The tire store is located on the 4800 block of El Cajon Boulevard.
The flames were spotted around 1:30 a.m. Monday. The first firefighters on the scene saw toxic smoke coming from the burning rubber.
Crews were able to stop the fire from spreading too far inside the building. If the inside of the store had gone up in flames, fire officials said, the store and its surrounding buildings would have burned.
The cause of the fire is under investigation.