tires resting on concrete

[Rockhead]

Originally Posted by jgreth

Amphibious vehicle - Wikipedia, the free encyclopedia

BOAT loads of them!! HARRRRRRRRRRRRR









Sporty version. They go 100 mph on land and 30 mph in the water and go on sale in the US in 2009 for $85,000.

Two foot wake and that bad boys swamped. 30mph though thats rather impressive.

[Mydlyfkryzis]

Originally Posted by busa-boy33

I see this alot on boat tires and mc's if they are not moved around but they are just cracked, usually some loss of air, and looks as if you take them down the road they will fall apart.

Dry rot is caused by ultraviolet light (Sunlight). That's why people with campers cover the tires when parked. Also, smog and oxygen work their own brand of magic on the rubber. Over time, the rubber hardens. That's why old motorcycle tires have less traction, the rubber is harder then when new.

Cured concrete doesn't effect modern batteries or tires. O2, age and ultraviolet light play havoc with tires and us...

[Easy Rider]

Originally Posted by busa-boy33

I see this alot on boat tires and mc's if they are not moved around but they are just cracked, usually some loss of air, and looks as if you take them down the road they will fall apart.

This is caused by one (or a combination) of the following:
Exposure to direct sunlight.
Prolonged exposure to (very) high heat ( > 100F)
Excessive flex because of low inflation.
Age.

It probably isn't "real" dry rot, however, since modern rubber compounds have just about eliminated that condition. A tire that has real dry rot would fall or fly apart with very little coaxing.