Dry rot is when the rubber in tires dry out, becoming hard and brittle. The hardened rubber becomes prone to cracks and punctures, meaning that if a tire develops dry rot beyond a certain limit it needs to be replaced immediately.
Dry rot occurs when special resins in the rubber degrade and leak out. These resins are infused into the tire material with the function of keeping the rubber moist during the lifespan of the tire. Therefore, when the resin leaks out of the tire, it loses its protection against drying out and dry rot gradually sets in.
There are a handful of specific causes of dry rotting in tires, these include:
- Excessive exposure to UV rays from sunlight.
- Constant contact with water on the surface of the tire.
- Experiencing regular, rapid fluctuations in temperature.
- Exposure to oxygen and ozone.
Crucially, tires that are stationary for long periods of time are prone to dry rotx. This is because the resins that keep moisture in a tire need regular pressure to be activated. This pressure comes from being ridden on during driving.
Since tires in storage (either on a vehicle or kept as spares) are more prone to dry rotting, extra steps need to be taken in order to protect them from this degradation. The following is a guide on how to do this.
1. Cleaning your tires before they go into storage
Given that one of the biggest contributors to tire dry rot is constant exposure to moisture on the surface of the tire, storing a vehicle with muddy tires can lead to the tires dry rotting. As the water in the mud evaporates, moisture within the tire (including some of the resin within the tire) evaporates as well, leading to dry rot.
It is therefore important to clean your tires thoroughly before you put a vehicle into long-term storage.
The best way to clean your tires is with warm water and a small amount of dishwashing detergent. Try to avoid using special tire cleaners as these often use ingredients that can further degrade a stationary tire (they are designed to be used on tires that are regularly in motion). Rinse and dry your tire thoroughly after cleaning as the residue left by cleaning liquids can damage your tire if not properly washed off.
2. Ensure that your tires are properly inflated before they go into storage
Although keeping your tires fully inflated does not slow down or prevent the dry rotting process, it does help protect the tire from cracks that can be caused if some dry rotting sets in.
Dry rot itself can, to a certain extent, be treated and affected tires can be restored to road-worthiness. Tires with cracks in the sidewall or towards the side of the tread cannot be driven on and need to be replaced. Therefore making sure that your tires are fully inflated, or even slightly overinflated (since they will lose air over time), before they go into storage should ensure that you can keep your current tires when you start driving again.
3. Keep your tires out of direct sunlight while in storage
Given that exposure to UV rays from sunlight is one of the biggest causes of dry rotting in tires, you want to keep your vehicle out of direct sunlight when in long-term storage.
For indoor vehicle storage units without any windows then this should not be a problem. However, if there is any risk of your tires getting regular exposure to direct sunlight then you should consider getting a dark covering for your vehicle. While special car covers are available, a dark blanket or tarp that is large enough to cover your vehicle will work just as well.
4. Keep your vehicle in a climate-controlled storage unit if possible
The dry rotting of tires can be sped up if tires are kept in conditions where the temperature regularly fluctuates. Similarly, environments that are excessively dry or humid can also contribute to dry rot.
Ideally, you want to be storing a vehicle in a climate-controlled storage unit. If this is not possible then ask the manager of your storage space what the typical temperatures are during the day and during the night in your storage unit. In particular, you want to avoid units that are regularly at temperatures above 77 degrees Fahrenheit or where there is regularly more than a 50-degree swing in temperature between night and day
5. Remove the tires from your vehicle (if possible)
Ideally, you do not want to store a vehicle on its tires for more than a couple of months.
This is partially because of the risk of dry rot, but also because stationary mounted tires run the risk of “flat-spotting”, that is flat spots developing where the stationary tire comes into contact with the ground below it.
The best way to store a vehicle for a long term is to remove the tires from it and have the vehicle-mounted on jack stands. Be aware that not all storage facilities will allow this, or have jack stands to provide you with, so be sure to ask for permission from the storage unit manager beforehand.
If you are going to store a vehicle for a long term without removing its tires, then try to move the vehicle once every two months if you can. This should change the part of the tire that comes into contact with the ground and should therefore reduce the risk of flat-spotting.
6. Keep spare and removed tires in bags
Given that exposure to oxygen can cause dry rotting in stationary tires, keeping such tires in airtight conditions is the best way to ensure minimal deterioration while in storage.
You can buy special tire bags, however these are expensive, often costing over $30 per tire. Instead, it’s worth going to your local hardware store and purchasing large, thick plastic bags and duct tape. While taped-up bags are not necessarily airtight, they should give your tires enough protection from excessive oxygen and water that dry rotting should not be a problem.
Tires are designed to be in regular motion, therefore keeping them in storage, either attached to your car or as spares, is never ideal. That being said with the right type of care and storage solutions, the risk of deterioration such as dry rot and flat-spotting should be minimized.
