Martin Motors · CoolCar · Rear

Rear axle PSI and bar on the Martin Motors CoolCar

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 Martin Motors CoolCar is 32-35 psi / 2.2-2.4 bar. Size estimates on this page include 185/65R15, 195/65R15 and 215/50R17 — interpolated from the catalogue midpoint, not a second factory sticker.

Martin Motors CoolCar placard versus sidewall

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

Estimated pressure by tyre size (185/65R15 and others)

If your Martin Motors CoolCar no longer wears the OEM diameter, start at the row nearest 185/65R15 or 195/65R15 and confirm with the tyre maker’s load table.

Tyre size	Front PSI	Rear PSI	Front bar	Rear bar	Front kPa	Rear kPa	Note
185/65R15	—	33	—	2.28	—	228	Small / older car
195/65R15	—	34	—	2.34	—	234	Very common compact
215/50R17	—	35	—	2.41	—	241	Plus-size 17-inch
205/60R16	—	34	—	2.34	—	234	Taller 16-inch
225/40R18	—	36	—	2.48	—	248	Low-profile 18-inch
225/50R17	—	35	—	2.41	—	241	Touring 17-inch
245/40R18	—	36	—	2.48	—	248	Wide touring 18-inch
205/55R16	—	34	—	2.34	—	234	Typical mid-compact OEM

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 CoolCar.

How to set the CoolCar

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

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

Martin Motors notes

No special Martin Motors exception: the CoolCar 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 Martin Motors CoolCar 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 Martin Motors sticker and this page disagree, the sticker wins.

Other Martin Motors models

MM620 CEO MM520 Bubble

Questions about this CoolCar

Front versus rear on the Martin Motors CoolCar?

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 is that in bar and kPa for the CoolCar?

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

When does TPMS warn on a Martin Motors CoolCar?

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.

Is the sidewall number correct on a Martin Motors CoolCar?

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

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