Grand Sport GY Tires on GS is BS

[DGVETTE]

Pfadt Corvette Alignment Guide

Does anyone know anything about the referenced website...never heard of it, but I'd like to see their take on it.

The website is "pfadtracing.com".
Pfadt Race Engineering

On their technical page
Pfadt Race Engineering » Technical Information

is "Corvette Alignment Guide".
http://www.pfadtracing.com/blog/wp-...09/Corvette-Alignment-Guide-Rev-9.12.2011.pdf

The guide shows alignment settings from Performance Street(mild) to Dedicated Track Car(wild).

 

[catbert]

Good job, thanks.

 

[CentennialGS]

Good news story on the GY tire

I had a flat on my rear passenger tire and took it to the local shop to get it patched, still plenty of thread left. They quoted me $30 to get it, i just wanted to get it done and over with so i agreed. Quoted 1 1/2 hours to do, i was like "really that long?" so right before they started, the manager called them off from doing it. He explained that those tires require a certification to be worked on, and if they did the job, it would nullify the tire's warranty. So they sent me to America's tire.

I went there, they had me in and out under 40 minutes and on top of that, it was FREE due to the tire's warranty.

i am one of those that will still change the tire to another brand when it's time to change it, but was pretty happy with how all that turned out. Turns out i had some sort of heavy duty staple on the tire, dead center. they were able to patch from the inside along with a plug outside.

 

[catbert]

Any Discount Tire will patch it free.

 

[catbert]

The website is "pfadtracing.com".
Pfadt Race Engineering

On their technical page
Pfadt Race Engineering » Technical Information

is "Corvette Alignment Guide".
http://www.pfadtracing.com/blog/wp-...09/Corvette-Alignment-Guide-Rev-9.12.2011.pdf

The guide shows alignment settings from Performance Street(mild) to Dedicated Track Car(wild).

Thanks, I got the Grand Sport realigned to the recommended specs. Hope to get a few more miles before they go to the cord on the inside!

 

[the boss]

agressive wheel alignement spec.

I everyone, I am a new member and this is my first post/reply. I am a mechanic and just bought my first vette, a 2012 zr1 centennial canadian edition (very low production), I was so excited when the delivery truck arrive, I could not stop my legs from shaking.
I was very surprise that after 30 minutes driving I had pain in my back and shoulders. At first I was so nervous to drive it I thougt that the probleme was comming from a high level of stress due to the fact that I use to drive a Grand Caravan and a s60 Volvo and that the vette is way more responsive than the others. But after driving for two weeks, I almost started to look for a doctor. When I was driving, I had to hold the steering whit both hands and keep my upper body pretty stiff to be ready to any reactions from the car at every little bump or any other small imperfection off the road (here in Quebec, the roads are not always like bowling alley).
After 900 kilometers (550miles), I took it on my alignement lift and check the readings. Did a little research on the net and found out that I was not alone and that many owner have had there car alignement whit less ''track ready'' specs. The car was -1.0 dergree negative camber on 4 corners and the front tires where already showing a little wear on the inside. As there is planty of adjustement and I don't go on the track whit the car, I reset the camber to -.5 degree on all wheels and kept all the other specs the same. Huge difference, the car was way more civilize and my wife could drive it but still after 1 hour driving it was again a little painful. I took it back on the alignement and set it at -.25 degree at 4 wheels. I can now drive the car whit one hand and enjoy a 2-3 hours trip whit no pain (and pleasure). Some might think that I may loose handling, but the car and the tires are so great and accordind to the way I drive (pretty smooth) I can only see positives points.
The car is now 2100 kilometers (1300 miles) and I check my tires often, no more degradation + I am also shure that they will live much longer.
English isn't my first language so I appologize for grammaticals errors but I am shure that you will understand the meaning.

 

[1analguy]

Apologize for nothing. Your English is better than some of the other "English" that appears on here. Enjoy that ZR1. It must be nice...

