Let's get serious about track tires for GT350

[NvrFinished]

That's a great find! Hope others get to take advantage.

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[zzrat]

I'll put a little spin on this topic as to the "experienced" to the "novice" side. We were unable to track our car this past summer & really looking forward to spring of 19' here in the midwest. This will be the first experience of any type of tracking a car let alone a HP gt350. So I visited again the website for the " 10/10ths Motorsports " recently . They're an outfitter here in the tri-state In,Ky,OH that has track days at a handful of tracks in the region. Their wording for the novice run group is to stay on street tires. For the novice to learn handling of their car as they stated that street tires are much more forgiving than a track tire.

Well with this being said let's hear what "street" tire would be the choice from you folks that do have the experience of tracking a 350. TIA

 

[Trackaholic]

I'll put a little spin on this topic as to the "experienced" to the "novice" side. We were unable to track our car this past summer & really looking forward to spring of 19' here in the midwest. This will be the first experience of any type of tracking a car let alone a HP gt350. So I visited again the website for the " 10/10ths Motorsports " recently . They're an outfitter here in the tri-state In,Ky,OH that has track days at a handful of tracks in the region. Their wording for the novice run group is to stay on street tires. For the novice to learn handling of their car as they stated that street tires are much more forgiving than a track tire.

Well with this being said let's hear what "street" tire would be the choice from you folks that do have the experience of tracking a 350. TIA

I've been running the stock Pilot Super Sports. I am an experienced driver, but not very talented. When we did the GT350 track day at Buttonwillow, I was several seconds off of Honeybadger's pace. I do push the car a bit, but definitely keep slip angles in check, which really helps with front tire management. I can get ~20,000 miles and three track days out of a set of the stock PSS tires.

Here is a chart that gives a general idea of grip VS. slip angle. As you can see from the green, "street tire" line, there is a large plateau where you will have roughly the same grip even as you turn the wheel more and more. I definitely drive more on the left side of that slope.

If you start really pushing the car and start getting understeer, you are at the limit of grip and therefore at (or beyond) that flat part of the curve. This will very quickly cause rapid tire degradation for no benefit. Once you start hitting that point you need to back off and adjust your driving style in order to keep wear in check. Incidentally, you can also see that with too much input, grip falls off, which is why you often need to unwind the wheel when you start to understeer.

In any case, I am on my second set of PSS tires, but will likely go to the 4S when these run out.

-T

 

[honeybadger]

Hey Rex -

Great question. While I am not the most experienced driver here by far, I did spend the first 16 track days in my car on super sports. I then switched the 305 Cup2s and ran through (3) sets of them (12 days worth of track time).I can without a doubt tell you that you will learn FAR more on the super sports in the beginning. They won't hide mistakes as much, they don't let you get away with nearly as much, and they're MUCH cheaper. 8-10 days out of a set of fronts vs. 4 for the cup2s.

My first track day on the cup2s, I was (6) seconds a lap faster in my first session. R compound tires (such as the Cup 2s, Trofeo Rs, R88Rs, etc.) are so much easier to go fast because they're just so much stickier. They hide mistakes and allow you you to push much harder than you would be able on street tires (harder doesn't necessarily mean faster).

I've spent the last (3) days on Super Sports again and it's been very eye opening on how much I had started to lean on the extra grip from the Cup2s to be fast. Going back tot he super sports really helped me clean up some of my driving. Now I can't wait to get back to COTA on the Cup2s to put into practice what I've learned.

 

[LAPTIMZ]

I had time (and enough coffee) to geek out on specs of top performing, commonly cross shopped and comparable tires. I pulled up manufacturer specs from the following:

305/19 Goodyear F1 Supercar 3R

305/19 Michelin Pilot Sport Cup 2

305/19 NT01/R888R

315/19 Hoosier R7

And here is what I have found re: relevant (arguable) specs such as weight, tire width, tread depth, tread width etc. Now, the cost will obviously vary however this provides a basic baseline for comparative purposes. Personally, I like to know the size of my overall contact patch, weight, tread depth etc. I grouped the NT01 with the R888r because there was limited information on the NT01 and the R888r is made by the same manufacturer and is the most closely comparable tire. I know the UTQG means absolutely nothing but at least it helps group the tires somewhat. Most noticeable value, besides cost mentioned below, is the weight. I thought the 3r's were light but evidently they are heavier than MPSC2 which I found to be surprising. But the tread width is more like a 315 than a 305.

