2020 BMW X3 M tire size
Most common factory size
P255/40R21
- Factory sizes
- 1
- Across 2 trims
- Diameter
- 29.03 in
- Revs per mile
- 695
Tire sizes by trim
Source marks: one source
| Size | Trims | Width, mm | Sidewall, % of width | Rim, in | Diameter, in | Sidewall, in | Revs per mile |
|---|---|---|---|---|---|---|---|
| P255/40R21 | All 2 trims | 255 | 40 | 21 | 29.03 | 4.02 | 695 |
What P255/40R21 means
| Part | Number | Meaning |
|---|---|---|
| Type | P | Passenger car tire. |
| Width | 255 mm | Tread width. 10.0 in. |
| Sidewall | 40 | Sidewall height is 40% of the width. |
| Construction | R | Radial tire. |
| Rim | 21 in | Fits 21 in wheels. |
Other sizes that fit
Within 3% of the stock diameter. A common shop guideline, not a maker spec.
| Size | Rim, in | Diameter, in | Change | Speedo reads at 60 mph |
|---|---|---|---|---|
| 255/35R22 | 22 | 29.03 | -0.0% | 60.0 mph |
| 255/45R20 | 20 | 29.04 | +0.0% | 60.0 mph |
| 285/40R20 | 20 | 28.98 | -0.2% | 60.1 mph |
| 225/45R21 | 21 | 28.97 | -0.2% | 60.1 mph |
| 325/35R20 | 20 | 28.96 | -0.3% | 60.2 mph |
| 295/35R21 | 21 | 29.13 | +0.3% | 59.8 mph |
| 285/35R21 | 21 | 28.85 | -0.6% | 60.4 mph |
| 235/50R20 | 20 | 29.25 | +0.8% | 59.5 mph |
Checked against 292 factory sizes listed for 2009-2027 US models.
What this cannot tell you
Tire pressure is on the driver door sticker. Not in this data.
Optional wheel packages may differ.
- Two or more sources agree
- One source
- Model-level or estimate
- Sources differ