Pirelli Corsa's - Left Front uneven tire wear

[PeteInCT]

Just got back from a day at LimeRock park. During the third run I noticed some uncommon 'thumping' from the front end, the kind you feel if you pick up some rubber 'marbles' that stick to your tires for a bit. When I got back to the paddock and checked the tires, I see that I had heat blistering on the left front tire, which is now useless. The wear on the other 3 tires is fine and it looks like I have at least 8 more runs in them (2 track days), maybe more. The tires have a total of 19 runs in them (25 - 30 min runs). I have the MM camber plates installed at -2.0 degrees of camber (the max they will go), but it looks like the left front tires need much more for some reason. I was running it pretty hard today and rotating the car a lot, but this still seems excessive to me. You guys have any thoughts? How many track days did you get out of your Pirelli Corsas?

(PS: I met SteveEspo and Rocketman today - Nice to meet you guys in person!)

 

[VoodooBoss]

You're not the first and it looks defective to me. I believe Kendall or one of his friends had a similar problem.

 

[bolecailey]

Keep in mind I don't have camber plates yet but will soon. I will be ordering vorshlags redesign after I get back from the track attack next week . From my experience with other cars and from others experiences with these cars, -3 to -3.5 is usually the sweet spot for front camber. I believe Gary has -2.7 and he was still seeing slight outside front tire wear. -2.0 degrees camber is really just not enough on any car that I have seen that sees a lot of track time.

As far as the Corsa's go, I have seen a couple of people talking about their tires doing what yours did. The reviews on the tires have been mixed. Most people say they are great and one of if not the fastest tire in their category for a couple of heat cycles and then start to fall off and eventually start bubbling like yours did. They aren't known for there longevity.

 

[roketman]

Pete ,
Nice to meet you today! Looking good out there !
The tires suck .I had the same problem.You will be glad when you put the Hoosiers on!They really are awesome!
Best regards,Ron

 

[VoodooBoss]

I believe it's the body/frame that's the limiting factor on camber and not his MM plates.

 

[bolecailey]

I know some people have gotten up to -2.8 degrees on the MM plates and I have seen some people who have only been able to get -2 or so. I will let everyone know what I get out of the Vorshlags, the new design is supposed to have more camber adjustment.

http://www.sccaforums.com/forums/forumid/103/threadid/47484/scope/posts/threadpage/6

There are some pictures of the prototype and some information about them and 3/4 of the way down the page.

 

[nota4re]

Yeah, your Corsas look just like mine and two other friends' after about 1.5-2 track days. The tires are VERY good for 1 day and then they start delaminating just as your pictures show. Personally, I think they are absolutely a JUNK tire. Very expensive - just to get 1.5 track days out of them. The Hoosier's are a very good tire. You will get ~3 track days on them. On a fast course the Hoosier's may have too much grip for the street-compliant LS spring rates but on shorter courses they are very good.

 

[ArizonaBOSS]

Nasty!

Time for some track wheels and NT01s.

 

[Grant 302]

Thanks for posting pics. It's good to see what the LS owners have been disappointed about.

 

[PeteInCT]

I believe it's the body/frame that's the limiting factor on camber and not his MM plates.

Rick - You are correct. My left strut is fully angled towards the engine now. My assumption is that if any more camber was to come from a different camber plate I'd also have to have mods to the opening where the plates mount to. The answer for me is to hog out the holes in the struct I assume. I am going over to Rick Moroso's shop (of Moroso Performamnce fame) here in CT today and have him look at the car and the tires. If anyone knows what to do with car related to this it would be Rick and his team.

As for the tires, I agree this doesn't give me a warm fuzzy on them , especially at the price! As Ron (Rocketman) pointed out at the track, what additional sucks about this is you can't swap the tires left to right. I'm told by authority that switching to 18" wheels isn't necessarily a good idea for a number of reasons, but in any event I'm not inclined to take on those costs right now. I like the way the car handles and I don't feel like it rides 'too high' or rolls too much. Looks like Hoosiers will be next on the LS, but I go to VIR this weekend - not enough time ! I'll need to run on the Conti Extreme Contacts - that's a bummer !

I still have the two rears in very good shape if anyone is interested. I can take pics of wear if you PM me.

 

[adam81]

Pete,

Mine did the same thing..... However you need to lower your tire pressure BIG time! There are little triangles/arrows that point up on the side of the tire. Your wear mark should come all the way to the top tip of it. Just by looking at the pics and trying to remember where the triangles are your wear mark needs to come out more probably by .5 - 1 inch....

 

[PeteInCT]

I was running 40 to 41 lbs hot per spec. Ill need to check the triangles today....

 

[adam81]

I usually go by the wear pattern to determine hot tire pressure. Generally the recommendation is just a guide, but your tire wear is the most important factor to go off of. Is Lime Rock very hard on the front left tire in general? From looking at the other tires in the pics, and assuming those were the ones tracked, it would suffice to say it is... Another factor in the premature wear may have been from to high of a hot tire pressure. When the pressure is to high it will "donut" the tire wearing out the center. Your other blisters are right on the edge wear mark. If you ran lower pressure and moved the wear mark out more it may not have blistered as bad ??? Like you said the other tires look like they have a ton of life left.

