AC · Ace · Front
AC Ace front tyre pressure
- Drivetrain
- front-wheel drive
- Body
- passenger car
- PSI F / R
- 32-35 / 32-35
- Bar F / R
- 2.2-2.4 / 2.2-2.4
psi front
34
2.31 bar · 231 kPa at the steering axle
32-35 psi F · 32-35 psi R · 2.2-2.4 / 2.2-2.4 bar · 231/231 kPa
A 3 psi miss on one front corner of this Ace shows up as a wander before the TPMS lamp bothers you. Target 34 psi (2.31 bar) cold. Under-inflation cooks the shoulders of a Ace; over-inflation wears the centre rib and bangs every cat’s eye.
AC Ace placard versus sidewall
The tyre-information placard on a AC Ace 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 (225/45R17 and others)
Planning cold pressures for sizes often seen on a passenger car. This Ace sample opens with 225/45R17, then 245/40R18 and 225/50R17.
| Tyre size | Front PSI | Rear PSI | Front bar | Rear bar | Front kPa | Rear kPa | Note |
|---|---|---|---|---|---|---|---|
| 225/45R17 | 35 | — | 2.41 | — | 241 | — | Sport 17-inch |
| 245/40R18 | 36 | — | 2.48 | — | 248 | — | Wide touring 18-inch |
| 225/50R17 | 35 | — | 2.41 | — | 241 | — | Touring 17-inch |
| 205/55R16 | 34 | — | 2.34 | — | 234 | — | Typical mid-compact OEM |
| 185/65R15 | 33 | — | 2.28 | — | 228 | — | Small / older car |
| 225/40R18 | 36 | — | 2.48 | — | 248 | — | Low-profile 18-inch |
| 215/50R17 | 35 | — | 2.41 | — | 241 | — | Plus-size 17-inch |
| 215/55R16 | 34 | — | 2.34 | — | 234 | — | Slightly wider 16-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 | 34 psi / 2.34 bar | 35 psi / 2.41 bar |
| Motorway + luggage | 35 psi / 2.41 bar | 37 psi / 2.55 bar |
Steering feel on the Ace lives on this axle. Do not drop front pressure to “soften” a plus-size 225/50R17; you will roll the sidewall in a roundabout.
How to set the Ace
- Measure before the school run, not after the M25.
- Write LF / RF / RR / RL. Do not keep Ace 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 AC Ace 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 Ace.
| 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 |
AC notes
No special AC exception: the Ace 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 AC Ace 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 AC sticker and this page disagree, the sticker wins.
Other AC models
Questions about this Ace
What is that in bar and kPa for the Ace?
Mid-points are about 2.31 bar (231 kPa) front and 2.31 bar (231 kPa) rear.
When does TPMS warn on a AC Ace?
Direct TPMS typically flags about 25% below placard — near 25 psi on this row. Fill to the sticker, not to the lamp.
Is the sidewall number correct on a AC Ace?
No. Sidewall PSI is a maximum. The Ace placard is the operating target, near 32-35/32-35 psi.
How often should I check a Ace?
Monthly, before a long trip, and after a 10 °C weather swing. Include a full-size spare.
What tyre pressure should a AC Ace 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.
Handbook: placard · bar vs PSI · front vs rear · cold inflation