In a message dated 12/30/2005 10:17:06 A.M. Pacific Standard Time,
bimmerdogs@comcast.net writes:
For the Golden Gate Chapter BMW CCA classification system, I suggested
(based on comments by an Ohio-based former tire engineer) using a
durometer to test the hardness/softness of the rubber of new tires.
Supposedly a member actually bought the durometer, but I haven't seen
it yet. At least that would give us numbers we could compare between
brands, but it does not address that sidewall stiffness factor.
Durometer is not reliable. Do you durometer a full tread tire or one that
is shaved? One with heat cycles or not. At what temperature? A tire can
durometer fairly high (the higher the number, the harder the rubber) at 60
degrees but change to a soft tire when heated, and another tire will not
respond
the same. Durometer has been bandied about as a measurement device in SCCA
for 20 years but no one has shown it to work.
Charlie
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