355/25R21 tire size
355/25R21 is a metric size: 28.0" tall, 14.0" wide, on a 21" rim — about a 28x14.00R21. The sidewall is 3.5" and the tire turns 721 times per mile.
355/25R21 specs
| Overall diameter (height) | 27.99" · 711 mm |
|---|---|
| Section width | 13.98" · 355 mm |
| Sidewall height | 3.49" · 89 mm (25% of width) |
| Rim diameter | 21" |
| Circumference | 87.93" · 2.233 m |
| Revolutions per mile | 721 (448 per km) |
| Inch (flotation) equivalent | 28x14.00R21 |
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" | +4.85% | -90 mm | 62.9 mph | calculate → |
| 275/35R21 common | 28.58" | +2.11% | -80 mm | 61.3 mph | calculate → |
| 295/35R21 | 29.13" | +4.08% | -60 mm | 62.4 mph | calculate → |
| 255/40R21 | 29.03" | +3.73% | -100 mm | 62.2 mph | calculate → |
| 265/35R21 | 28.30" | +1.13% | -90 mm | 60.7 mph | calculate → |
| 245/35R21 | 27.75" | -0.84% | -110 mm | 59.5 mph | calculate → |
| 325/30R21 | 28.68" | +2.46% | -30 mm | 61.5 mph | calculate → |
| 255/35R21 | 28.03" | +0.14% | -100 mm | 60.1 mph | calculate → |
| 315/30R21 | 28.44" | +1.62% | -40 mm | 61.0 mph | calculate → |
| 285/35R21 | 28.85" | +3.09% | -70 mm | 61.9 mph | calculate → |
| 245/40R21 | 28.72" | +2.60% | -110 mm | 61.6 mph | calculate → |
| 295/30R21 | 27.97" | -0.07% | -60 mm | 60.0 mph | calculate → |
| 305/30R21 | 28.20" | +0.77% | -50 mm | 60.5 mph | calculate → |
| 285/30R21 | 27.73" | -0.91% | -70 mm | 59.5 mph | calculate → |
| 275/30R21 | 27.50" | -1.76% | -80 mm | 58.9 mph | calculate → |
| 255/30R21 | 27.02" | -3.45% | -100 mm | 57.9 mph | calculate → |
| 235/45R21 | 29.33" | +4.78% | -120 mm | 62.9 mph | calculate → |
| 295/25R21 | 26.81" | -4.22% | -60 mm | 57.5 mph | calculate → |
| 335/30R21 | 28.91" | +3.31% | -20 mm | 62.0 mph | calculate → |
| 265/30R21 | 27.26" | -2.60% | -90 mm | 58.4 mph | calculate → |
| 345/30R21 | 29.15" | +4.15% | -10 mm | 62.5 mph | calculate → |
| 345/25R21 | 27.79" | -0.70% | -10 mm | 59.6 mph | calculate → |
| 325/25R21 | 27.40" | -2.11% | -30 mm | 58.7 mph | calculate → |
| 225/45R21 | 28.97" | +3.52% | -130 mm | 62.1 mph | calculate → |
| 305/25R21 | 27.00" | -3.52% | -50 mm | 57.9 mph | calculate → |
| 245/30R21 | 26.79" | -4.29% | -110 mm | 57.4 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 | |
|---|---|---|---|---|---|
| 245/40R20 common | 27.72" | -0.97% | -110 mm | 59.4 mph | calculate → |
| 255/40R20 common | 28.03" | +0.15% | -100 mm | 60.1 mph | calculate → |
| 285/35R20 common | 27.85" | -0.48% | -70 mm | 59.7 mph | calculate → |
| 295/35R20 | 28.13" | +0.51% | -60 mm | 60.3 mph | calculate → |
| 255/30R22 | 28.02" | +0.13% | -100 mm | 60.1 mph | calculate → |
| 295/25R22 | 27.81" | -0.65% | -60 mm | 59.6 mph | calculate → |
| 265/30R22 | 28.26" | +0.97% | -90 mm | 60.6 mph | calculate → |
| 335/30R20 | 27.91" | -0.27% | -20 mm | 59.8 mph | calculate → |
| 345/30R20 | 28.15" | +0.58% | -10 mm | 60.3 mph | calculate → |
| 245/30R22 | 27.79" | -0.72% | -110 mm | 59.6 mph | calculate → |
| 315/25R22 | 28.20" | +0.76% | -40 mm | 60.5 mph | calculate → |
| 305/25R22 | 28.00" | +0.06% | -50 mm | 60.0 mph | calculate → |
| 225/45R20 | 27.97" | -0.06% | -130 mm | 60.0 mph | calculate → |
| 155/65R20 | 27.93" | -0.20% | -200 mm | 59.9 mph | calculate → |
| 165/60R20 | 27.80" | -0.69% | -190 mm | 59.6 mph | calculate → |
Try another size against 355/25R21
Questions
What size is 355/25R21 in inches?
355/25R21 is about 28.0" tall and 14.0" wide on a 21-inch rim — roughly a 28x14.00R21 in inch sizing.
What does 355/25R21 mean?
355 mm section width, sidewall 25% of the width (3.49"), radial construction, 21-inch rim.
What tire sizes are equivalent to 355/25R21?
On the same 21" rim, within 3% of the diameter: 295/30R21 (-0.07%), 255/35R21 (+0.14%), 345/25R21 (-0.70%), 305/30R21 (+0.77%), 245/35R21 (-0.84%), 285/30R21 (-0.91%).
How many revolutions per mile does a 355/25R21 tire make?
About 721 revolutions per mile (circumference 87.9").
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.