235/55R18 · SUV / crossover · kPa
235/55R18 tyre pressure in kPa
- Size
- 235/55R18
- Class
- SUV / crossover
- Planning PSI
- 35
- Planning bar
- 2.41
kPa
241
2.41 bar · 35 psi · 100 kPa = 1 bar
235/55R18 · 35 psi · 2.41 bar · 241 kPa — estimates. Placard wins.
If the gauge only speaks kPa, 241 kPa is the sketch for this SUV / crossover size. Fine-tune to the vehicle that actually wears 235/55R18. A 10 °C overnight drop takes roughly 1 psi (0.07 bar) off a closed 235/55R18.
kPa, bar and PSI
Use the table, then set a cold gauge. 241 kPa is 100 × 2.41 bar on this size.
| kPa | Bar | PSI |
|---|---|---|
| 214 | 2.14 | 31 |
| 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 |
Estimated 235/55R18 pressure by load
Plus-sizing to 235/55R18 from a taller OEM tyre usually keeps the same placard if the load index is equal or higher.
| Condition | Front (est.) | Rear (est.) |
|---|---|---|
| Driver only / unladen | 35 psi / 2.41 bar / 241 kPa | 35 psi / 2.41 bar / 241 kPa |
| Typical occupancy | 35 psi / 2.41 bar / 241 kPa | 36 psi / 2.48 bar / 248 kPa |
| Motorway + luggage (sketch) | 36 psi / 2.48 bar / 248 kPa | 37 psi / 2.55 bar / 255 kPa |
What 235/55R18 means
A 235/55R18 on a SUV / crossover is a geometry. Two cars can share the size and disagree on PSI because mass and axle split differ.
Plus-size mid-SUV 18-inch. Rim diameter 18 in; section 235 mm. Estimates on this page assume a typical load index for the SUV / crossover class.
Placard versus sidewall
If a forum says “all 235/55R18 run 35 psi”, ignore it. A Qashqai and a Golf can share a size and not share a sticker.
Temperature drift
Roughly 1 psi per 5–6 °C. The table uses 35 psi as a 20 °C baseline for 235/55R18.
| Ambient | Gauge | Bar | kPa | Note |
|---|---|---|---|---|
| −5 °C (hard frost) | 32 psi | 2.21 bar | 221 kPa | Gauge reads low; do not overfill once warm |
| 0 °C | 33 psi | 2.28 bar | 228 kPa | Gauge reads low; do not overfill once warm |
| 8 °C (UK winter morning) | 34 psi | 2.34 bar | 234 kPa | Gauge reads low; do not overfill once warm |
| 20 °C (set cold here) | 35 psi | 2.41 bar | 241 kPa | Baseline for this size sketch |
| 30 °C | 37 psi | 2.55 bar | 255 kPa | Do not bleed a hot 235/55R18 |
| 38 °C (heatwave tarmac) | 38 psi | 2.62 bar | 262 kPa | Do not bleed a hot 235/55R18 |
How to set 235/55R18
- Park so the 235/55R18 tyres are cold (three hours, or less than about a mile).
- Read the door-pillar placard for that car — not the 235/55R18 sidewall maximum.
- If the sticker is missing, 35 psi / 2.41 bar is only a SUV / crossover planning figure for this size.
- Set all four with a calibrated gauge. A 3 psi miss on one corner shows up as a wander.
- Refit valve caps and reset TPMS if the handbook asks for a relearn.
Cars often seen on 235/55R18
These catalogue models are often seen on 235/55R18 or a close OEM neighbour. Open the vehicle chart for axle-specific PSI and bar.
Keep 235/55R18 on the printed band for that car; 35 psi is a size sketch, not a second VIN label.
Questions about 235/55R18
What is 235/55R18 in bar?
35 psi is 2.41 bar. Add a tenth of a bar if the placard’s laden column is higher, which is common on vans that wear this size.
What PSI should 235/55R18 tyres be?
A SUV / crossover planning figure is about 35 psi cold (2.41 bar / 241 kPa). Confirm on the vehicle placard — two cars can share 235/55R18 and not share a sticker.
Is 235/55R18 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.
When does TPMS warn on 235/55R18?
Direct TPMS typically flags about 25% below target — near 26 psi if you were aiming at 35. Fill to the sticker, not to the lamp.
What is 235/55R18 in kPa?
241 kPa is the planning midpoint (100 kPa = 1 bar). 248 kPa is one PSI higher.
Handbook: placard · bar vs PSI · cold inflation · all sizes