Caterham · R300 Superlight · Overview

Caterham R300 Superlight: 2.2-2.4 bar / 32-35 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

On a Caterham R300 Superlight the useful pair is 34 psi (2.31 bar) up front and 34 psi (2.31 bar) at the back, mid-range. TPMS typically warns near 25 psi (about 25% below target). That is already a soft tyre, not a fill target.

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.

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

1 bar ≈ 14.5 psi; 1 psi ≈ 6.89 kPa. Mid-points on the R300 Superlight: 34 psi = 2.31 bar = 231 kPa.

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

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.

Temperature and a cold gauge

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.

Estimated pressure by tyre size (225/50R17 and others)

If your Caterham R300 Superlight no longer wears the OEM diameter, start at the row nearest 225/50R17 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
225/50R17	35	35	2.41	2.41	241	241	Touring 17-inch
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
185/65R15	33	33	2.28	2.28	228	228	Small / older car
215/50R17	35	35	2.41	2.41	241	241	Plus-size 17-inch
245/40R18	36	36	2.48	2.48	248	248	Wide touring 18-inch
205/60R16	34	34	2.34	2.34	234	234	Taller 16-inch
225/45R17	35	35	2.41	2.41	241	241	Sport 17-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	37 psi / 2.55 bar

A cheap gauge and a monthly habit will do more for this R300 Superlight than nitrogen upsells.

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.

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.

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.

When does TPMS warn on a Caterham R300 Superlight?

Direct TPMS typically flags about 25% below placard — near 25 psi on this row. Fill to the sticker, not to the lamp.

What PSI if I plus-size toward 215/55R16?

Keep load index at or above OEM. Low-profile sizes usually stay at or slightly above the placard. Use 225/50R17, 195/65R15 and 215/55R16 as a planning band.

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