 mph | compare → |
| 285/30R21 | 27.73" | -2.96% | +10 mm | 58.2 mph | compare → |
| 275/30R21 | 27.50" | -3.79% | 0 mm | 57.7 mph | compare → |
| 245/45R21 | 29.68" | +3.86% | -30 mm | 62.3 mph | compare → |
| 355/25R21 | 27.99" | -2.07% | +80 mm | 58.8 mph | calculate → |
| 235/45R21 | 29.33" | +2.62% | -40 mm | 61.6 mph | calculate → |
| 335/30R21 | 28.91" | +1.17% | +60 mm | 60.7 mph | calculate → |
| 305/35R21 | 29.41" | +2.89% | +30 mm | 61.7 mph | calculate → |
| 345/30R21 | 29.15" | +2.00% | +70 mm | 61.2 mph | calculate → |
| 265/30R21 | 27.26" | -4.61% | -10 mm | 57.2 mph | calculate → |
| 225/45R21 | 28.97" | +1.38% | -50 mm | 60.8 mph | calculate → |
| 345/25R21 | 27.79" | -2.76% | +70 mm | 58.3 mph | calculate → |
| 325/25R21 | 27.40" | -4.13% | +50 mm | 57.5 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 | |
|---|---|---|---|---|---|
| 245/45R20 common | 28.68" | +0.36% | -30 mm | 60.2 mph | compare → |
| 275/40R20 common | 28.66" | +0.29% | 0 mm | 60.2 mph | compare → |
| 315/35R20 common | 28.68" | +0.36% | +40 mm | 60.2 mph | compare → |
| 305/35R20 | 28.41" | -0.61% | +30 mm | 59.6 mph | compare → |
| 235/45R20 | 28.33" | -0.88% | -40 mm | 59.5 mph | compare → |
| 265/40R20 | 28.35" | -0.81% | -10 mm | 59.5 mph | compare → |
| 285/30R22 | 28.73" | +0.54% | +10 mm | 60.3 mph | compare → |
| 335/25R22 | 28.59" | +0.06% | +60 mm | 60.0 mph | calculate → |
| 275/30R22 | 28.50" | -0.29% | 0 mm | 59.8 mph | calculate → |
| 195/55R20 | 28.44" | -0.47% | -80 mm | 59.7 mph | calculate → |
Try another size against 275/35R21
Questions
What size is 275/35R21 in inches?
275/35R21 is about 28.6" tall and 10.8" wide on a 21-inch rim — roughly a 28.5x11.00R21 in inch sizing.
What does 275/35R21 mean?
275 mm section width, sidewall 35% of the width (3.79"), radial construction, 21-inch rim.
What tire sizes are equivalent to 275/35R21?
On the same 21" rim, within 3% of the diameter: 325/30R21 (+0.34%), 245/40R21 (+0.48%), 315/30R21 (-0.48%), 265/35R21 (-0.96%), 285/35R21 (+0.96%), 335/30R21 (+1.17%).
How many revolutions per mile does a 275/35R21 tire make?
About 706 revolutions per mile (circumference 89.8").
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.