Stingray Corvette Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
11 Posts
Discussion Starter #1
Track Days Alignment 2015 Corvette C7 3LT Z51 7 sp - With Michelin Pilot Sport Cup 2 Tires

I have been on the Corvette Stingray Forum for the past several years, but I have not been that active on posting. I find it a good source of information, but couldn't I find info on Track Days Alignment specific to a C7 Z51 with Michelin Pilot Sport Cup 2 tires.

I am an Automotive Engineer who specialized in Brakes and Suspension and Vehicle Dynamics.

I have raced Spec Miata and then open wheel Formula cars with SCCA for 10 years. Then I raced with NASA in Track Days with a 2004 BMW M3 in Time Trial for 4 years until I bought a Corvette.

I bought a used 2015 Corvette Shark Grey C7 3LT Z51 7 sp loaded with PDR and Magnetic Ride Control shocks. I have been doing Track Days events with NASA, MVP Track Time and Laps Inc. for the past 4 years.

I have from GM the 2014 - 2018 Corvette: Service Bulletin: #16-NA-056: Track and Competitive Driving Wheel Alignment Tips - (April 4, 2017). This bulletin requires removing 1 washer per front and rear upper control arm. Be advised this Track Alignment is a costly process approximately $550.00 at Martin Chevrolet).

But, I thought I would take one for the Team as an experiment and see if it is worth it?

Why, because the cost of a set of Michelin PSC2 tires last season in 2019 was about $1,850 and I only got about 15, 30 minute sessions at Road America, Autobahn Country Club and NCM before I had severe outside shoulder wear and chunking especially on the front tires when running stock alignment and 26 PSI cold tires pressure to start.

TSB - Alignment Specs
Front

Caster: + 7.0 degrees
Camber: - 2.0 degrees
Toe: 0.05 degrees toe in

Rear
Caster: 0 degrees
Camber: - 2.0 degrees
Toe: 0.05 degrees toe in
Thrust Angle: 0 degrees

So, my question was if you use the GM Track Days alignment specs is the car drivable on the street or is it really darty when driving to and from the track.

In fact it is both great on the street and on the track as I have run 3 HPDE4 events this year at Blackhawk Farms Raceway, Autobahn Country Club Full Course and Mid-Ohio this year. Tire wear on the outside shoulder is much better after 16, 30 minute sessions.

I'm hoping this information is useful for you Track Rats that do a lot of Track Days Events and hope to go FAST and get quicker lap times.

Cheers,
Terry #14 T-Bone
 

·
Administrator
Joined
·
15,889 Posts
Thanks Terry, for your being a 'beta' tester and for sharing your results.
 

·
Registered
Joined
·
10 Posts
Terry,
Thanks for an interesting article. I only did one track day, at Summit Point Raceway. It was a lot of fun but my 2014 was and is a car I use often and when I started to think about the added expenses of insurance, tires, etc. I decided it wasn't for me.
On the topic of tire wear, I have had my rear tires since I took delivery in Nov. 2013. I am at 33k plus change miles now and I need to get new ones as tread wear markers are starting to get close to the tires surface. The front tires needed replacing at 16K. miles, which I did and now they are also in need for replacing.
My question is, have you heard anything about an adjustment that is suggested or needed to increase the front tire wear, for regular street driving, not tracking?
Thanks,
Marty
 

·
Registered
Joined
·
11 Posts
Discussion Starter #4
Marty,

Glad you liked the article. I know the extra expense of tires, brakes and insurance can get pricey for Track Days events, but glad you enjoyed the Track Day at Summit Point Raceway!

On the issue of tires I have a couple of questions for you first before I could make a recommendation.

1.) Is your Corvette C7 Stingray a base model or the Z51? Front & Rear OEM wheel size is important for finding replacement tires.
Base 2014+ C7 Stingray Corvette wheels are size 18 × 8.5 in the front and 19 x 10 in the rear. The recommended tire size for the Stingray wheels is 245-40-18 front and 285-35-19 rear.
Z51 Models are Front: 19-inch x 8.5-inch, Rear: 20-inch x 10-inch. Tire size recommended for the wheels are 245/35 ZR 19 (F); 285/30 ZR 20 (R) Michelin Pilot Super Sport ZP run-flat Tires.

