Yep another question about TIRES?

[NGC 613]

Maybe somebody on here knows why it is a campers tires dry rot fast when it sits? When the unit is on the road moving they don't seem to dry rot.
What am I missing on this? Even when folks use tire covers they tend to dry out. I'd like to know what it is that makes this happen to them.

 

[AbdRahim]

rolling distributes the lubricant in the rubber. Sitting, the outside dries out and is not replenished,