McDougald (plaintiff) was driving on the highway behind a truck driven by Perry (defendant) when a spare tire attached underneath Perry’s truck came loose and crashed into the windshield of McDougald’s car. McDougald brought a negligence suit. The evidence at trial showed that the spare tire had been placed in a cradle beneath the truck and held in place with a chain. Instead of the chain being attached with a latch as originally designed, the chain was attached with a nut and bolt at the time of the accident. It appeared that the accident occurred when one of the chain's links came apart from the nut. The trial court instructed the jury on res ipsa loquitur, and the jury returned a verdict in favor of McDougald. The appellate court reversed. McDougald appealed.