As a car approaches collector status or just an older model where it is not driven all that often a certain amount of neglect begins to accumulate. Neglect you would not tolerate on something you drive everyday. Such as ignoring tires.
They are round and black and hold up the corners. And if I don't drive the thing they don't wear! That is the plus side.
However the minus side is that they dry rot.
I have totally lost track of the number of tires I have bought in the last 15 years. One I have at least two drivers that use tires. And 5 show cars 4 of them that sit out side in the weather that do not use tires. But the heat and the sun gets after them and here in the SW the sun and the associated UV will tear up the rubber and plastic and on a Saturn a good part of them past the tires are rubber and plastic.
I have yet to wear out tires on my Saturn. But I have purchased about 6 of them since I bought the car and it needs 2 now. Why, dry rot, the plies shift, it throws the rubber off the tire tearing up fenders.
This morning I went to a car show with one of my other cars. I have replaced the front tires twice and put a new pair on Thursday. The rear actually have been pretty good. I still had one tire I bought about 10 years ago on it and one that I bought about 8 years ago.
About halfway to the show a vibration started and while it was dawning on me a chunk of sidewall pealed off and bounced off the fender and flapped on the pavement making weird boinking noises. All of the time I am frantically trying to get slowed down. Sure nuff, a chunk of rubber was gone and the cords were showing themselves. It still held air, I nursed it home stopping at the dealer to order another tire and missed the show. All because I ignored the fact the tire was dry rotted and it was stupid to drive on it.
But not me!
I do stupid gud!
And I got lucky, all this one cost me was money.

 

Hey Unc, I've never had a car that I don't drive, but I was just wondering about something. Since you have cars like that, would storing them on jack stands in order to keep the tires from making contact with the ground or concrete or wherever you store them keep them from dry rotting? I don't know, I was just wondering, because I've got that problem with my utility trailer. I'm going to have to replace the tires on it because of dry rot and was thinking about putting blocks under it after I do, just to keep the tires off the ground. Do you think that would help or is just a waste of time?

 

Maybe not a bad idea ...

Neighbor kid just left for an extended period over in "The Sandbox". Before he left, he put his truck up on jackstands, and pulled all the wheels. It now sits at the edge of the driveway, awaiting his return.

Goodspeed, young man, return safe and sound ...........

 

Hey Ruby, yuh! however the dry rot is not so much the fact that I do have a situation where I have (to be honest) too many cars thus some sit more than others, it is more the fact that those that are not garaged sit or are parked outdoors. In my case everything on concrete.
The damage is more a function of age and time left in the sun. Even the car I drive regularly enough to wear out the rubber, is dry rotted.
We have had about (I think) 117 days this year of triple digit temperatures. Think about that one for a moment, about a 3rd of the year is over 100 degrees which means the sun is out and it is hot. That equates to rotting rubber items from UV conditions and does not even address the days where it is 90+ degrees like today where at the moment it is 67 but the high is predicted to be 91. As this is also the land of the retired elderly some with enough money to have deep pocket RV and Motor home/camping trailers it is not uncommon to see them stored with something to protect the tires. Harbor freight sells canvas slippers to cover tires with at one end of the scale and at the other end a round piece of wood or any shape piece of plywood leaning up against the tire to keep the sun off of it will extend the life of the tire.
The next step is to get tires out of the outside and into a garage or something and I have two sets of tires stashed in my garage just to get them out of the sun and the weight off of them. They are expensive and came of my Chrysler and my car I am building and are deep pocket Mustang wheels and tires. I think P235-35-19's. The next step would be to get the weight of the car or trailer off of them. As they sit they will slowly leak air and deform as they try to go flat with weight off of them they will be less prone to cracking and such. They still if outside are in the elements. But on an axle supported so they don't carry a load and with a cover I don't think you can protect better than that short of using them as a coffee table in the house.
While touching the ground can cause other problems and they are visible over time it would be the least of the problems I would think as something to expect damage from. Dirt and grass and such probably can be a problem to rubber but sun and the UV and the heat are the biggies.
And frankly other than rain of which we don't have much of with a yearly estimate of 9 inches and I don't think we have had half that for 10 years and you can get that much in an afternoon shower. You live in a really nice area, it will rain a lot and you actually have all four seasons. Off the ground and covered would be a big improvement. The cover being the biggest.
I would think

 

Well, I've got to get a new set of tires on my Grand Caravan before the winter sets in, so I think I'll just pull the two best ones from it and put them on my trailer. Fortunately, it's also got 15" tires. I'm going to get some new jack stands and will put my old one under the trailer axle for the winter and see what happens. Nothing ventured, nothing gained, right?

 

U-betcha, something some times is better than nothing. I have 2 sets of 4 wrapped in harbor freight silver tarps sitting on 2x4's to keep them off the ground. Heck the sun tears those up too. I have to replace the tarps twice a year!!!!
Oh Well