The sign accompanying the SR-71 tire. It reads
SR-71 Aircraft Tires
Why are SR-71 tires silver? SR-71 tires, like the one displayed here, were
infused with powered aluminum. The addition of aluminum to the rubber gave a
much higher flash point to the tire, helping it withstand the high heat caused
by friction with the ground upon landing at extreme speeds. The tires were
also filled with nitrogen. By inflating the tires with nitrogen, instead of
air, a fire would be less likely to start due to the absence of oxygen. Each
tire cost $2,300 and would last for approximately 15 full-stop landings.
Heat was not just a problem on the ground. The SR-71 needed to deflect a large
amount of heat as it flew at an average speed of Mach 3, or roughly 2000 mph!
At this extreme speed, the metal skin of the SR-71 would heat up to 400 degrees
Over 90 percent of the aircraft's frame was made of titanium to withstand the
intense heat. In addition, the SR-71 was painted with a highly sophisticated
and specially formulated black paint to radiate excess heat. The special paint
also provided protection against detection by disturbing incoming radar energy,
rendering the aircraft less detectable by enemy forces. An interesting side
effect was the resulting changing of the speeding aircraft to a lovely blue.