Porsche · Boxster · Rear
Porsche Boxster rear tyre pressure
- 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
psi rear
34
2.31 bar · 231 kPa at the rear axle
32-35 psi F · 32-35 psi R · 2.2-2.4 / 2.2-2.4 bar · 231/231 kPa
The rear of a passenger car takes passengers, luggage and, on vans, payload. Catalogue rear pressure on the Porsche Boxster is 32-35 psi / 2.2-2.4 bar. Size estimates on this page include 245/40R18, 275/35R18 and 225/45R17 — interpolated from the catalogue midpoint, not a second factory sticker.
Porsche Boxster placard versus sidewall
The tyre-information placard on a Porsche Boxster sits on the driver’s door pillar (sometimes the fuel-filler flap). Catalogue figures here are a general band: 32-35 / 32-35 psi.
Estimated pressure by tyre size (245/40R18 and others)
245/40R18 is the first planning size here. 225/45R17 is usually the plus-size or LT step. Keep load index at or above original equipment.
| Tyre size | Front PSI | Rear PSI | Front bar | Rear bar | Front kPa | Rear kPa | Note |
|---|---|---|---|---|---|---|---|
| 245/40R18 | — | 36 | — | 2.48 | — | 248 | Square-ish sport |
| 275/35R18 | — | 37 | — | 2.55 | — | 255 | Wide rear |
| 225/45R17 | — | 35 | — | 2.41 | — | 241 | Front sport size |
| 255/40R17 | — | 36 | — | 2.48 | — | 248 | Rear stagger 17-inch |
| 255/35R18 | — | 36 | — | 2.48 | — | 248 | Rear stagger 18-inch |
| 275/30R19 | — | 37 | — | 2.55 | — | 255 | Rear 19-inch |
| 235/35R19 | — | 36 | — | 2.48 | — | 248 | Front 19-inch |
| 225/40R18 | — | 35 | — | 2.41 | — | 241 | Front 18-inch |
Pressure against load
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 | 35 psi / 2.41 bar | 36 psi / 2.48 bar |
| Motorway + luggage | 36 psi / 2.48 bar | 37 psi / 2.55 bar |
A family passenger car with a boot full of luggage should use the laden rear figure if Ford, VW or Mercedes printed one. Otherwise the modest steps in the load table are only a sketch for this Boxster.
How to set the Boxster
- Measure before the school run, not after the M25.
- Write LF / RF / RR / RL. Do not keep Boxster numbers in your head.
- Add air in short bursts toward 34 psi (2.31 bar) front and 34 psi rear.
- If one corner is 4 psi down, hunt for a nail before you blame the weather.
- Log date, ambient temperature and the four readings.
PSI, bar and kPa
PSI-led conversions for the Porsche Boxster band (32-35 / 32-35).
| PSI | Bar | kPa |
|---|---|---|
| 30 | 2.07 | 207 |
| 32 | 2.21 | 221 |
| 33 | 2.28 | 228 |
| 33.5 | 2.31 | 231 |
| 35 | 2.41 | 241 |
| 36 | 2.48 | 248 |
| 38 | 2.62 | 262 |
| 40 | 2.76 | 276 |
| 44 | 3.03 | 303 |
| 50 | 3.45 | 345 |
| 60 | 4.14 | 414 |
Temperature drift
Roughly 1 psi per 5–6 °C. The table uses 34 psi as a 20 °C baseline for this Boxster.
| 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 |
Porsche notes
No special Porsche exception: the Boxster uses the door-pillar placard. Size estimates on this page only help if you have left the original load index behind.
Spare and inflator kit
A matching full-size spare on the Porsche Boxster 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.
Keep the Porsche Boxster on the printed band; use 245/40R18 and 225/45R17 only as a map for non-OEM wheels.
Other Porsche models
Questions about this Boxster
What is that in bar and kPa for the Boxster?
Mid-points are about 2.31 bar (231 kPa) front and 2.31 bar (231 kPa) rear.
What tyre pressure should a Porsche Boxster 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.
How often should I check a Boxster?
Monthly, before a long trip, and after a 10 °C weather swing. Include a full-size spare.
Front versus rear on the Porsche Boxster?
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.
Is the sidewall number correct on a Porsche Boxster?
No. Sidewall PSI is a maximum. The Boxster placard is the operating target, near 32-35/32-35 psi.
Handbook: placard · bar vs PSI · front vs rear · cold inflation