Today's scarce automotive supply? Tires

Combine rising raw materials costs, reduced production capacity and manufacturing bottlenecks, and the result for the world of tires is this: not enough hoops to satisfy automaker demand. According to Automotive News, even before The Great Recession hit, a Bridgestone tire executive said that plant closures alone killed 71 million units of capacity in the U.S. New factories and factory expansions are on the way, but they won't run at full power until 2013.
Current production is also slowed down by having to construct low-volume tires and niche sizes, with more specialty cars and more sizes on the market. On top of that, the prices of materials like steel, carbon black and rubber that go into tires have risen an average of 52% in each of the last two years, sending tire prices "up very sharply."

Although it's predicted that "the shortage won't be resolved any time soon," from the looks of it car manufacturers are in control of the situation – as well they must be, since they can't sell cars without tires. OEMs haven't discussed what its done to the bottom line – or how much of the cost is passed on to buyers – but if you see spec sheets begin to list more tire makes as original equipment, maybe this is why.