235/45R17 · passenger car · kPa
235/45R17 tyre pressure in kPa
- Size
- 235/45R17
- Class
- passenger car
- Planning PSI
- 36
- Planning bar
- 2.48
kPa
248
2.48 bar · 36 psi · 100 kPa = 1 bar
235/45R17 · 36 psi · 2.48 bar · 248 kPa — estimates. Placard wins.
If the gauge only speaks kPa, 248 kPa is the sketch for this passenger car size. Fine-tune to the vehicle that actually wears 235/45R17. A 10 °C overnight drop takes roughly 1 psi (0.07 bar) off a closed 235/45R17. Low-profile {sz} does not want a “softer” pressure to recover ride. Stay at or slightly above the car’s original placard if load index is kept.
kPa, bar and PSI
Convert around the 235/45R17 band. 2.48 bar is about 36 psi — not 23, not 33 unless the maths says so.
| kPa | Bar | PSI |
|---|---|---|
| 221 | 2.21 | 32 |
| 228 | 2.28 | 33 |
| 234 | 2.34 | 34 |
| 241 | 2.41 | 35 |
| 248 | 2.48 | 36 |
| 255 | 2.55 | 37 |
| 262 | 2.62 | 38 |
| 269 | 2.69 | 39 |
| 276 | 2.76 | 40 |
| 283 | 2.83 | 41 |
| 290 | 2.90 | 42 |
| 296 | 2.96 | 43 |
| 303 | 3.03 | 44 |
| 310 | 3.10 | 45 |
| 317 | 3.17 | 46 |
| 324 | 3.24 | 47 |
| 331 | 3.31 | 48 |
Estimated 235/45R17 pressure by load
Load moves the rear first on a passenger car. If the factory placard already has a laden column, use that — not this sketch for 235/45R17.
| Condition | Front (est.) | Rear (est.) |
|---|---|---|
| Driver only / unladen | 36 psi / 2.48 bar / 248 kPa | 36 psi / 2.48 bar / 248 kPa |
| Typical occupancy | 36 psi / 2.48 bar / 248 kPa | 37 psi / 2.55 bar / 255 kPa |
| Motorway + luggage (sketch) | 37 psi / 2.55 bar / 255 kPa | 38 psi / 2.62 bar / 262 kPa |
What 235/45R17 means
A 235/45R17 on a passenger car is a geometry. Two cars can share the size and disagree on PSI because mass and axle split differ.
Wide 17-inch sport. Rim diameter 17 in; section 235 mm. Estimates on this page assume a typical load index for the passenger car class.
Placard versus sidewall
This website maps size searches such as “235/45R17 psi”. It does not replace the VIN label. If the two disagree, the label wins.
Temperature drift
Roughly 1 psi per 5–6 °C. The table uses 36 psi as a 20 °C baseline for 235/45R17.
| Ambient | Gauge | Bar | kPa | Note |
|---|---|---|---|---|
| −5 °C (hard frost) | 33 psi | 2.28 bar | 228 kPa | Gauge reads low; do not overfill once warm |
| 0 °C | 34 psi | 2.34 bar | 234 kPa | Gauge reads low; do not overfill once warm |
| 8 °C (UK winter morning) | 35 psi | 2.41 bar | 241 kPa | Gauge reads low; do not overfill once warm |
| 20 °C (set cold here) | 36 psi | 2.48 bar | 248 kPa | Baseline for this size sketch |
| 30 °C | 38 psi | 2.62 bar | 262 kPa | Do not bleed a hot 235/45R17 |
| 38 °C (heatwave tarmac) | 39 psi | 2.69 bar | 269 kPa | Do not bleed a hot 235/45R17 |
How to set 235/45R17
- Measure before the school run, not after the motorway.
- Write LF / RF / RR / RL. Do not keep 235/45R17 numbers in your head.
- Add air in short bursts toward the placard, using 36 psi only as a map.
- If one 235/45R17 is 4 psi down, hunt for a nail before you blame the weather.
- Log date, ambient temperature and the four readings.
Cars often seen on 235/45R17
These catalogue models are often seen on 235/45R17 or a close OEM neighbour. Open the vehicle chart for axle-specific PSI and bar.
Keep 235/45R17 on the printed band for that car; 36 psi is a size sketch, not a second VIN label.
Questions about 235/45R17
When does TPMS warn on 235/45R17?
Direct TPMS typically flags about 25% below target — near 27 psi if you were aiming at 36. Fill to the sticker, not to the lamp.
Is 235/45R17 the same as a plus-size swap?
Only if that is the size you fitted. Overall diameter should stay close to OEM. Pressure still follows the car, with load index at or above original.
What is 235/45R17 in kPa?
248 kPa is the planning midpoint (100 kPa = 1 bar). 255 kPa is one PSI higher.
Should I bleed pressure after a motorway run?
No. Heat raises the gauge. Set cold only. Bleeding a hot tyre leaves it low the next morning.
Can I run 235/45R17 at a lower pressure for comfort?
Not as a habit. A soft 235/45R17 cooks the shoulders and dulls steering. Keep load index and stay on the placard.
Handbook: placard · bar vs PSI · cold inflation · all sizes