What causes weather checking (surface deterioration or crazing) of a tire and when is it of concern?
Weather checking, often mistakenly called dry rot, occurs when the surface rubber loses it ability to stretch without breaking. This can result from aging, extended exposure to ultraviolet light, the presence of high levels of ozone, chemical or solvent deterioration, under inflation, heat damage, or a lack of frequent usage. Weather checking can also occur when the protective chemicals in the rubber are removed from the tire surface by frequent washing or the use of some protective dressings. Minor weather checking is of little concern. However excessive cracking can affect tire durability. Surface crazing that is more than 2/32 inch (1.5 mm) deep is excessive and should necessitate removal of the tire(s). Random weather checking that grows into circumferential cracks is serious. And finally deep cracking at the edge of the tread may indicate a separation and weakening of the internal structure of the tire. Tire rotation at 5000 mile intervals is recommended to monitor conditions of w
