psi, bar and kPa
Bicycle pressures converted between psi, bar, kPa and kgf / cm², at the values people actually pump to.
Pump in whatever your gauge is marked in. The unit is not where the error comes from.
psi to bar, kPa and kgf / cm²
Bicycle pressures, at the values people actually pump to. Bar and kgf / cm² are close but not the same: one kgf / cm² is 0.9807 bar, about 2% under. Near enough to read across at a glance, far enough to matter if you pump to it.
Common bicycle pressures
| psi | bar | kPa | kgf/cm² |
|---|---|---|---|
| 20 | 1.38 | 138 | 1.41 |
| 25 | 1.72 | 172 | 1.76 |
| 30 | 2.07 | 207 | 2.11 |
| 35 | 2.41 | 241 | 2.46 |
| 40 | 2.76 | 276 | 2.81 |
| 45 | 3.10 | 310 | 3.16 |
| 50 | 3.45 | 345 | 3.52 |
| 60 | 4.14 | 414 | 4.22 |
| 70 | 4.83 | 483 | 4.92 |
| 80 | 5.52 | 552 | 5.62 |
| 100 | 6.89 | 689 | 7.03 |
One bar is 14.5038 psi, and one psi is 0.0689 bar. If you only remember one thing, remember that bar is roughly psi divided by 14.5, and that a 2 bar tire is a low-30s tire.
Your gauge decides, not your country
There is no correct unit. Pump in whatever your gauge is marked in, because the conversion is not where error comes from — the gauge is. A floor pump calibrated for car tires is vague at bicycle pressures in every unit equally.
Bar and kPa are the same measurement a thousand apart: 1 bar is 100 kPa. Gauges marked in kPa are common on digital units and rare on floor pumps. kgf / cm² turns up on older equipment, and it is the one pair here that is not interchangeable: treat its reading as bar and you stop 0.4–1.9 psi soft across this table — always soft, never over. Use the row above rather than reading one gauge as the other.
Converting exactly will not save a wrong number
Getting the conversion right is worth about a tenth of a psi. Getting the pressure right is worth several, and the two errors that dwarf any rounding are your pump’s own offset and a number that was never yours to begin with.
If your pump reads two psi high, every conversion you do is exact and every tire you pump is wrong by two. How Baró builds a number covers both — what goes into it, and the places it rests on us rather than on evidence.