Oldtimer · Humber · Rear

Rear axle PSI and bar on the Oldtimer Humber

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

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 Oldtimer Humber is 32-35 psi / 2.2-2.4 bar. Size estimates on this page include 225/45R17, 215/50R17 and 245/40R18 — interpolated from the catalogue midpoint, not a second factory sticker.

Oldtimer Humber placard versus sidewall

Sidewall PSI is a carcass maximum. Recommended operating pressure for this Humber is the pillar sticker, near 34/34 psi.

Estimated pressure by tyre size (225/45R17 and others)

If your Oldtimer Humber no longer wears the OEM diameter, start at the row nearest 225/45R17 or 215/50R17 and confirm with the tyre maker’s load table.

Tyre size	Front PSI	Rear PSI	Front bar	Rear bar	Front kPa	Rear kPa	Note
225/45R17	—	35	—	2.41	—	241	Sport 17-inch
215/50R17	—	35	—	2.41	—	241	Plus-size 17-inch
245/40R18	—	36	—	2.48	—	248	Wide touring 18-inch
185/65R15	—	33	—	2.28	—	228	Small / older car
205/60R16	—	34	—	2.34	—	234	Taller 16-inch
225/50R17	—	35	—	2.41	—	241	Touring 17-inch
215/55R16	—	35	—	2.41	—	241	Slightly wider 16-inch
225/40R18	—	36	—	2.48	—	248	Low-profile 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	34 psi / 2.34 bar	35 psi / 2.41 bar
Motorway + luggage	35 psi / 2.41 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 Humber.

How to set the Humber

Measure before the school run, not after the M25.
Write LF / RF / RR / RL. Do not keep Humber 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 Oldtimer Humber 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 Humber.

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

Oldtimer notes

No special Oldtimer exception: the Humber 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 Oldtimer Humber 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 Oldtimer sticker and this page disagree, the sticker wins.

Other Oldtimer models

Arnolt Abarth Aurora Alfa Romeo Autobianchi Auburn ASC Armstrong Siddeley

Questions about this Humber

Front versus rear on the Oldtimer Humber?

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.

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.

Is the sidewall number correct on a Oldtimer Humber?

No. Sidewall PSI is a maximum. The Humber placard is the operating target, near 32-35/32-35 psi.

What tyre pressure should a Oldtimer Humber 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.

What PSI if I plus-size toward 245/40R18?

Keep load index at or above OEM. Low-profile sizes usually stay at or slightly above the placard. Use 225/45R17, 215/50R17 and 245/40R18 as a planning band.

Handbook: placard · bar vs PSI · front vs rear · cold inflation