Re: old tires

["Guy R Day" <grday@btinternet.com>]

There are many, many things that will degrade tyres.  These range from UV, 
through solvents, ozone and other gasses to swapping them round the car and 
stacking them incorrectly to store them.  Even the effects of having arc 
welding near to them will reduce the effectiveness of the tyre's structure.
There were even problems (many years ago) because a small external side door 
was left open during hot weather in a tyre manufacturing plant and internal 
metal beading didn't bond to the rubber as it should.
There are over 50 differing materials to one of those 'black and round' 
things that are the SOLE contact between the road and your motor.  You can 
get lucky and not have an old tyre undergo a blowout at speed (usually is 
because that's where the temperatures rise) but I wouldn't want to risk your 
butt on them, never mind mine.

Tyres contain - amongst other things
Rubber/elastomers
Butyl rubber
Carbon black
Silica
Textiles
Zinc oxide
Copper
Sulphur
Cadmium
Steel
Lead and lead comounds
Stearic Acid (solid form)
Organhalogen compounds   [ Don't look these up to see what they can do! 
You'll never eat (or breath in the dust from) another tyre again :-) ]

In many USA States and in the UK they are classed as hazardous waste and 
they are a little more complex than the 'black and round' attitude most of 
us take in regards to them.


Guy R Day
A-H Sprite MkIV