A proper title for this thread would have been "Track Alignment On GS Is BS For Street". Why blame Goodyear for giving GM exactly what they asked for, or for GM's choice of alignment specs?

 

[CentennialGS]

Outer wear on fronts???

I just replaced the stock rims a couple of days ago, my car is sitting at around 6600 miles, when the tires were unmounted, the tech came to me and brought me over to the tires and pointed out wear on the outer portion of the tire (positive camber, really GM??) I saw it and was like, WTF!!! I called my local dealer and told them, currently have an appointment for saturday morning, but somehow I got this feeling that the car will be "within specs" and they will try to charge me for something. I took my car to this same dealer at the 5k for the initial oil change and none of this "wear" was pointed out to me at the time or in the paperwork of their supposed 20 some point inspection. Regardless they always check tires and breaks because that means money to them. no tire wear was documented at the 5k service.

Bought a 2012 Centennial Ed GS and was told by the dealer that they were told by Chevrolet not to align until 5-7K miles. My right rear tire was showing wear,so I took it in at 8K. Dealer said car was in alignment, but that tire would wear the fastest due to it is the power wheel (let's see limited slip, positivetrac......maybe not!). After venting with my local car club, I see a trend with GS owners on premature tire wear. Some have had all 4 replaced and others justa set, but had to get the GM Rep involved. I'm going back this week and insiston some action.
If they won't acknowledge, while my car is on display at our national event, I'll make sure there are mirrors on each tire with placards annotating tirebrand, mileage expectancy, dealer name, service manager and dealership manager.And of course information on links on different Vette forums denouncing these tires and alignment specs.

Maybe after Eli Manning puts about 5-7K on his GS, he'll be a spokeperson for US! :duh View attachment 8177View attachment 8178

 

[Hib Halverson]

I'm looking at C6's and I've been noticing comments regarding tire wear, or tire problems in wet conditions especially with the wide bodies such as the Z06's and Grand Sports.

I read one of Hib's posts from earlier this year when he bought his new Z and swapped out the stock tires with P2's after picking up his car for the ride back to CA.

I might be looking at a new GS this weekend and I'm not sure I'll be able to pull a tire swap off after spending so much $$ on a new car.
I won't make it a habit of driving in the rain but the tire wear concerns me as putting new tires on a brand new car would be a hard one to pull off with the wife - even though I understand.

What is GM doing to help out with this problem - if anything?

I know I'm about five months late in commenting on this but, I never changed the tires on my '12. I posted that I was considering going to PS2s after the PS2 Cups wore out, but I never did it. With 5000 miles on the car so far, the Cup tires have lasted far longer than I expected. I've got about half tread life to go. Considering the amount of miles we put on the car, another set of Cups is a possibility. On the other hand, we're going to use that car to lead the Caravan from California to B.G. in 2014 and for that trip, I will definitely have PS2s on the car in case of bad weather.

As for wear of the Goodyears on GSes...tire wear is a function of many things, design and quality of the tire only being two of the factors. The others are driving habits, pressures and alignment. My belief is that GM is pretty sloppy on alignments at the factory or the cars often have a significant change in alignment in the first couple of thousand miles. Either way, I hear of a lot of cars with the alignment off early in the car's life. My '12 was out of alignment at the 5000 mile mark. Interestingly, it was just inside the camber tolerance for warranty repair so I paid the dealer to reset the alignment to the specs in the FSM. Far as I'm concerned GM's "tolerance" is excessive, considering the cost of the tires on the car, because I had camber in the rear which was different from side-to-side by almost half a degree.

Another wear related issue which I think is critical with Grand Sports is a lot of people who are buying them with the F1 Supercar EMT tires, are not aggressive drivers and do not drive the car hard enough to really need the aggressive alignment that GM uses. On a GS with Supercars which is not driven hard, the owner is best to reset the alignment with less negative camber front and rear. That will do a lot to mitigate abnormal tire wear on the inside of the tread.

