How to prevent dry rot on trailer tires that will sit for months?

Park it on some 4 by 4 if you are not parked on pavement, If you have a old tarp that you can roll out across the bed and down to the ground to cover the tires with it, so that the sun won't be shining on tires, that will make them last much longer and not get dry rot?

 

That - or some plywood covers.

UV kills rubber.

 

Most tires are 99.9% synthetic rubber.

The added chemical 'rubber preservatives' in the tire work better when the tire is flexed on a regular basis so take it for a ride whenever you get the chance.

Up on blocks and covered to protect from UV all help but the rubber rolling and flexing as you drive makes the preservatives work.

 

Most RV stores carry tire covers that will fit
Elements Tire Covers, 40" - 42" (Pair)

 

Yup tire covers are about the best bet. Also a bit of 5w-30 on a sponge applied to the sidewalls inside and out every couple months helps considerably slow the process. It keeps the moisture off and helps trap the waxes and oils inside the sidewalls. Dont get them on the treds though.

 

Tire covers are good, yes. Simply making sure the tires stay inflated is, in my opinion, the number one way to prevent dry rot. On any camper, trailer, etc I've ever owned flat tires dry rot, while tires with correct pressure would take years (decade) to dry rot covered or not.

 

If not on concrete then park on plywood or rubber mudflaps or conveyor belt scraps. The asphalt or dirt/caliche will suck the oils out of the treads. South Tejas heat can cause the asphalt to puddle and stick to the tread contact patch over time. Tread separation's can occur in the localized area due to the rubber being dried out. Cover tires with heavy tarps, rv/bus covers or propped up sheets of plywood to keep the direct sunlight off of them. Same with any exposed hoses or wires along the deck.
Also if parked next to an electrical source like a pump, motor, or even an appliance like a vending machine that runs full time you need to put a plywood or something non conductive buffer between it and the tires. The constant ozone being produced by the electric source will eat away at the rubber over time.
“Green X” Michelins don’t like to sit any amount of time without cracking in the heat so good luck if you run them. Lol!

 

I like this product to clean tires.
Bleche-Wite Tire Cleaner - Black Magic

Straight simple green works too but not as well as the above.

Takes all the dirt and road grime out of the rubber and makes them black again. Follow up with a silcone based rubber protectant. Some people may knock Armour-All but it’s better than nothing IMO. Don’t care much for the tire wet products. Just makes the dirt stick again.

I see they have a UV protectant. Never tried it tho

 

If you jack up the trailer and get the tires off the ground, that will stop them from going square, tarps, plywood, tire covers for the dry rot.