1.   Martin lost the lap when a wheel on his car became loose.

2.   Sixteen-inch wheels became standard, second-generation air bags were added, and the car got a new rear suspension.

3.   Sixteen-inch wheels became standard, second-generation air bags were added, and the car got a new rear suspension system.

4.   The formula explains why wheels become less efficient as they wear down.

5.   With living room furniture kept sparse, he was allowed to roller skate inside until the wheels became too dirty.

6.   Now, custom wheels have become status symbols.