S197 Boss Lite - 2011 Mustang GT Build Thread Profile - S197 Mustangs

[stevbd]

Mine is an 05, so the GT500 is an upgrade for me, can’t speak to the 11-14.

After a hot session, here that is usually 25 or 30 minutes I have a 7-8 degree spread from 160-168 or so. I don’t know if that good or bad but it works for me, and that’s a 275 at 32 psi hot

Those seem like awesome numbers to me. That’s about what my rears were. I might try copying your alignment numbers up front. I run 305s and 34 psi.

Do you get even wear across the tire width?

Thanks for your help!

 

[Junkyard Dog]

Deleted because I have no idea what I am talking about

 

[stevbd]

I am no expert, but, wow, that looks like a lot of lean in the photo, like your splitter is about to drag on the driver's side.

I wonder if getting the car to corner flatter would help?

Again, I am no expert. Please be aware that I may very well have no idea what I am talking about, and the lean toward the outside on a turn is just perfect. But it looks like a lot to me compared to photos of my car on turns


Ha!

It won't let me copy and paste the photo you posted.

It is your post #30.

Very exciting looking track, by the way.

Yeah it’s set up pretty soft compared to a true track set up, but not super soft. It leans for sure but I think that pic is a little misleading. It’s 400 lb per inch front, 200 rear, cortex coil overs.

My buddy in his GT4 kindly filmed a few minutes of me, you can get sense of lean. Starting at 33.20. Damm that little pcar hatchback is fast fast fast btw….

 

[dave2278]

Wow, some of those drivers seem really not safe, what type of event was this?

For reference my spring rates are 675 front and 550 rear, it’s surprisingly comfortable to drive. Obviously having spring on shock in the rear will change the rates there.

 

[stevbd]

Well it looks like you have a lot of aero, which is a different thing of course for spring rates.

Palmer runs a lot of what they call open lapping days, it’s a pretty hands off format. You get a ton of track time, about 5 hours on the day, and you’re left on your own to use your own judgment. I personally love it, and somehow it all works out. There’s a ton of variety on track at the same time, so you gotta watch your mirrors and have good awareness.

 

[dave2278]

Well it looks like you have a lot of aero, which is a different thing of course for spring rates.

Palmer runs a lot of what they call open lapping days, it’s a pretty hands off format. You get a ton of track time, about 5 hours on the day, and you’re left on your own to use your own judgment. I personally love it, and somehow it all works out. There’s a ton of variety on track at the same time, so you gotta watch your mirrors and have good awareness.

Sounds like an interesting format, I’ve never done a day like that. It’s always been separated into groups based on experience.

5 hours sounds pretty awesome and the track looks like a blast.

 

[Dave_W]

I'm not a tire expert, either. When I looked at the first tire pic, at first glance it looked like Other People's Rubber buildup across the middle & outside, and then the outside shoulder had none because of the negative camber was keeping the shoulder off the track.

What was the procedure when you took the tire temps? Was there a cool-off lap before you took them, or time spent driving in the paddock? Ideally, you want to take the tire temps immediately coming off track from a couple hot laps.

Toe out will typically cause wear on the inside edges of the tire, not the outside. Especially with negative camber. Do you know the camber & toe you're running on track, or are you just going to max from a street setting?

What are your lap times at Palmer?

 

[stevbd]

My friend took the tire temps immediately as I came off track in pit row. No cool down lap.

I don’t know precise toe and camber. Yes, I’m going to max from a street setting. I expect it’s about 3.5 degrees neg camber and a bunch of toe out. I’m no expert but my understanding is that toe out can excessively shock the outside edge on turn in, which combined with neg camber makes cold tearing worse.

Something with this alignment is causing the outside shoulder delamination, it’s happened on every single tire. My outside edge temp at 135 is way below the recommended 160 or so for good 3R performance.

My best laps at Palmer are 1.48s, on this last day I was running about 1.51s. All on 3Rs.

 

[Dave_W]

My friend took the tire temps immediately as I came off track in pit row. No cool down lap

In that case, I'd try using less negative camber. Try to get the temps evened out.

