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Anyone have this "shredding" problem with PZero Corsa tires?

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Old 11-07-2004 | 05:00 PM
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Default Anyone have this "shredding" problem with PZero Corsa tires?

Hi Guys,

I have the 235/315 setup on my GT2 track wheels and after only a few track days (D.Ed, not racing, not that it matters), the shoulders are SHREDDING apart!

I monitor tire temps and pressures and hover around 40psi hot, so roll-over shouldn't be an issue.

I've run Toyo RA1's, Victoracer's, BFG R1's (long time ago), Comp T/As, etc, and have never seen this happen to any tire. Usually, they just wear and look like a roughly scuffed even surface, but not shredded like this.

I'm wary of driving on them, and had someone at Discount Tire look at them I (on advisement of a Pirelli Cust Svc person I spoke with on the phone). The Discount Tire guy said he bets they will avoid helping me, saying I abused the tire by tracking it, but that doesn't sit well. They intro'd this tire as a trackday tire that also enhances street performance.

Anyone also experience this problem? Any idea how I can get help with this and maybe get a replacement set or partial credit so I can get back on track? I don't expect track tires to last forever by any means, I just expect them to hold up through their life, not to come apart prematurely and pose a hazard.

I'll try to attach a pic so you can see what I'm referring to.

Thanks for your help!
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Old 11-07-2004 | 06:15 PM
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You need to get Pirelli on the phone. Their engineers will want to see that pic. Do you have one of the tire standing up from a little further out. If you need the number of someone to contact at Pirelli I can find it for you.

As to Discount, well gee, I wonder, did you take your track tires to the track? Fing moron.
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Old 11-07-2004 | 06:24 PM
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Thanks, yeah, I'd love to get a number of someone who can make a difference at Pirelli. I just called the number off the web site and got a gal who referred me to Discount Tire, and it probably could be approached much better another way. I just don't know who to call.

Thanks for any help you can provide in this regard.
Old 11-07-2004 | 07:36 PM
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I'm not sure if I agree with you guys. This looks like a typical case of not enough negative camber and hard shoulder wear on track surface. Also, I am not sure if 40 psi hot is ideal for these tires. Usually, R-compounds like to run less than that. What you really need is a good tire pyrometer to see if your inner, mid and outer temperatures are close.
Old 11-07-2004 | 07:45 PM
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Agree with Viken, get a good pyrometer and check those temps, also on Corsas I start with 26pnds cold,never have an issue with them,cheers,Sonny.
Old 11-07-2004 | 08:26 PM
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By the looks of the tire from the pictures, would you say they are unsafe to drive on? That's what I'm assuming, but not sure since I haven't seen this before.

Thanks for the feedback. The camber issue may be a strong factor for sure. As for R-compound tires liking less than 40psi hot, I guess it depends on the tire. The Toyo RA1 seems to thrive in that area, but not makes are alike. I use a pyrometer, but perhaps it wasn't used in this instance during these few trackdays on these tires. I guess I'm just sort of surprised to see the tire start to separate like this. I've been in cars that didn't have an optimum racing alignment, and the tires just didn't do this. And I'm talking about several different brands of tire. Anyway, thanks for the feedback, I just thought this was atypical somehow.

The pic was of a front tire. On the rears, they're starting to lose chunks about 2 inches in from the shoulder. Looks like they weren't dissipating heat evenly enough either. That's kinda my point. In the case that alignment isn't optimal (and let's say in this case it wasn't on this street/track car), and you're on a wider tire that dissipates heat better and reaches overheating later versus a narrower tire, given the same alignment, shouldn't a tire of this caliber hold up under enthusiast trackday lap sessions that are rarely more than 20min at a time? I may be really unbalanced looking at this, since my most recent tires to compare are the Toyo's and darn if they don't take a beating no matter your alignment. They held up with conservative camber and aggressive camber situations alike. Perhaps the Corsa is more sensitive to alignment and resultant temperature imbalances?

Thanks for your impressions and advice, good or bad--or more accurately, favorable or not.
Old 11-07-2004 | 08:43 PM
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Well, if you have the same problem on the rears, it's almost certain you're not running enough negative camber for R-compound tires. These things need at least -2 degrees to perform properly. As to the pyrometer, I suggest you get one with a probe you can poke the rubber with. The infrared ones are not as accurate. From the pics, I'd say that these tires can still be used, but I strongly suggest you keep an eye on them every so many laps. Good luck!
Old 11-07-2004 | 11:40 PM
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Viken, if nothing else the engineers can look at the pics and make recommendations. They may say "you fried them" but the next time you can do X to prevent it. I like the P-Zero Corsa but I have never seen a set wear like that. It does appear there could be a mechanical problem but the picture makes it hard to tell.
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Old 11-08-2004 | 10:20 PM
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My questions:

How hot was it (track & ambient temp)?
Were they shaved?

It sounds like you bought them from Discount tire. The last set of Corsas I bought from Tirerack, they called me to recommend shaving. I had similar problems with my fronts. I also saw two other cars at a DE at Laguna Seca have similar issues. For the whole story go here:

https://rennlist.com/forums/racing-and-drivers-education-forum/96718-wear-and-ballance-993-turbo-pirelli-pzero-corsa.html



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