Caterham · R300 Superlight · PSI

Caterham R300 Superlight tyre PSI

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

A Caterham R300 Superlight run at sidewall-max (often 44–51 psi) is over-inflated for this passenger car. The operating PSI is 32-35/32-35. Size estimates on this page include 225/40R18, 225/50R17 and 185/65R15 — interpolated from the catalogue midpoint, not a second factory sticker.

Caterham R300 Superlight placard versus sidewall

Sidewall PSI is a carcass maximum. Recommended operating pressure for this R300 Superlight is the pillar sticker, near 34/34 psi.

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

Estimated pressure by tyre size (225/40R18 and others)

If your Caterham R300 Superlight no longer wears the OEM diameter, start at the row nearest 225/40R18 or 225/50R17 and confirm with the tyre maker’s load table.

Tyre size	Front PSI	Rear PSI	Front bar	Rear bar	Front kPa	Rear kPa	Note
225/40R18	36	36	2.48	2.48	248	248	Low-profile 18-inch
225/50R17	35	35	2.41	2.41	241	241	Touring 17-inch
185/65R15	33	33	2.28	2.28	228	228	Small / older car
195/65R15	34	34	2.34	2.34	234	234	Very common compact
215/55R16	34	35	2.34	2.41	234	241	Slightly wider 16-inch
225/45R17	35	35	2.41	2.41	241	241	Sport 17-inch
215/50R17	35	35	2.41	2.41	241	241	Plus-size 17-inch
205/60R16	34	34	2.34	2.34	234	234	Taller 16-inch

How to set the R300 Superlight

Park the Caterham R300 Superlight for at least three hours (cold tyres).
Use a calibrated gauge, not the only meter on a forecourt hose.
Set the placard for that axle — about 32-35 psi / 2.2-2.4 bar front and 32-35 psi / 2.2-2.4 bar rear on this catalogue row.
Recheck all four. A 2 psi miss on a front-wheel drive R300 Superlight is enough to feel a pull.
Refit valve caps and reset TPMS if the handbook asks for a relearn.

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	35 psi / 2.41 bar	36 psi / 2.48 bar
Motorway + luggage	36 psi / 2.48 bar	38 psi / 2.62 bar

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 tyre pressure should a Caterham R300 Superlight 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 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.

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.

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