The Lanchester Thirty-Eight was designed by the youngest brother, George Lanchester assisted by Frederick Lanchester acting as a consultant which was a reversal of their previous roles.

By the end of 1913 Frederick Lanchester would cease to have any connection with the company at all. However as the 38 hp was a development of the preceding 28 hp which was designed by Frederick this car may be said to have more of Fred than of George in it.

The car had a 4.8 litre straight-six and was connected to a Lanchester patent compound epicyclic gearbox (with 3-speeds and reverse and a with separate high pressure lubricating system) via a multi-disc clutch.