BMW · 128 · Bar
Recommended bar for a BMW 128
- Drivetrain
- rear-wheel drive
- Body
- passenger car
- PSI F / R
- 32-35 / 32-35
- Bar F / R
- 2.2-2.4 / 2.2-2.4
bar
2.31 / 2.31
32-35 / 32-35 psi · 231 / 231 kPa
32-35 psi F · 32-35 psi R · 2.2-2.4 / 2.2-2.4 bar · 231/231 kPa
2.3 bar is not 23 psi. On this 128 2.2-2.4 bar converts to about 32-35 psi. Use the table, not a guess. TPMS typically warns near 25 psi (about 25% below target). That is already a soft tyre, not a fill target.
Bar, PSI and kPa
Bar-led conversions around the BMW 128. 2.2-2.4 bar is not “32-35 divided by ten”.
| Bar | PSI | kPa |
|---|---|---|
| 2.07 | 30 | 207 |
| 2.21 | 32 | 221 |
| 2.28 | 33 | 228 |
| 2.31 | 33.5 | 231 |
| 2.41 | 35 | 241 |
| 2.48 | 36 | 248 |
| 2.62 | 38 | 262 |
| 2.76 | 40 | 276 |
| 3.03 | 44 | 303 |
| 3.45 | 50 | 345 |
| 4.14 | 60 | 414 |
BMW 128 placard versus sidewall
Sidewall PSI is a carcass maximum. Recommended operating pressure for this 128 is the pillar sticker, near 34/34 psi.
Estimated pressure by tyre size (225/45R17 and others)
Planning cold pressures for sizes often seen on a passenger car. This 128 sample opens with 225/45R17, then 225/40R18 and 205/60R16.
| Tyre size | Front PSI | Rear PSI | Front bar | Rear bar | Front kPa | Rear kPa | Note |
|---|---|---|---|---|---|---|---|
| 225/45R17 | 35 | 35 | 2.41 | 2.41 | 241 | 241 | Sport 17-inch |
| 225/40R18 | 36 | 36 | 2.48 | 2.48 | 248 | 248 | Low-profile 18-inch |
| 205/60R16 | 34 | 34 | 2.34 | 2.34 | 234 | 234 | Taller 16-inch |
| 215/50R17 | 35 | 35 | 2.41 | 2.41 | 241 | 241 | Plus-size 17-inch |
| 205/55R16 | 34 | 34 | 2.34 | 2.34 | 234 | 234 | Typical mid-compact OEM |
| 185/65R15 | 33 | 33 | 2.28 | 2.28 | 228 | 228 | Small / older car |
| 195/65R15 | 34 | 34 | 2.34 | 2.34 | 234 | 234 | Very common compact |
| 225/50R17 | 35 | 35 | 2.41 | 2.41 | 241 | 241 | Touring 17-inch |
Load notes
Load moves the rear of a passenger car first. If the factory placard already has a “laden” column, use that instead of these sketches.
| Condition | Front (est.) | Rear (est.) |
|---|---|---|
| Driver only | 34 psi / 2.34 bar | 34 psi / 2.34 bar |
| Full occupancy | 34 psi / 2.34 bar | 35 psi / 2.41 bar |
| Motorway + luggage | 35 psi / 2.41 bar | 37 psi / 2.55 bar |
How to set the 128
- Park the BMW 128 for at least three hours (cold tyres).
- Use a calibrated gauge, not the only meter on a forecourt hose.
- Set the placard for that axle — about 32-35 psi / 2.2-2.4 bar front and 32-35 psi / 2.2-2.4 bar rear on this catalogue row.
- Recheck all four. A 2 psi miss on a rear-wheel drive 128 is enough to feel a pull.
- Refit valve caps and reset TPMS if the handbook asks for a relearn.
Temperature drift
Roughly 1 psi per 5–6 °C. The table uses 34 psi as a 20 °C baseline for this 128.
| Ambient | Gauge (front mid) | Bar | kPa | Note |
|---|---|---|---|---|
| −5 °C (hard frost) | 31 psi | 2.14 bar | 214 kPa | Gauge reads low; do not overfill once warm |
| 0 °C | 32 psi | 2.21 bar | 221 kPa | Gauge reads low; do not overfill once warm |
| 8 °C (UK winter morning) | 33 psi | 2.28 bar | 228 kPa | Gauge reads low; do not overfill once warm |
| 20 °C (set cold here) | 34 psi | 2.34 bar | 234 kPa | Baseline |
| 30 °C | 36 psi | 2.48 bar | 248 kPa | Do not bleed a hot tyre |
| 38 °C (heatwave tarmac) | 37 psi | 2.55 bar | 255 kPa | Do not bleed a hot tyre |
BMW notes
BMW run-flats still want the placard. Comfort settings in the iDrive do not replace the door-pillar figure on this 128.
Spare and inflator kit
A matching full-size spare on the BMW 128 usually follows the higher axle (often the rear, near 32-35 psi). A space-saver is commonly 60 psi / 4.1 bar — read that tyre’s own sidewall. An inflator kit is not a spare; check the sealant date.
If the BMW sticker and this page disagree, the sticker wins.
Other BMW models
Questions about this 128
Front versus rear on the BMW 128?
This row is 32-35 F / 32-35 R. Even when they match, a laden rear can justify a higher number if the sticker prints one.
When does TPMS warn on a BMW 128?
Direct TPMS typically flags about 25% below placard — near 25 psi on this row. Fill to the sticker, not to the lamp.
What tyre pressure should a BMW 128 use?
Catalogue reference is 32-35 psi front and 32-35 psi rear (2.2-2.4 / 2.2-2.4 bar), cold. Confirm on the door-pillar placard.
What is that in bar and kPa for the 128?
Mid-points are about 2.31 bar (231 kPa) front and 2.31 bar (231 kPa) rear.
What PSI if I plus-size toward 205/60R16?
Keep load index at or above OEM. Low-profile sizes usually stay at or slightly above the placard. Use 225/45R17, 225/40R18 and 205/60R16 as a planning band.
Handbook: placard · bar vs PSI · front vs rear · cold inflation