2.) Do you live in a cold climate and drive in cold temperatures below 40 degrees F?

Regardless of what replacement tires you choose the main thing to have your alignment shop or GM dealer set it to the OEM factory settings and make sure they get the Camber & Toe-In correct. Incorrect Toe scrubs the tires every mile you drive and prematurely wears the tires. Incorrect or excessive Camber like the Track Days Alignment I showed will wear the inside shoulders prematurely.

My reason for asking about your Corvette is that for the 2020 C8 Corvette new tires were developed for the car and may be worth a look if available for you vehicle. I would consult Tirerack.com and get their opinion on putting the C8 tires on a C7 or their best option for your needs and driving conditions.

Read below for reference from GM Authority

2020 Corvette Gets All-Season Tires, Still Manages 1G | GM Authority

For those who may be out of the loop, the base 2020 Corvette Stingray rides on the freshly-developed Michelin Pilot Sport ALS compound, staggered front to back with 245/35R19 slabs in the front and 305/30R20 meats in the rear.

Meanwhile, upgrading the 2020 Corvette with the optional Z51 package swaps the all-season ALS rubber for the Michelin Pilot Sport 4S – a summer-only max-performance compound that’s unsuitable in cold conditions. But the tradeoff from all-season practicality on the stickier Pilot Sport 4S compounds increases lateral grip even further, generating between 1.03 G and 1.05 G.

It’s believed that Michelin’s Pilot Sport ALS compound is essentially an evolution of the existing Michelin Pilot Sport A/S 3+ compound, the tire-maker’s current ultra-high-performance all-season rubber. According to a recent report from Car and Driver, the new compound is dubbed Pilot Sport All Season 4, which makes sense if it is indeed a successor to the current Pilot Sport A/S 3+. Chevrolet and Michelin developed the new all-season tire over a five-year period specifically for the 2020 Corvette.

Despite the all-season nature of the new Pilot Sport ALS, aka Pilot Sport All Season 4, Chevrolet claims the 2020 base-model mid-engine Corvette will still generate “nearly 1G.” This is critical for a high-end performance vehicle billed as a “true supercar for every day.”

“This tire doesn’t make the compromise that a summer tire will make when the temperature drops below 40 or 50 degrees, especially if it’s wet,” said Michelin’s lead development engineer for the new tire, Lee Willard, in an interview with Car and Driver. “It really behaves like a summer tire in balance and progressiveness at the limit, yet it offers two to three times the grip of a Michelin summer tire in the snow.”

Considering the previous Chevrolet Corvette was only offered with summer performance rubber, the all-season rubber on the base model represents a huge jump in usability and practicality for future owners of the C8, particularly those who drive their mid-engine Corvette year-round… though we should note that those who plan on driving in the snow should invest in a set of true winter tires.

Meanwhile, upgrading the 2020 Corvette with the optional Z51 package swaps the all-season ALS rubber for the Michelin Pilot Sport 4S – a summer-only max-performance compound that’s unsuitable in cold conditions. But the tradeoff from all-season practicality on the stickier Pilot Sport 4S compounds increases lateral grip even further, generating between 1.03 G and 1.05 G.

Let me know what you Corvette is and then we can decide what options you have for your driving and conditions.

Cheers,
Terry #14 T-Bone
 

·
Registered
Joined
·
11 Posts
Discussion Starter #6
Marty,

OK so the tire and wheel sizes for your Corvette C7 3LT Z51 are exactly the same as my car.

Front: 245/35ZR19 Rear: 285/30ZR20 and the OEM tires are Michelin Pilot Super Sport ZP (Zero Pressure) Run Flats Tread Wear Rating UTQG: 300 AA A

The 2020 C8 Corvette Z51 tire and wheel sizes are Front: P245/35R19, rear: P305/30R20 and the OEM tires are the Michelin Pilot Sport 4S ZP also Run Flats Tread Wear Rating UTQG: 300 AA A

Tire Rack says you can get the front tires Michelin Pilot Sport 4S in ZP Run Flat, but Michelin does make a rear 4S in the 285/30ZR20 size yet. Not sure if they will develop this range of tire in the 4S ZP Run Flats for the C7.

