As a classic car owner, you understand the importance of replacing your tires when they become too worn out to provide adequate traction and safety. But your tires can become compromised even before they begin to bald. One of the most common reasons car tires may wear out prematurely is the development of tire dry rot. Left unchecked tire dry rot will worsen until the tire begins to leak, or in some cases, blows out.
Tire Dry Rot, aka Sidewall Weathering, is visible cracking in a tire’s tread or sidewall caused when a tire’s rubber compounds break down. This visible cracking could be caused by a variety of factors, including but not limited to too much exposure to sunlight, low tire inflation, or simply not using the tires for extended periods of time.
What Causes Tires to Dry Rot?
The sidewall weathering that is visually evident on the tire occurs when the rubber compounds used to make the tire begin to break down.
As with most products, there is natural degradation over time and exposure to adverse environmental conditions with the rubber compounds that make up a tire. Being exposed to high ozone concentrations in the atmosphere, climate changes, outside elements and misuse, these materials can begin wearing down faster, which may lead to cracking – a condition some may call “dry rotting.” Causes that lead to tires showing signs of early sidewall weathering can be attributed to five main areas:
- Excessive exposure to ultraviolet (UV) rays from sunlight
- Low inflation pressure in the tires
- Storing tires at extremely high temperatures
- Not using the tires due to lengthy storage of a vehicle or the tires themselves
- Storing tires near electric motors, battery chargers, generators, welding equipment, or other ozone-generating sources
- Abrasive or corrosive chemicals, such as pool treatment chemicals, motor oil, and industrial cleaning solutions
- Extremely low or cold temperatures
What Does Tire Dry Rot Look Like?
Closely inspected, properties of sidewall weathering will be easily noticeable and may take the following forms. After looking at your tires, if one of the following traits of sidewall weathering is evident in your vehicle’s tires, it is recommended to contact an authorized service center or dealer to have your tires inspected to gauge the severity of the issue.
Breakable Appearance or Brittleness
The tire will appear harder than normal with the surface being brittle touching the affected areas could cause pieces of the rubber to flake off. Dry rot dries out your tires. As essential oils leech out of your tires, you may notice that they appear and feel more brittle. You may even observe small pieces of rubber breaking away or flaking off from the tire.
Cracking in the Tire’s Sidewall
Cracks on the sidewall of the tire will be noticeable and could extend to larger areas. Even in minor cases of tire dry rot, you may notice cracks on the sidewall of your tire. These cracks may appear in an isolated area or extend around large portions of your hubcap.
Cracking in the Tire’s Tread Pattern
In the case of more advanced sidewall weathering, cracks on the tire’s tread may begin to appear. Advanced dry rot can cause small cracks on the outside edges of your tire tread. These cracks can affect your car’s handling, even if your tread still has adequate depth overall.
Discoloration
The color may begin to fade and may appear to be more of a gray tone.
How to Help Prevent Tire Dry Rot?
Once deterioration becomes noticeable on tires, the best course of action is to replace the tires before additional damage can be done. Follow proper tire care and maintenance to help prolong the life of your tires from premature cracking.
- Regular Inspections:
Inspect both the sidewalls and tread of your tires monthly to monitor the overall condition, specifically looking for any cracks, discoloration, bulges, wear, or additional unnatural blemish. - Park Out of The Sunlight for Extended Periods of Time:
Too much exposure to UV rays from sunlight, especially in consistently warmer climates, is a leading cause of premature sidewall weathering. It is recommended to park in more shaded areas if your vehicle is exposed to excessive heat and sunlight. If you plan to park a vintage car or vehicle outside while storing, covering the vehicle and tires will help stave off UV rays. - Cleaning and Protecting:
The simple method is to clean the surface monthly with a washcloth using water and a mild dish soap. A water-based cleaner or solution such as this won’t harm your tires by adding any additional chemicals that could potentially impact the tire’s compounds and materials. After washing the tires with soap, give the tires a simple rinse with water. - Avoid Harmful Products and Chemicals:
If you are planning to use other tire protectants or cleaning products, read the product labels and be aware of what other chemicals are going on your tire. Stay away from using any cleaning products that are petroleum-based, as the products may degrade the rubber’s weathering agents that may lead to premature cracking. - Proper Tire Inflation:
One of the leading causes of tire failure is driving with underinflated tires. When tires are underinflated, there is increased wear on the tire tread, which generates excessive heat, and can result in severe cracking, component separation or a tire failure.
Tires should be inflated at the proper levels recommended by your vehicle’s manufacturer and tire inflation pressure should be checked monthly. If cracking or sidewall weathering is evident in your tires, keeping the tires properly inflated may be more difficult not be possible as air loss may occur through the affected areas. Maintaining proper inflation pressure is the single most important thing you can do to promote tire durability and maximize tire life. - Overloading:
Tires are specifically made to fit the vehicle and each tire has a recommended load capacity, which is the actual weight of the vehicle plus additional weight carried by that vehicle. Adding weight over that load capacity is considered “overloading”, and it will place too much stress on the tires. This additional weight to your tires may cause severe cracking or a potential tire failure. To learn more about your tire and vehicle load limits, consult your owner’s manual. - Extended Parking Care:
If a vehicle is planned to be stationary for an extended period, such as a vintage car, a trailer or recreational vehicle, it is recommended to follow the steps below:
- If possible, store the vehicle in a manner that removes as much weight from the tires as possible (such as on jack stands).
- Store the vehicle out of direct sunlight.
- Cover the vehicle and tires to protect from any unnecessary UV rays.
- If the weight cannot be removed from the tires, move the vehicle at least every three months to shift the weight on the tires.
- Store the vehicle and tires in a clean and dry area away from any chemicals or large temperature shifts.
- Tire Storage Care:
If long-term storage of winter or summer tires is planned, it is recommended to follow proper guidelines. The ideal method to store tires would be to keep them mounted on their wheels and store them on hooks through the rims themselves off the ground.
Finally
Classic cars or trucks are not driven as consistently as your daily driver, and often parked for long periods and in various locations which can seriously impact the condition of your tires.
Just as you invest in your vehicle, you must invest in your tires with the same regular inspections and maintenance. To help ward off the possibility of sidewall weathering in your tires, follow the suggestions above for proper care and maintenance. If cracks or noticeable sidewall weathering signs begin appearing drive slowly and carefully and make an appointment for tire replacement.
