Mark Hickey wrote:


Consider that a pneumatic tire supports the weight by the air pressure
that's in it - and that the contact patch of the tire is approximately
the weight on the tire in pounds divided by the pressure in psi. That
means on the hypothetical plane above (2,250 pounds, 15psi), the
contact patch (total) for the three tires would be around 150 square
inches. That's 50 square inches per tire, which on a 5.00 tire is
otherwise known as "a flat".

Mark Hickey

Agreed. More accurately, however, for this airplane there would be
about 1000 lb on each main at gross weight which, as you note, would
result in very flat 5.00-5 tires at 15 psi. The 45 psi recommendation
is correct.

- anon