285/35R21 tire size
285/35R21 is a metric size: 28.9" tall, 11.2" wide, on a 21" rim — about a 29x11.00R21. The sidewall is 3.9" and the tire turns 699 times per mile.
285/35R21 specs
| Overall diameter (height) | 28.85" · 733 mm |
|---|---|
| Section width | 11.22" · 285 mm |
| Sidewall height | 3.93" · 100 mm (35% of width) |
| Rim diameter | 21" |
| Circumference | 90.65" · 2.302 m |
| Revolutions per mile | 699 (434 per km) |
| Inch (flotation) equivalent | 29x11.00R21 |
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" | +1.71% | -20 mm | 61.0 mph | compare → |
| 275/35R21 common | 28.58" | -0.96% | -10 mm | 59.4 mph | compare → |
| 295/35R21 | 29.13" | +0.96% | +10 mm | 60.6 mph | compare → |
| 255/40R21 | 29.03" | +0.61% | -30 mm | 60.4 mph | compare → |
| 265/35R21 | 28.30" | -1.91% | -20 mm | 58.9 mph | compare → |
| 245/35R21 | 27.75" | -3.82% | -40 mm | 57.7 mph | compare → |
| 295/40R21 | 30.29" | +4.98% | +10 mm | 63.0 mph | compare → |
| 285/40R21 | 29.98" | +3.89% | 0 mm | 62.3 mph | compare → |
| 325/30R21 | 28.68" | -0.61% | +40 mm | 59.6 mph | compare → |
| 275/40R21 | 29.66" | +2.80% | -10 mm | 61.7 mph | compare → |
| 255/35R21 | 28.03" | -2.87% | -30 mm | 58.3 mph | compare → |
| 315/30R21 | 28.44" | -1.43% | +30 mm | 59.1 mph | compare → |
| 245/40R21 | 28.72" | -0.48% | -40 mm | 59.7 mph | compare → |
| 315/35R21 | 29.68" | +2.87% | +30 mm | 61.7 mph | compare → |
| 305/30R21 | 28.20" | -2.25% | +20 mm | 58.6 mph | compare → |
| 295/30R21 | 27.97" | -3.07% | +10 mm | 58.2 mph | compare → |
| 285/30R21 | 27.73" | -3.89% | 0 mm | 57.7 mph | compare → |
| 255/45R21 | 30.04" | +4.09% | -30 mm | 62.5 mph | compare → |
| 245/45R21 | 29.68" | +2.87% | -40 mm | 61.7 mph | compare → |
| 275/30R21 | 27.50" | -4.71% | -10 mm | 57.2 mph | compare → |
| 235/50R21 | 30.25" | +4.84% | -50 mm | 62.9 mph | calculate → |
| 355/25R21 | 27.99" | -3.00% | +70 mm | 58.2 mph | calculate → |
| 235/45R21 | 29.33" | +1.64% | -50 mm | 61.0 mph | calculate → |
| 335/30R21 | 28.91" | +0.20% | +50 mm | 60.1 mph | calculate → |
| 305/35R21 | 29.41" | +1.91% | +20 mm | 61.1 mph | calculate → |
| 345/30R21 | 29.15" | +1.02% | +60 mm | 60.6 mph | calculate → |
| 225/45R21 | 28.97" | +0.41% | -60 mm | 60.2 mph | calculate → |
| 345/25R21 | 27.79" | -3.68% | +60 mm | 57.8 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" | -0.60% | -40 mm | 59.6 mph | compare → |
| 255/45R20 common | 29.04" | +0.63% | -30 mm | 60.4 mph | compare → |
| 275/40R20 common | 28.66" | -0.67% | -10 mm | 59.6 mph | compare → |
| 315/35R20 common | 28.68" | -0.60% | +30 mm | 59.6 mph | compare → |
| 285/40R20 | 28.98" | +0.42% | 0 mm | 60.3 mph | compare → |
| 285/30R22 | 28.73" | -0.42% | 0 mm | 59.7 mph | compare → |
| 295/30R22 | 28.97" | +0.40% | +10 mm | 60.2 mph | compare → |
| 255/35R22 | 29.03" | +0.60% | -30 mm | 60.4 mph | calculate → |
| 335/25R22 | 28.59" | -0.90% | +50 mm | 59.5 mph | calculate → |
| 325/35R20 | 28.96" | +0.35% | +40 mm | 60.2 mph | calculate → |
| 355/25R22 | 28.99" | +0.46% | +70 mm | 60.3 mph | calculate → |
| 29x15.00R20 | 29.00" | +0.50% | +96 mm | 60.3 mph | calculate → |
| 29x18.00R20 | 29.00" | +0.50% | +172 mm | 60.3 mph | calculate → |
Try another size against 285/35R21
Questions
What size is 285/35R21 in inches?
285/35R21 is about 28.9" tall and 11.2" wide on a 21-inch rim — roughly a 29x11.00R21 in inch sizing.
What does 285/35R21 mean?
285 mm section width, sidewall 35% of the width (3.93"), radial construction, 21-inch rim.
What tire sizes are equivalent to 285/35R21?
On the same 21" rim, within 3% of the diameter: 335/30R21 (+0.20%), 225/45R21 (+0.41%), 245/40R21 (-0.48%), 255/40R21 (+0.61%), 325/30R21 (-0.61%), 295/35R21 (+0.96%).
How many revolutions per mile does a 285/35R21 tire make?
About 699 revolutions per mile (circumference 90.6").
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.