On the other hand, if you have a GS Manual with the dry sump LS3 and you autocross, occasionally do track days or just haul ass in twisty roads, think twice about making an alignment change for the sake of tread life because you'll loose some of the car's handing edge.

 

[JJS]

Thanks for posting.
I'm still in the market for a '13 and I plan on (hopefully) purchasing in the next couple of months - I really appreciate all the information I can get regarding tire issues.

-John

 

[Hib Halverson]

If you're buying a '13 you'd better not wait that long. MY13 is going to end early and pickins might be slim if you wait until the Spring or Summer. If you're going to order a car you'd better do it now.

 

[lqueral]

junk tires

Just got my 13 GS manual tranny and magnetic selective ride w/dual mode exhaust. Have the Goodyear Supercar 2nd gen tires and they are WORTHLESS in 40 degree weather. That being said, I always had my Vette stored by Thanksgiving Day so I haven't done much driving in cold weather, but I got the 13 two weeks ago and I was NOT gonna store that right away!! Yes, I realize these are extreme perf SUMMER tires, but I cannot floor it anywhere in 1st gear or midway through 2nd without serious wheelspin. I do not feel safe with these junks under there. Nowhere does Chevy say this car is not to be driven in sub-40 weather and let me tell ya, it feels like I'm on a freakin roller coaster with these things. I now have 300 miles on them and that should have worn off the shiny rubber by now. Air pressures are set cold to 31 lbs cold. I love the car, but I can only hope this situation improves DRAMATICALLY in the Spring and 60+ temps. Anyone else have this issue?

 

[Hib Halverson]

Any "extreme performance summer" tire will perform as do the Goodyear F1 Supercar EMTs in 40° weather.

If you want better traction in cold weather, put winter tires on the car.

 

[Tuna]

Just got my 13 GS manual tranny and magnetic selective ride w/dual mode exhaust. Have the Goodyear Supercar 2nd gen tires and they are WORTHLESS in 40 degree weather.

I'd had my '13 427 Vert with the Michelin PS2 tires for a few months now and they ain't any better in 40-degree temps either. I have similar issues with PS2's on my CTS V and previously with the GY SuperCars on my old CTS V.

Like Hib said:

"Any "extreme performance summer" tire will perform as do the Goodyear F1 Supercar EMTs in 40° weather.

If you want better traction in cold weather, put winter tires on the car. "
​

Wait until there's snow or ice on the road - talk about an "E" ticket ride! (I'm showing my age here.)

 

[lqueral]

slippage

Any "extreme performance summer" tire will perform as do the Goodyear F1 Supercar EMTs in 40° weather.

If you want better traction in cold weather, put winter tires on the car.

As I said, this generally would not be an issue with me due to winter storage, but I kinda can see what the wags at Motor Trend were writing about months ago when they blasted the Grand Sport when they pitted it against the Porsche. They claimed they even had trouble keeping up with a minivan. I'll be covering it soon for rest of Winter so I'll re-assess in Spring, but I likely will consider a Michelin EMT when time comes to replace...and that might not be in too long a time based on what I'm reading here <pained grin>.

 

[the boss]

Same here. I have michelin ps2 on my 2012 zr1 and the last week of November, before putting the car in storage for winter, I took it for a ride on a nice weekend and scare the sh...out of me, by myself. The difference in traction in unbeleivable. Tire slippage VERY easy, To easy. It was close to 0 celcius (about 34-35 F). Did my little ride very smoothly and put it away before desaster strike.

 

[Tuna]

With the ZR1 and the 427 Vert (which has the ZR1 size wheels and tires), finding a good all season (winter) tire is going to be tough. Lucky for me, Oklahoma winters aren't all that bad most of the time.

