Why Synthetic Blocks Under Tires?

In an edition of your RV Doctor Newsletter, you said to use non-absorbing, synthetic blocks under the footprint of the tires when parked asphalt. Would you explain why? Don B., (North Las Vegas, NV) 

I do tend to favor blocking under the tires, Don, to raise them up off whatever surface you store the rig on, especially if it’s stored on asphalt. Simply put, petro-chemicals can be damaging to rubber components. Using the plastic blocks keeps the tires dry and out of contact with the asphalt. I’m not a fan of wood blocking for long-term storage since wood has a tendency to absorb and hold moisture. The less moisture, the less chance of mold and mildew to develop and grow. Moisture can also attract and sustain certain critters and if I’m away from the coach, I’d rather it be high and dry. Granted, the advantage might be subtle and likely immeasurable, but old habits are just hard to break.

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