Dunlop SP8000 tread separation at Pahrump

[Larry C Leung]

Partially the tire's fault (not stiff enough, in spite of appropriate
pressure) partially the driver's fault (understeer is possibly caused by
too high a turn entrance speed, understeer out is the tire/car/driver
pushing too hard for the car), partially the alignment settings (too
little negative camber, not enough anti-roll). Believe it or not,
contrary to popular wisdom, with stock suspended VAG's a big front bar
helps a lot by limiting camber change. 

LL - NY

On Tue, 24 Apr 2001 12:57:58 -0700 "Darringer, Chris"
<Chris.Darringer at schwab.com> writes:
>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
>
>
>