 

[Junkyard Dog]

Deleted because I have no idea what I am talking about

 

[Junkyard Dog]

Deleted because I have no idea what I am talking about

 

[steveespo]

If you move camber you introduce toe out on a modern Mustang chassis. They are front steer cars, as you lean the strut in to give negative camber the spindle pivots on the tie rod link and toes out. The movement is significant and not linear. Easy to get 4-5 mm of toe change. It needs to be checked and set each time you make camber changes. A 40 degree temperature difference inside shoulder to outside indicates scrub as JunkYard Dog mentions. The outer shoulder wear is a feature of the tire as the outer tread compound is softer that the rest for that hybrid track/street designation.

 

[dave2278]

Those seem like awesome numbers to me. That’s about what my rears were. I might try copying your alignment numbers up front. I run 305s and 34 psi.

Do you get even wear across the tire width?

Thanks for your help!

Sorry just saw your question about tire wear, yes they wear very evenly. Here are some pics of the fronts right before I replaced them, still have some tread but heat cycled out.

I got this set at the beginning on the season, ran 18 autocross and 8 track days plus about 1500 street miles.

 

[Junkyard Dog]

Deleted because I have no idea what I am talking about

 

[Junkyard Dog]

Deleted because I have no idea what I am talking about

 

[dave2278]

Wow. I had no idea one could get that sort of longevity out of a 3R in a heavy Mustang.

Mine are not the 3R, just regular 3.

I am not running time trials or anything so I opted for the standard. I’ll probably go with the 3R when I start being more competitive, I still have a lot to learn

 

[stevbd]

All of your heat, that is, the highest temperature, is on the inside, not the outside. You are cooking that inside tread, and barely touching the outside tread, according to the temperature differential of 135 on the outside and 170 on the inside.

Toe out could cause that without any camber issue.

Look at what @dave2278 said about his camber and toe settings and then his tread temperatures and tread wear in two separate posts. He has the same generation of car, but more spring rate than you, 68.75% more front spring rate. Less spring rate, like your car, should increase the need for negative camber, not decrease it.

Dave2278 runs 0° toe.


PS - I don't know anything, but what luck you have somebody who is running the same generation Mustang and using the exact same tire posting in your thread! And he is not having this issue. I would pay attention to his alignment settings for track and spring rates, as well as any other details he is willing to share.

@dave2278 is running the SC3, different tire. I’ve run that tire without this delamination problem.

My research (which is just AI, so you’re right to question it) is saying my problem is the outer shoulder is too cold, caused by toe out and maybe too much neg camber. When I turn in to a corner, the rubber on the outside is mechanically tearing or shearing because it’s too cold. This is causing a delam problem with the 3R but not other tires I’ve used because the 3R compound needs more heat to get in its operating range of 160-200 degrees F. Solution is zero toe and maybe back off camber to even out temps across the tire and get the outer shoulder temp up.

What do actual experienced human beings think of this? Make sense? It does to me, I think ?

 

[stevbd]

If you move camber you introduce toe out on a modern Mustang chassis. They are front steer cars, as you lean the strut in to give negative camber the spindle pivots on the tie rod link and toes out. The movement is significant and not linear. Easy to get 4-5 mm of toe change. It needs to be checked and set each time you make camber changes. A 40 degree temperature difference inside shoulder to outside indicates scrub as JunkYard Dog mentions. The outer shoulder wear is a feature of the tire as the outer tread compound is softer that the rest for that hybrid track/street designation.

I feel like the outer wear is normal but the delam is not?

 

[Junkyard Dog]

Mine are not the 3R, just regular 3.

I am not running time trials or anything so I opted for the standard. I’ll probably go with the 3R when I start being more competitive, I still have a lot to learn

So much for my reading comprehension.

He did not have any problem when running the same tire as you.

I didn’t have this problem with the SC3.

I will try to gracefully bow out now . . .

 

[stevbd]

Sorry just saw your question about tire wear, yes they wear very evenly. Here are some pics of the fronts right before I replaced them, still have some tread but heat cycled out.

I got this set at the beginning on the season, ran 18 autocross and 8 track days plus about 1500 street miles.

View attachment 112347

View attachment 112348

These 3Rs are faster and really fun but they are more fussy and kind of a pita in terms of setup!