HUMMER · HX · Cold

Setting cold tyres on a HUMMER HX

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

34 / 34

Catalogue mid-points, front / rear · 2.2-2.4 / 2.2-2.4 bar

32-35 psi F · 32-35 psi R · 2.2-2.4 / 2.2-2.4 bar · 231/231 kPa

Cold means the HUMMER HX has stood at least three hours, or covered less than about a mile. Heat from a dual carriageway run is not the number you set. TPMS typically warns near 25 psi (about 25% below target). That is already a soft tyre, not a fill target.

Temperature and a cold gauge

Roughly 1 psi per 5–6 °C. The table uses 34 psi as a 20 °C baseline for this HX.

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

How to set the HX

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

HUMMER HX placard versus sidewall

If the HUMMER sticker is painted over, the handbook is next. This website is a map, not a replacement VIN label.

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

If your HUMMER HX no longer wears the OEM diameter, start at the row nearest 225/45R17 or 205/55R16 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	35	2.41	2.41	241	241	Sport 17-inch
205/55R16	34	34	2.34	2.34	234	234	Typical mid-compact OEM
245/40R18	36	36	2.48	2.48	248	248	Wide touring 18-inch
215/50R17	35	35	2.41	2.41	241	241	Plus-size 17-inch
185/65R15	33	33	2.28	2.28	228	228	Small / older car
225/50R17	35	35	2.41	2.41	241	241	Touring 17-inch
225/40R18	36	36	2.48	2.48	248	248	Low-profile 18-inch
195/65R15	34	34	2.34	2.34	234	234	Very common compact

PSI, bar and kPa

PSI-led conversions for the HUMMER HX 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

Load notes

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	36 psi / 2.48 bar

HUMMER notes

No special HUMMER exception: the HX 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 HUMMER HX 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 HX than nitrogen upsells.

Other HUMMER models

H1 H3 H2

Questions about this HX

What is that in bar and kPa for the HX?

Mid-points are about 2.31 bar (231 kPa) front and 2.31 bar (231 kPa) rear.

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, 205/55R16 and 245/40R18 as a planning band.

Is the sidewall number correct on a HUMMER HX?

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

Front versus rear on the HUMMER HX?

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.

What tyre pressure should a HUMMER HX 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