Mikey
As you'll see, consistent advice saying the handbook figures are wrong. They are! I've no idea why Morgan ever said so low a figure but most people have tried them, given up in disgust and experimented around and found their own figures which as you see, are remarkably similar.
18 psi is even lower than was recommended for later two and three speeders of the 30s. (19 front, 25 rear if you're interested).
