During 1927 Charles Van Eugen convinced the directors of Lea-Francis to allow him to design a completely new chassis assembly. Incorporating semi-elliptic springs front and rear the new chassis was longer and with a wider track than previous models. The trailing end of the springs was mounted in such a way that it slid in bronze trunnions, which were themselves able to rotate in their mounting. When well maintained this arrangement gave the new chassis a good ride quality and comparatively good road-holding for the period. The spur gear differential was gone in favour of a bevel gear version and torque reaction was now taken by the rear springs. The hand brake no longer operated on the transmission but instead through a second set of shoes in each of the rear brake drums. The radiator, while retaining the distinctive shape was taller and higher. A new plate clutch was designed which was eventually fitted to all cars on the new chassis when fitted with a Meadows 4ED engine.
This new chassis fitted with the 1.5 litre Meadows 4EC engine was designated the U Type. Fitted with a standard single port Meadows 4ED engine it was designated the P Type and with the twin-port Brooklands version of the Meadows 4ED engine the O Type. This chassis frame would also form the basis for that used on famous Hyper or S Type, the V Type and W Type. Made 3” longer the frame was also used as the basis for the T Type
While the basic specification of theP Type remained more or less the same over the years, many detail changes were made to the design. 38 of the early P Types were fitted with a cone clutch, but after that all but the last few cars were fitted with the Lea-Francis plate clutch – a reliable and effective unit that would prove quite capable of handling the power of a supercharged engine when used in the S Type. The first 500 or so cars were fitted with a scuttle mounted petrol tank feeding a Solex carburettor by gravity. On later cars the petrol tank was moved to the rear, slung between the rear dumb-irons of the chassis and petrol was now fed to the carburettor by way of an Autovac. With the petrol tank now at the rear, the spare wheel had to be relocated and, with a redesign of the front wings, was now mounted on the side of the scuttle. The majority of P Types were fitted with the standard wide-ratio gearbox, although customers could specify the close-ratio variant, as they could the Lea-Francis patent free-wheel. The latter being a unit secured to the rear of the gearbox, operated through a second gear-lever, and which, when engaged, worked with the same principle as the free-wheel on a bicycle. The last few P Types were fitted with a Borg & Beck clutch and the duo-gearbox, which had been designed for use in the Ace of Spades.
A wide range of bodies were fitted to the P type. The most common being four seaters by Avon and Cross & Ellis and two seater and dickey bodies by the same builders. Cross & Ellis fitted many of the chassis with saloon bodies with a few also being built by Vulcan. While perhaps the most advertised optional extra on this model was the aforementioned Lea-Francis patented free-wheel, customers could have a car built with all manner of variations from the standard specification. Some P types, for example, left the factory fitted with the twin carburettor 12/50 Brooklands specification engines. This made them more of less identical to an O Type and may explain why so few of the latter were built.
The P type, with the standard single-port engine, became deservedly popular, selling almost as well as the J type and surviving in far greater numbers. Approximately 1093 were built of which at least 97 have survived (with 71 in the Club), so it has become the most familiar pre-war Lea-Francis.