Tyre pressures at Pembrey Circuit

The lap, to scale. Track outline © OpenStreetMap contributors (ODbL).

How hard a circuit works each corner of the car shows up as tread temperature, and temperature is what sets pressure. GripCalc carries corner heating figures for Pembrey Circuit as a starting point: how much hotter each tyre runs over the session's base temperature, from the layout's mix of corners and load. They pre-fill the calculator when you pick the circuit, and your own pyrometer readings refine them from the first session.

ESTIMATED — class-based starting values over an 85°C session base, derived from this layout's type (direction, speed profile, load), and shared with circuits of similar character rather than measured here. Not gospel: enter your own pyrometer figures after a session and they take precedence.

Pembrey Circuit, on paper

OSM — the sections mappers have named on this venue's tarmac: Rallycross · Honda · Dibeni · Hatchets Hairpin · Cowles Straight · Woodlands · Speedway Straight · Brooklands Hairpin · Senna Esses

Lengths are measured from the OpenStreetMap geometry drawn above; the longest straight is derived from the same line and is approximate. Section names are the venue's, and can belong to any of its layouts.

What Pembrey Circuit asks of a tyre

Pembrey Circuit measures 1.11 km on the map, with 8 corners counted along that line. That is a corner every 138 m, so the tread is asked for something almost continuously: heat arrives early and keeps arriving, and pressures climb through a session faster than the morning's ambient reading suggests. It is a short lap, so those corners come round again and again within a session — heat accumulates lap on lap, and going out with pressures that were right at the start is the classic way to finish a session several psi over target. Nothing on the lap is straight for longer than about 159 m, so there is no stretch where the tread gets a real chance to cool.

DERIVED — length, corner count, hands and straight measured from the mapped lap drawn above. Corner counting is a judgement (a double apex can be read as one corner or two), so treat these as this line's reading of the circuit, not a series' official figures.

Pembrey is Welsh club racing's home: a compact former airfield circuit with a proper mix of quick sections and tight corners, and a surface with real bite. The hairpin and the complex ask for braking stability and traction; the faster sweeps keep the tread working between them.

A 992 GT3 on Cup 2 R at Pembrey Circuit

Published hot target 30.5 / 32.0 psi at 92°C tread, on a 15°C morning, with the corner figures above: cold set 21.5 / 21.5 front, 22.6 / 22.6 rear. A different car, tyre or morning moves every number, which is what the calculator is for.

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