Dumping in front of the tire can cause serious deterioration of your wheels. all of the nasty stuff in the exhaust will cover that wheel and corrode the surface badly. The "NEW 1997" Fords dumped the exhaust in front of the right rear (probably saved them $5 per truck in pipe and bends). By '98 they had a Special Service Program to replace the pipes to dump behind the wheel, and they replaced A LOT of wheels that were etched...

If you wash religiously, you can prevent/delay it.