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The sign accompanying the A-12 tire. It reads

"Tire Problems?"

The main landing gear tires on Blackbirds have some very difficult problems to overcome. They are subjected to very high heat for several hours at a time. The temperature inside the wheel wells exceeds 800° Farhenheit. The main gear has to support the weight of the aircraft on landing and take off speeds above 180 knots.

The Blackbird has the heaviest footprint of any Air Force aircraft ever made. Each tire on the main gear has a contact patch of only about 13 square inches each.

This display shows the tire after only 3 landings. Notice the small thread width and cord layers showing. These tires are designed with about 15-20 landings and take offs in mind. They are inflated with nitrogen to 325 PSI. The tires appear to be silver in color because they are made with aluminum powder to reflect heat.

B.F. Goodrich 22 ply
239 Knot 27.5 x 7.5-16