Ruf · RT 12S · Rear
Ruf RT 12S rear 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 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 Ruf RT 12S is 32-35 psi / 2.2-2.4 bar. TPMS typically warns near 25 psi (about 25% below target). That is already a soft tyre, not a fill target.
Ruf RT 12S placard versus sidewall
The tyre-information placard on a Ruf RT 12S 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 (225/50R17 and others)
225/50R17 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 |
|---|---|---|---|---|---|---|---|
| 225/50R17 | — | 35 | — | 2.41 | — | 241 | Touring 17-inch |
| 205/55R16 | — | 34 | — | 2.34 | — | 234 | Typical mid-compact OEM |
| 225/45R17 | — | 35 | — | 2.41 | — | 241 | Sport 17-inch |
| 225/40R18 | — | 36 | — | 2.48 | — | 248 | Low-profile 18-inch |
| 195/65R15 | — | 34 | — | 2.34 | — | 234 | Very common compact |
| 205/60R16 | — | 34 | — | 2.34 | — | 234 | Taller 16-inch |
| 215/55R16 | — | 35 | — | 2.41 | — | 241 | Slightly wider 16-inch |
| 215/50R17 | — | 35 | — | 2.41 | — | 241 | Plus-size 17-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 | 38 psi / 2.62 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 RT 12S.
How to set the RT 12S
- Measure before the school run, not after the M25.
- Write LF / RF / RR / RL. Do not keep RT 12S 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 Ruf RT 12S 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 RT 12S.
| 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 |
Ruf notes
No special Ruf exception: the RT 12S 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 Ruf RT 12S 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.
A cheap gauge and a monthly habit will do more for this RT 12S than nitrogen upsells.
Other Ruf models
Questions about this RT 12S
Front versus rear on the Ruf RT 12S?
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.
When does TPMS warn on a Ruf RT 12S?
Direct TPMS typically flags about 25% below placard — near 25 psi on this row. Fill to the sticker, not to the lamp.
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 PSI if I plus-size toward 225/45R17?
Keep load index at or above OEM. Low-profile sizes usually stay at or slightly above the placard. Use 225/50R17, 205/55R16 and 225/45R17 as a planning band.
What is that in bar and kPa for the RT 12S?
Mid-points are about 2.31 bar (231 kPa) front and 2.31 bar (231 kPa) rear.
Handbook: placard · bar vs PSI · front vs rear · cold inflation