In the October 23, 2000 edition (pg. 11)  of the
International Herald Tribune (IHT), there is an article
regarding the quality of tires put on new cars versus the
quality of aftermarket tires.  The article says in part:

"The replacement business is where tiremakers make their
money.  While replacement tires may look the same as the
originals, they are made in ways that hold down
manufacturing costs to make them more profitable than
original equipment tires.  So the companies' goal is to get
just enough new car business to steer customers to their
tires in the replacement market. .... because 2/3 of new car
buyers buyers replace original tires with the same brand,
according to Tire Business, a trade publication."  ....
"Original-Equipment tires may be overengineered .... because
the auto makers have elaborate specifications for fuel
efficiency, noise and handling.""

These are general statements, but the article implies that
it is general business practice. (Firestone, Goodyear, &
Michelin, the big 3).

Just thought I'd share this with you all.  Malcolm