305/19 Goodyear F1 Supercar 3R

COST: $344.99

UTQG: 100AA A

Tread Depth: 5/32”

Tire Weight: 29 lbs

Section Width: 12.3”

Tread Width: 11.8”

Overall Diameter: 26.3”

Revs per Mile: 796



305/19 Michelin Pilot Sport Cup 2 (GT350R spec)

COST: $400.53 (per tire)

UTQG: 180AA A

Tread Depth: 5.5/32”

Tire Weight: 26 lbs

Section Width: 12.3”

Tread Width: 11”

Overall Diameter: 26.3”

Revs per Mile: 792



305/19 NT01/R888R

COST: $419.00-429.88 (per tire)

UTQG: 100AA A

Tread Depth: 6.3/32”

Tire Weight: 31 lbs

Section Width: 12.3”

Tread Width: 11.8”

Overall Diameter: 26.3”

Revs per Mile: 791



315/19 Hoosier R7

COST: $489.02 (per tire)

UTQG: 40 C A

Tread Depth: 4/32”

Tire Weight: 27 lbs

Section Width: 12.5”

Tread Width: 12”

Overall Diameter: 26.1”

Revs per Mile: Not Listed

 

[LAPTIMZ]

Lastly, an update on my tires (Goodyear F1 Supercar 3R) after Laguna Seca. The added camber made really helped save my tire wear on the outer edge. I managed a 1.39 (predictive 1:37 which shows how much traffic there was that day) on a good clean lap chasing a very well driven and setup F80 M3. The tires have been consistent and solid the entire day. I just wonder what the limit is on heat cycles with a tire this cheap and grippy. I guess I will find out at the next track day. I got another 4-5 heat cycles on these bringing the total up to about 9-10. It takes a solid 2 laps to get them up to temp and they maintain their grip until I run out of gas.The only problem I foresee is no matter how cheap they are, I can't justify new tires every 3 track days as compared to an NT01 where I may get 6-8. Additionally, with the NT01, I know I have grip until they cord regardless of heat cycles.

 

[honeybadger]

The only problem I foresee is no matter how cheap they are, I can't justify new tires every 3 track days as compared to an NT01 where I may get 6-8. Additionally, with the NT01, I know I have grip until they cord regardless of heat cycles.

This is my main concern as well. Tires that are cheap and last (3) days work out great for those who buy a set of tires for the big events they go to. But if you're trying to maximize value + longevity, it's a bit harder to justify. Especially if you stack (2) events up and you run out of tire on day 3 of 4.

So far, I've personally seen the performance + longevity of the Porsche spec tires. They seem like the best compromise on our car. I plan to try NT01s next just to add a data point, but so far feeling the Porsche spec tires are the preferred R compound for this car.

 

[oldbmwfan]

Lastly, an update on my tires after Laguna Seca. The added camber made really helped save my tire wear on the outer edge. I managed a 1.39 (predictive 1:37 which shows how much traffic there was that day) on a good clean lap chasing a very well driven and setup F80 M3. The tires have been consistent and solid the entire day. I just wonder what the limit is on heat cycles with a tire this cheap and grippy. I guess I will find out at the next track day. I got another 4-5 heat cycles on these bringing the total up to about 9-10. It takes a solid 2 laps to get them up to temp and they maintain their grip until I run out of gas.The only problem I foresee is no matter how cheap they are, I can't justify new tires every 3 track days as compared to an NT01 where I may get 6-8. Additionally, with the NT01, I know I have grip until they cord regardless of heat cycles.

Just to clarify (trying to track your posts through the thread) - this is with the Goodyear F1 3R?

Thanks.

 

[LAPTIMZ]

Just to clarify (trying to track your posts through the thread) - this is with the Goodyear F1 3R?

Thanks.

Crap...sorry....yes it is. I updated my post

 

[firestarter2]

Hey Rex -

Great question. While I am not the most experienced driver here by far, I did spend the first 16 track days in my car on super sports. I then switched the 305 Cup2s and ran through (3) sets of them (12 days worth of track time).I can without a doubt tell you that you will learn FAR more on the super sports in the beginning. They won't hide mistakes as much, they don't let you get away with nearly as much, and they're MUCH cheaper. 8-10 days out of a set of fronts vs. 4 for the cup2s.

My first track day on the cup2s, I was (6) seconds a lap faster in my first session. R compound tires (such as the Cup 2s, Trofeo Rs, R88Rs, etc.) are so much easier to go fast because they're just so much stickier. They hide mistakes and allow you you to push much harder than you would be able on street tires (harder doesn't necessarily mean faster).

