Caterham · R300 Superlight · Rear

Caterham R300 Superlight 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

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 Caterham R300 Superlight is 32-35 psi / 2.2-2.4 bar. Size estimates on this page include 225/45R17, 185/65R15 and 215/50R17 — interpolated from the catalogue midpoint, not a second factory sticker.

Caterham R300 Superlight placard versus sidewall

The tyre-information placard on a Caterham R300 Superlight 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)

225/45R17 is the first planning size here. 215/50R17 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
225/45R17	—	35	—	2.41	—	241	Sport 17-inch
185/65R15	—	33	—	2.28	—	228	Small / older car
215/50R17	—	35	—	2.41	—	241	Plus-size 17-inch
195/65R15	—	34	—	2.34	—	234	Very common compact
225/50R17	—	35	—	2.41	—	241	Touring 17-inch
225/40R18	—	36	—	2.48	—	248	Low-profile 18-inch
205/60R16	—	34	—	2.34	—	234	Taller 16-inch
215/55R16	—	35	—	2.41	—	241	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	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 R300 Superlight.

How to set the R300 Superlight

Measure before the school run, not after the M25.
Write LF / RF / RR / RL. Do not keep R300 Superlight 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 Caterham R300 Superlight 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 R300 Superlight.

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

Caterham notes

No special Caterham exception: the R300 Superlight 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 Caterham R300 Superlight 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 Caterham sticker and this page disagree, the sticker wins.

Other Caterham models

Seven 485 21 Superlight Seven SV Classic S7 R 400 Cosworth CSR 200 Seven 620

Questions about this R300 Superlight

Front versus rear on the Caterham R300 Superlight?

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 PSI if I plus-size toward 215/50R17?

Keep load index at or above OEM. Low-profile sizes usually stay at or slightly above the placard. Use 225/45R17, 185/65R15 and 215/50R17 as a planning band.

Is the sidewall number correct on a Caterham R300 Superlight?

No. Sidewall PSI is a maximum. The R300 Superlight placard is the operating target, near 32-35/32-35 psi.

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 is that in bar and kPa for the R300 Superlight?

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