 

[CentennialGS]

To address what Iqueral was saying, most reviews you will find online for this tire aren't very positive, and that will include SoCal drivers, it's basically summer year round down here. I just took mine in to get the alignment checked this past Saturday, they did confirm it was "out of range" for the fronts but the rears were within range. I'm not a big fan of "range" when it comes to an alignment but it was done under warranty so i did not have to pay a dime for it. The car is at 6600 miles and my rears are about 4/32 left, I definitely won't replace with the stock tires, I will prob use Michelins. Recently we have been having light rains and i have to be very careful in 1st and 2nd gear, because my tires will spin out very easy with the light rain on the road. It is scary to the point that I do not drive it even with a light drizzle outside, my rear has spun out from under me in many occasions, even in the dry road, but I would attribute that to the current wear level of the tire, earlier in the year when I got the car in late March, those summer months, grip was ok, not excellent, but ok.

What is al ittle troublesome is the fact that when it was getting aligned this weekend, I asked for specific measurement front and rear and the dealer would not, instead they would use the OEM range since it was a warranty issue, but the spec i asked for was within the range of OEM, go figure. I also asked to be provided a copy of the specs, I didn't get it, but I also didn't check when I left the dealer.

 

[Tuna]

Well, my experience with the GY SuperCar tire (not on a Vette but a 1st generation CTS V) is that they wore out way too fast and basically sucked in the rain. Great dry traction however - maybe a bit too much with the V1 as it tended to wheel hop with a hard launch. I replaced the first set of SuperCar tires with another set with the same results - ~13K miles and they were gone also. I've heard similar stories from Vette owners with the SuperCar tires.

As for my V1, I found a tire with nearly as good dry performance, excellent wet weather performance, good winter performance and more than twice the life - they were GOODYEAR tires also: The F1 GS D3 and in EMT. Too bad GY does not make the D3 in a size that fits the C5 and C6 in all the different tires sizes they use. If they did, I'd give them a look when it comes time to replace tires.

The C6 gofaster versions all get Michelin Pilot Sport 2 tires. I've only got 6 months on my 427 Vert now so I have no idea how long they will last. Driven them in the rain and, while not great, they are not all that bad. They, like the SuperCar tires, don't stick to the road well when the tire/road is cold - like < 50 degrees. Nothing new there.

I do have 2 years experience on my Michelin Pilot Sport 2 tires on my CTS V (V2) Wagon. 15K+ miles now and still showing good tread. They are okay in the rain - even now. They aren't any better in the cold.

With my previous Vettes (narrow body versions), I replaced the GY tires (not SuperCar tires) with Michelin PS All Season ZPs and was pretty satisified with them. The AS ZP gives some away in summer performance to the summer tire but does not loose much when cold.

Now that both my performance cars come with Michelin PS2 tires, I have the summer months covered but will have to pay attention to the traction when it's cold out. I believe the PS2s will last longer than the GY SuperCar tires and that's good.

I checked TireRack.com and noted that no one makes an all season tire in the ZR1/427Vert sizes. Ditto for the C6 Grand Sport sizes - oh well. I suppose I could buy a custom set of HRE wheels in 19x6 and mount mud and snow tires on them for winter. :L

 

[Hib Halverson]

(snip)

The C6 gofaster versions all get Michelin Pilot Sport 2 tires. I've only got 6 months on my 427 Vert now so I have no idea how long they will last. Driven them in the rain and, while not great, they are not all that bad. They, like the SuperCar tires, don't stick to the road well when the tire/road is cold - like < 50 degrees. Nothing new there.

The C6 "gofaster" versions (ZR1 and Z06) get Michelin PS2s, but the "goevenfaster" versions (ZR1 w. PDE or Z06 w. Z07) get Pilot Sport Cup tires which are basically a run flat casing with a sort of low-tread-depth, racing-rain-tire tread design in a very soft tread compound.

If the PS2s are "not great" but "not all that bad," then PS Cups are "barely acceptable at reduced speed" in light rain and unsafe in anything more than that.