If you truely want to know your tire hardness, you need to use the JOES Precision Digital Durometer. The JOES Digital Durometer automatically records the highest number and has an average mode if you want to check several spots on the tire. Do it right with a JOES Digital Durometer. Included in the kit is a JOES Digital Tread Depth Gauge which accurately measures tire wear for optimal camber adjustments. Auto shut off feature and includes a carrying case.