So option 1 would be to use the OEM tires Michelin Super Sport ZP Run Flats, but Tire Rack says the fronts are on back order from Michelin.

Option 2 could be the Michelin Pilot Sport A/S 3+ ZP Run Flats Ultra High Performance All-Season
Tread Wear Rating UTQG: 500 AA A. While these tires are not as sticky as the Super Sport or 4S they are still a Ultra High Performance All-Season tire and might work well for you.

You are in the same situation as I am because when I need to replace my Michelin Super Sport ZP tires I would look for Ultra High Performance All-Season tire so I could drive my Corvette more in the early spring or late fall when the Temps are below 40 degrees F and the roads could be wet and slippy.

Fortunately for me I have another set of wheels and I have the Michelin Pilot Sport Cup 2 tires with a UTQG: 180 mounted on them for my Track Days events.

Hope the information helps!!

Cheers,

Terry #14 T-Bone
 

·
Registered
Joined
·
10 Posts
Marty,

OK so the tire and wheel sizes for your Corvette C7 3LT Z51 are exactly the same as my car.

Front: 245/35ZR19 Rear: 285/30ZR20 and the OEM tires are Michelin Pilot Super Sport ZP (Zero Pressure) Run Flats Tread Wear Rating UTQG: 300 AA A

The 2020 C8 Corvette Z51 tire and wheel sizes are Front: P245/35R19, rear: P305/30R20 and the OEM tires are the Michelin Pilot Sport 4S ZP also Run Flats Tread Wear Rating UTQG: 300 AA A

Tire Rack says you can get the front tires Michelin Pilot Sport 4S in ZP Run Flat, but Michelin does make a rear 4S in the 285/30ZR20 size yet. Not sure if they will develop this range of tire in the 4S ZP Run Flats for the C7.

So option 1 would be to use the OEM tires Michelin Super Sport ZP Run Flats, but Tire Rack says the fronts are on back order from Michelin.

Option 2 could be the Michelin Pilot Sport A/S 3+ ZP Run Flats Ultra High Performance All-Season
Tread Wear Rating UTQG: 500 AA A. While these tires are not as sticky as the Super Sport or 4S they are still a Ultra High Performance All-Season tire and might work well for you.

You are in the same situation as I am because when I need to replace my Michelin Super Sport ZP tires I would look for Ultra High Performance All-Season tire so I could drive my Corvette more in the early spring or late fall when the Temps are below 40 degrees F and the roads could be wet and slippy.

Fortunately for me I have another set of wheels and I have the Michelin Pilot Sport Cup 2 tires with a UTQG: 180 mounted on them for my Track Days events.

Hope the information helps!!

Cheers,

Terry #14 T-Bone
Thanks again for all the feedback Terry. When I first did the Fat (Friday At the Track) at Summit Point, I was going to get a new or at least another set of wheels and tires, just for the track. Then reality set it. I have a one car garage. A Harley, a Goldwing and the C7 fit in it, along with a bicycle and it is as you might imagine, very full. So I added all that up with the cost of renting a garage and the track insurance, etc and decided it was not for me.

I know one thing for sure, I love driving the C7! I am pretty cautious on the street with it and when conditions allow, I let it run a bit. Never at night because it's tough enough to see the cops in the day time. At night, forget about it! lol At 70, I am just happy to still be able to get in and out of it! lol

Stay safe and enjoy the rest of the weel!

Marty
278002
 

·
Registered
Joined
·
11 Posts
Discussion Starter #8
Marty,

As Clint Eastwood (AKA Dirty Harry Callahan) said in Magnum Force, "A man's GOT to know his limitations."

That's why I have a lift in my garage to keep the (3) cars I have and all the extra wheels, bicycles and tools handy!!

Cheers,

Terry #14 T-Bone
 
1 - 8 of 8 Posts
Top