Originally Posted by jcanavera
I use the orange blocks also for leveling. The important thing when putting something under a tire is to make sure the entire tread or footprint of the tire is supported. It is possible to damage a tire by allowing part of a tire to remain unsupported. I went to a RV tire seminar years ago and this was brought up as an issue that could damage the belts.
Tires should be off the ground during storage:
Store the vehicle such that all weight is removed from the tires.
Cooper Tire & Rubber Company - Storing Tires
Ideally, a vehicle in storage should be placed on blocks to remove all weight from the tires.
Tire Storage - Goodyear RV
Don't store a vehicle with weight on its tires for extended periods of time. Long-term inactivity is more harmful to tires than weekly drives that flex the tires and help maintain oil dispersion within the rubber compounds.
If tires are on vehicle, store on blocks to remove load from the tires. Maintain placard inflation pressure.
Tire Storage | Michelin Tires
Remove the vehicle's weight from the tires (put vehicle on jack stands)
Bridgestone Commercial Truck Tires