Designed in late 1925, the 1926 Lea-Francis range saw a number of modifications being made to the chassis design. The newly designated J, K, L, M and N types kept the quarter elliptic rear springs, hand-brake operating on the transmission and cone clutch of the earlier models, but with improvements such as stiffer rear cross-members and improved rear spring mounting. All models, except the G Type, now came with four wheel brakes as standard.
When fitted with the then new, higher revving Meadows 4ED engine, motor cars on this chassis were designated L or M type. The 4ED engine featured a separate aluminium crankcase and a pressure fed crankshaft mounted on three white-metalled main bearings. This with alloy connecting rods and larger ports in the cylinder head and a reasonable camshaft profile gave a more powerful and easier revving engine than the 4EB and 4EC types. In fact, while arguably a little too powerful for some of the components on the earlier Lea-Francis cars to which it was fitted, the Meadows 4ED became the engine of choice for the majority of the company’s cars from this point on.
The M Type was usually fitted with a single Solex carburettor and designated the 12/40. Not as quick as the L type, the M type was still faster than J and K types with their slower revving 4EC and 4EB engines. The M type was equipped with Hartford shock absorbers on the front only and many had Dewandre brake servos. Most were two-seater or four-seater tourers or saloons.
236 M types were built of which possibly six have survived, four owned by Club members.