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I have learned an expensive lesson...yes a squealing tire is a happy tire as my instructors told me at the Skip Barber racing school, but to a limit. Has anyone else blown $700 of tires (fronts) in 20 laps?
How new were the tires? And what PSI did you have them set at? Scary!
-Luccia
4,000 miles on them. I set the fronts to 35 psi cold. They come up to 42 psi as maximum pressure on the track. I set the rear at 38 cold and they come up to 46.
I was in the middle of turn 11 when I started sliding (severe understeer) and my rears started making a noise like they had both gone flat all of a sudden. I immediately pitted and after a quick inspection of all tires I realized that the fronts were indeed falling apart (chunking) and the rears were picking up whatever the fronts were shedding.
Have you contacted Pirelli? Those aren't all season tires from Walmart. Seems to me that they may be so embarrassed by their products' performance that they'll replace them
4,000 miles on them. I set the fronts to 35 psi cold. They come up to 42 psi as maximum pressure on the track. I set the rear at 38 cold and they come up to 46.
I was in the middle of turn 11 when I started sliding (severe understeer) and my rears started making a noise like they had both gone flat all of a sudden. I immediately pitted and after a quick inspection of all tires I realized that the fronts were indeed falling apart (chunking) and the rears were picking up whatever the fronts were shedding.
4,000 and they did that?! Yikes! Do you know what appropriate tire pressures are for those tires on that track? 42 PSI seems high to me, but I am no expert pertaining to this track and tire set up. I run Nittos for the track.
Edit: I'd second the calling Pirelli as well, but they may ask about the tire pressure level.
Have you contacted Pirelli? Those aren't all season tires from Walmart. Seems to me that they may be so embarrassed by their products' performance that they'll replace them
I am considering...I had the tires replaced by my Porsche dealer (only one in town with these freaking tires in stock!!!) and the mechanic who replaced them said: " That is what happens when they get overheated".
I would think that if I push them too hard, they would just wear a lot faster, versus just blowing chunks of rubber and totally fall apart.
4,000 miles on them. I set the fronts to 35 psi cold. They come up to 42 psi as maximum pressure on the track. I set the rear at 38 cold and they come up to 46. I was in the middle of turn 11 when I started sliding (severe understeer) and my rears started making a noise like they had both gone flat all of a sudden. I immediately pitted and after a quick inspection of all tires I realized that the fronts were indeed falling apart (chunking) and the rears were picking up whatever the fronts were shedding.
Not sure about the track, but for the street those psi's are very very high.
<laughing>....contact Pirelli !! Right-oh. It's not always someone else's fault. SOMETIMES you need to get the right tool for the job and if you're going to do track days on street tires and drive the car hard, this is what happens. Doesn't matter what the brand or what your tire pressures are. You put a lot of heat into a tire that is not designed for that and this is exactly what happens. It's going to chunk first, then separate. Shumi, you are probably driving the car pretty hard, its perfectly normal for that to occur if you are. What you really should so is buy a spare set of track wheels - they don't need to be pretty, just straight - and mount up some R Compounds that will fit (Better to go with 19" than 20" for the track wheels) and get them from Tire Rack. They have a heat-cycle and shaving service and the track tires will arrive ready to go. Shaving a brand new tire may should silly, but it prevents overheating and chunking, and you do have to properly heat cycle a new set of R-Comps before you start running them. Once you have R's on the track, you'll never drive a street tire on a circuit again.
You must have been locking the fronts on braking.
Hard to believe that was from just cornering, as cornering wears the shoulders.
How did your rear tires look?
For me, the rears wear far more than the fronts.
Do you have PDCC and or SPASM?
BTW - It is possible to trash any tire in a dozen laps (even a track tire) if you overdrive the car.
I don't run certian tracks [Willow Springs] because some tracks eat tires for lunch.
<laughing>....contact Pirelli !! Right-oh. It's not always someone else's fault. SOMETIMES you need to get the right tool for the job and if you're going to do track days on street tires and drive the car hard, this is what happens. Doesn't matter what the brand or what your tire pressures are. You put a lot of heat into a tire that is not designed for that and this is exactly what happens. It's going to chunk first, then separate. Shumi, you are probably driving the car pretty hard, its perfectly normal for that to occur if you are. What you really should so is buy a spare set of track wheels - they don't need to be pretty, just straight - and mount up some R Compounds that will fit (Better to go with 19" than 20" for the track wheels) and get them from Tire Rack. They have a heat-cycle and shaving service and the track tires will arrive ready to go. Shaving a brand new tire may should silly, but it prevents overheating and chunking, and you do have to properly heat cycle a new set of R-Comps before you start running them. Once you have R's on the track, you'll never drive a street tire on a circuit again.
Excellent point drcollie....but fairly expensive. We are talking about spending another $5000. The R Compounds wear much faster than extreme performance summer tires, right? Here is an argument for not going the R compound route so quickly: http://www.porschenet.com/activities...ompound-tires/
Regarding my set up on that day:
Front: 35 cold
Rears: 38 cold
I had a passenger, track ambient temp at time of failure 80F.
04-23-2015, 04:54 PM
