Dunlop SP8000 tread separation at Pahrump

[Darringer, Chris]

Since we are on the subject of tires again, I thought I would relay my
experience with Dunlop SP8000s this weekend at the Quattro Club track event
at Pahrump...

I purchased 205/50/ZR15 SP8000s for my '90 80q about 8,000 miles ago, and
they exceeded my high expectations during previous track events.  Dry and
wet weather cornering were excellent.  This weekend at Pahrump, however, as
I inspected my car after the second session, I noticed that the vast
majority of the outer tread band on the front tires had shreaded off.  In
several places the nylon was showing!  

What happened?  

I noticed some sidewall wear earlier, so I made a conscious effort to back
off and prevent excessive understeer in my driving, but still... Cold tire
pressure was about 40psi.  The rest of the front tires were in excellent
condition, as were the rear tires.  Members suggested that suspension
bushings might be going bad, but a quick suspension inspection later in the
day revealed no obvious problems.

I limped the car to Vegas on Sunday morning, and managed to pick up some
205/55/ZR15 Goodyear Eagle F1s.  I drove another 60 miles on the track that
day with the new tires and no new problems.

In spite of my tire problem, I enjoyed myself enormously.  The Pahrump event
was extrememly well organized by many hard working volunteers, and the
talented pool of instructors gave me plenty of valuable feedback. 

P.S.  Later that day I caught a ride with Rupert, the owner of the track, in
a Camaro SS.  If a squealing tire is a happy tire, then the tires on that
Camaro could not have been happier.  I am not exaggerating when I tell you
that every apex cone on that track passed parallel to the front bumper of
that car.  Aside from having some fun with a Camaro, the man proved he is a
talented racer as well by setting some unbeatable lap times on the track
with his Corvette.  

Chris
'90 80q