Getting ready to jump in your car and finding a tire with little air at an inopportune time is frustrating. Taking it to the auto repair shop and having them search for a puncture leak and not finding it is even more frustrating, especially if they’ve already tested the rim for leaks and found none.
The worst tire leak occurs at the slowest rate—slower than any consumer detection devices can capture. It’s the marginal leak that occurs from the cracked wall of the tire that faces the undercarriage of the car. Seldom seen, the hints are obvious to the specialist, but incomprehensible to the driver. The bad news is that the cracked sidewall is ready to turn into a blowout at any moment.
This type of cracking is known as dry rot. The most common cause is improper storage or infrequent use. Dry rot occurs when the oils in the rubber begin to evaporate. The chemical bonds breakdown, are lifted off the tire from a nearby heat source and leave a dry tire behind. An additional cause is low inflation of the tire.
Cars that sit in the sun or in balmy climates deteriorate even faster. The only way to store a car for long periods of time without speeding the dry rot is to store it in a climate-controlled garage, keep the tires inflated at manufacturer’s specs, park the tires over wood boards, and check the tire pressure monthly.
There are some who suggest that dry rot can be fixed if caught early enough, but the only guaranteed safe solution is to replace the tires. While some dry rot tires might last a few months with local driving, it is extremely hazardous on the highway. Once the cracks reach the cords of the tire, the heat generated from a long drive is sufficient to cause the rubber to expand and the tires to break apart while driving—a deadly consequence.