However there are a lot of reports of these tires delaminating.... It happened to me on the second day I tracked the car.

 

[bolecailey]

I'm told by authority that switching to 18" wheels isn't necessarily a good idea for a number of reasons, but in any event I'm not inclined to take on those costs right now.

Just curious, but what "authority" told you 18'' wheels weren't a good idea?

 

[Jza1736]

I'd also like to know why 18's aren't good?

 

[adam81]

Generally the concerns about 18s is how it affects roll center geometry. I am not an expert and really don't know much about this.....

This is why a lot REALLY needs to be done when lowering a car. Especially for the front in the Mustang. You are talking about a bumpsteer kit, ball joints, endlinks, maybe bushings, etc. The rear it is lca reloction brackets, maybe lcas, adjustable panhard, upper 3rd links, etc. This is all needed to get the WHOLE suspension dialed back in.

Again I do not know much about this and some of the stuff I listed may or may not be needed. It also depends on how lower the car is made. Hopefully someone much more edumacated than me can step in.....

However my initial thought is if the diameter of the tire on an 18 wheel is the same as the stock diameter on our 19s does it have any effect at all ??? I would think not....... ???

 

[OLOABoss]

Nothing wrong with 18" wheels. Your gearing my change depending on diameter and more speedometer error. A shorter tire will let the car sit lower but will not affect the suspension geometry.

Peter

 

[steveespo]

I am with Adam about tire pressure with the Corsas. I ran them yesterday at LRP with Pete and Ron and at 35 cold I had 41psi hot at the end of the first session. My car was super loose and I could not get the rear settled during that whole session. My times sucked, ran a best of 1:06.58 but really was all over the place. It was only 47 degrees at the time (9:25) so I figured cold damp track, new tires just had to scrub them and get a little heat and it would be better. I actually spoke to Pete prior to his run and scared him with my description of my run on the Corsas. 2nd session same pressures, temp up to 51 deg and the track was dry, a little sun and still could get no grip, a little more consistent with a best of 1:06.08. 3rd session was after lunch break I said WTF and dropped 3 psi out of the rears and it helped alot, the car felt more planted in the rear and I was able to get off of turns 3 and 4 without lighting up the rears. Best time was only a 1:05.80 but nothing more than a 1:07 even in traffic. I think getting them down to 30 psi cold/35 hot front and rear will be my next experiment to get more grip. I still am not sold on these tires as I ran 1:05's on my stock P Zeros but that was on 75-85 degree days with a seasoned track. I had no blistering or chunking but the wear on the fronts was high up on the edge just like Adam describes.

BTW I clocked Pete during his 3rd session and he was putting down 1:04's like clockwork with a best I had at 1:04.45, Ron who was driveng the Nissan GTR Lime Rock 'Ring taxi also was lapping in the low 1:04's with a 1:03.76 as a best of the 8 or 9 laps I clocked. This with a different passenger every 2 laps and him driving up the back of a Ferrari 458 a couple times.
It really was fun being there with guys from the forum as well as a few other guys I know from last season. I am going to get a ride with Ron in his '13LS which he says is coming the 15th. He has 2 great cars (the GTR and a Ford GT) but he is super jazzed about the Boss, just shows what a great car Ford put together.


Steve

 

[PeteInCT]

BTW I clocked Pete during his 3rd session and he was putting down 1:04's like clockwork with a best I had at 1:04.45, Ron who was driveng the Nissan GTR Lime Rock 'Ring taxi also was lapping in the low 1:04's with a 1:03.76 as a best of the 8 or 9 laps I clocked. This with a different passenger every 2 laps and him driving up the back of a Ferrari 458 a couple times.

Steve

If you had me at 1:04's consistently the I'd say check your stopwatch ;D Great meeting you Steve, we should hook up again soon.

I agree I need to lower pressure, I was running 40 - 41 hot - I will try 35 psi at VIR this coming Monday. I wasn't having a major problem with my rears hooking up at all actually (however I would say I was only pushing the car to about 80% of my own abilities, I'm still babying it a little - nannies still on), but I did have issues with understeer in the Lefthander. I would have gotten more grip if I was at 35 psi hot I believe. As for the Corsa's, even if they were a GREAT tire they are too damn expensive. I am replacing the LF tire with a new Corsa so I can burn up the tires as a set. I'm taking Ron's advice (Gary's too) and going with Hoosier R6's after that. I assume they make them in the 19" sizes....

I have some videos in the can from yesterday that I'll post soon....

 

[PeteInCT]

At LRP yesterday with Steve and Ron (No one has any pics of Ron becuase he was driving too damn fast):

Looks like I lowered the front springs ;D No wonder that tire was getting chewed up.