225/45R17 · passenger car · Overview
225/45R17: PSI, bar and kPa
- Size
- 225/45R17
- Class
- passenger car
- Planning PSI
- 35
- Planning bar
- 2.41
225/45R17
35 psi / 2.41 bar
241 kPa · estimates for this size class
225/45R17 · 35 psi · 2.41 bar · 241 kPa — estimates. Placard wins.
225/45R17 is a passenger car size (225 mm section, 45 % aspect, 17-inch rim). A planning cold figure around 35 psi / 2.41 bar / 241 kPa is a starting map, not a second factory sticker. The default 17-inch sport / saloon size. These rows are estimates interpolated for the size, not OEM for a named VIN. 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.
What 225/45R17 means
225/45R17 means a 225 millimetre section width, a sidewall that is 45 percent of that width, on a 17-inch rim. The R is radial construction.
The default 17-inch sport / saloon size. Rim diameter 17 in; section 225 mm. Estimates on this page assume a typical load index for the passenger car class.
Estimated 225/45R17 pressure by load
These 225/45R17 load steps are ± a few PSI from 35. They are not a licence to ignore a printed second column on a van or estate.
| 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 |
PSI, bar and kPa
Convert around the 225/45R17 band. 2.41 bar is about 35 psi — not 23, not 33 unless the maths says so.
| PSI | Bar | kPa |
|---|---|---|
| 31 | 2.14 | 214 |
| 32 | 2.21 | 221 |
| 33 | 2.28 | 228 |
| 34 | 2.34 | 234 |
| 35 | 2.41 | 241 |
| 36 | 2.48 | 248 |
| 37 | 2.55 | 255 |
| 38 | 2.62 | 262 |
| 39 | 2.69 | 269 |
| 40 | 2.76 | 276 |
| 41 | 2.83 | 283 |
| 42 | 2.90 | 290 |
| 43 | 2.96 | 296 |
| 44 | 3.03 | 303 |
| 45 | 3.10 | 310 |
| 46 | 3.17 | 317 |
| 47 | 3.24 | 324 |
Placard versus sidewall
This website maps size searches such as “225/45R17 psi”. It does not replace the VIN label. If the two disagree, the label wins.
Cars often seen on 225/45R17
These catalogue models are often seen on 225/45R17 or a close OEM neighbour. Open the vehicle chart for axle-specific PSI and bar.
How to set 225/45R17
- Measure before the school run, not after the motorway.
- Write LF / RF / RR / RL. Do not keep 225/45R17 numbers in your head.
- Add air in short bursts toward the placard, using 35 psi only as a map.
- If one 225/45R17 is 4 psi down, hunt for a nail before you blame the weather.
- Log date, ambient temperature and the four readings.
Temperature drift
Roughly 1 psi per 5–6 °C. The table uses 35 psi as a 20 °C baseline for 225/45R17.
| 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 225/45R17 |
| 38 °C (heatwave tarmac) | 38 psi | 2.62 bar | 262 kPa | Do not bleed a hot 225/45R17 |
If the door sticker and this 225/45R17 page disagree, the sticker wins.
Questions about 225/45R17
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.
What is 225/45R17 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 is 225/45R17 in kPa?
241 kPa is the planning midpoint (100 kPa = 1 bar). 248 kPa is one PSI higher.
Is 225/45R17 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 PSI should 225/45R17 tyres be?
A passenger car planning figure is about 35 psi cold (2.41 bar / 241 kPa). Confirm on the vehicle placard — two cars can share 225/45R17 and not share a sticker.
Handbook: placard · bar vs PSI · cold inflation · all sizes