I've spent the last (3) days on Super Sports again and it's been very eye opening on how much I had started to lean on the extra grip from the Cup2s to be fast. Going back tot he super sports really helped me clean up some of my driving. Now I can't wait to get back to COTA on the Cup2s to put into practice what I've learned.

I think ill go the cup 2 porsche spec. I have heard of some quality control issues with the NT01 but who knows how accurate that is. If I can get 8 days on a tire I am happy with that if I factor weather and random bullshit that always happens that basically a season for me.

 

[svttim]

Hey Rex -

Great question. While I am not the most experienced driver here by far, I did spend the first 16 track days in my car on super sports. I then switched the 305 Cup2s and ran through (3) sets of them (12 days worth of track time).I can without a doubt tell you that you will learn FAR more on the super sports in the beginning. They won't hide mistakes as much, they don't let you get away with nearly as much, and they're MUCH cheaper. 8-10 days out of a set of fronts vs. 4 for the cup2s.

My first track day on the cup2s, I was (6) seconds a lap faster in my first session. R compound tires (such as the Cup 2s, Trofeo Rs, R88Rs, etc.) are so much easier to go fast because they're just so much stickier. They hide mistakes and allow you you to push much harder than you would be able on street tires (harder doesn't necessarily mean faster).

I've spent the last (3) days on Super Sports again and it's been very eye opening on how much I had started to lean on the extra grip from the Cup2s to be fast. Going back tot he super sports really helped me clean up some of my driving. Now I can't wait to get back to COTA on the Cup2s to put into practice what I've learned.

I agree with HB, you will learn better on the original tire rather then rely on a super sticky set of tires. That being said, I am always looking for feedback from the car as to how much I can push it regardless of the tires on the car. Even in a 20 or 30 minute session, expect to see a low grip (cold tires) Maximum grip then tire fall off. Depending on the cars handling and your aggressiveness, these can happen at different times. More important to know your car and its limits then how sticky tires are. Of course, seat time is king

 

[Paul@PKAUTODESIGN]

I run a 325/30/19 Toyo R888R tires on my vehicle

Amazing daily driver and great on the track.

Very sketchy in rain however.

 

[Schu]

... great thread/info

 

[havasu486]

Nice! How do you like them compared to the NT01s? OEM r sizes?

Mind filling this out for your Nittos experience?

• Event type/run group: HPDE, Intermediate/Advanced depending on the group
• Number of sets: 1
• Driving style: Aggressive, getting smoother
• Days lasted: 10 HPDE Events, 14 additional heat cycles to track
• Did you rotate: Yes, 305/30/19 Nitto NT01 squared on Apex 19x11' EC-7 Wheels
• Tire pressures: 27-28 cold to 35-36 hot
• Camber: -1.9 is all I can get with current set up. 2019 will start at -2.5
• Tracks: Autobahn Country Club Joliet IL, GingerMan South Haven MI, and Road America Elkhart Lake WI.

I am on my second set of NT01s. Initially the purchase was based on cost. They are a square, track dedicated, setup although my home track is less than a half hour away from the house so seven of ten sessions included travel to the track. I ended up replacing them not because they corded but because I heat cycled the goodie out of them. I highly recommend taking tire temps with a probe and not a surface scan.

The NT01 is a great entry level tire for the money. I have found them for $400.00 each time. Once I can trailer my wheel/tire and my skills improve I'll consider a slick. They are very poor in the wet.

 

[Zitrosounds]

So, I am strictly a Michelin man (MPSS's, P4S's SC2's) becuase in my opinion they are the best street tire and street/comp tire. I own an R and stick pretty close to the FP spec (+/- .5) because it seems to suit my driving and works well with he CF wheels. I believe the wheels used should be included with tire selection as the material/mass/design in wheel construction varies from one brand wheel to another. The loads imposed on the tires are greatly affected by the flex (deflection) in the wheel. An aluminum wheel can only get so light. Deflection is limited by the sheer reduction in mass (material) regardless of design. So a wheel like the CR CF wheel on the R vs the Forgelines used on FPS and GT4 cars will have less deflection. This is why the OEM GT350 wheel is so heavy. To reduce deflection the GT350 makes up in mass due to production manufacturing cost. Just remember, you can only add some much neg camber before you start upsetting other handling characteristics due to suspension geometry and chassis bushing deflection.

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