Tire wear question

[thelostotter]

What would cause this issue with the inside rears on 305/30R19 NT01s?

Front
Camber: -3.2
Toe: 0

Rear
Camber: -2.0
Toe: 1/8” in

 

[bnight]

What would cause this issue with the inside rears on 305/30R19 NT01s?

Front
Camber: -3.2
Toe: 0

Rear
Camber: -2.0
Toe: 1/8” in

View attachment 73944

Any curbs you are running over ? However both tires on the inside is a bit strange doesn't looks like setup dependant to be fair.

 

[blacksheep-1]

I would agree, it looks like some physical damage to me as well, but it's odd that it happened to both rears and not the fronts, Maybe spinning the tires over some curbs or stones/rocks/ etc on the track

 

[Bill Pemberton]

Good thoughts above and you may actually have a bit too much camber in the rear, since we often saw the inside edges of various fully independent rear vehicles chewing up some tires when brought into the shop where I used to work. It could be as noted above with the chunks coming out, but also what pressures have you been running?

 

[RES_22]

Top pic reminds me of what my PSC2s looked like after a "reputable" enclosed trailer hauling company transported my car 1200 miles a couple of years ago.

They strapped it down along a metal scalloped ridge on the top floor of a stacker...put symmetric longitudinal grooves into the top 1/16" on the inboard edge of the tires....shredded them.

Where do you park when you come off the track? What does the floor of your trailer look like?

Those symmetric, scallopy, evenly-spaced inboard grooves on the tire in the top pic look to have been made by either something where a tire sat hot, loaded on a mechanical feature....or like @blacksheep-1 said, spinning it up over something on the track...same place every time.

 

[Bill Pemberton]

Hopefully some of the thoughts will get you to the answer as it is more common see something like this one the outside edges. There have been various tires who exhibited a groove of doom on the outside edge from autocross or track use and it is not usually on the inside. Not going to name tires and cause any paranoia since many were taken off the market over the years, no longer in production, improved, or not normal track tires. Agree it looks more like track damage ( rocks, curbs , rough track ) but throwing out the alignment issue only because I have seen that , though on rare occasions.

 

[stevbd]

OP, you're talking about the blistering right? I've seen that a number of times and done it myself. It's not normal wear but it's not totally unusual either, especially as tires wear out. It's due to the internal structure of the tire overheating and coming apart for some reason. Why the tire is overheating in that section is the question, it could be tire pressure, alignment, spring rates, possibly driving style..... A tire pyrometer could be helpful to diagnose if you don't have one already.

More typically I've seen it on the outside edges of tires.

Everyone's comfort zone is different but blistering is a sign the internal structure of the tire is failing for some reason so I wouldn't just ignore it. Personally I have used tires with a small blister or two, watching them carefully, but I wouldn't use those tires you posted.

 

[blacksheep-1]

Blisters should be more uniform, and deeper. I'm pretty sure that's debris. You can see where the tire hit it, imbedded, then smashed itself sideways and cut into the tread, the tire was also spinning when it happened, which is why it was multiplied several times.
If I was to hazard a guess, I'd say the top tire was a RR the bottom a LR

* I did ninja edit there*

 

[thelostotter]

Wow, lots of feedback from everyone, appreciate it!

I was intentionally vague to prevent guiding the conversation a certain way; just to see what people's initial reactions were. The fronts did a similar thing, they just have way more OPR so its harder to tell. I actually think the wear across the tires is very even minus the damage occurring, so that's why I'm confused.

All the track time on these tires were at AMP (Arizona), same curbs as I've hit hundreds of times before. I don't think debris did them in as generally take clean lines since I don't like beating my car up for a fraction of a second in HPDE. Track surface there is kind of rough, I wouldn't say its awful but its not fresh either. I just park on asphalt at the track, and I drive to/from the track since I'm close, no trailering. Never ran over anything on the road that would cause damage, especially to all 4.

I normally run 37 psi front, 36 rear. I noticed these NT01s just never stuck like I thought they should and I saw this wear beginning to start, so I worked down to 34psi front, 32 rear. Car felt better, the wear accelerated and this is what they looked like at the end of my last day. (4 days, 16 sessions on these tires). I don't have a pyrometer, I need to invest in one.

These tires are coming off, I'm not comfortable with them like this. I suspect I may have overheated these on the initial heat cycle despite trying to take it easy. I also suspect control arm deflection from bushings or worn balljoints so I am replacing both front arms with new ones with bearings, and removing the rear lower control arms to put bearings there as well. I will get it aligned with slightly less camber and will be running Goodyear SC3 non-R tires next. Just trying to prevent blowing through tires so quick.

 

[blacksheep-1]

Take a heat gun and scrape the clag off, it will tell you a lot.

 

[Bill Pemberton]

It will be interesting to see what your experience ends up being with the Goodyears. I think what makes it hard to give you a definitive answer is there looks to be definite cuts and damage that appears from debris or curbing as Blacksheep notes and then there are areas that appear as blistering like Stevbd mentions. Both could be correct but the best thing is you are dumping the Nittos and going with new rubber. Whatever the cause I think it is universal from the folks who answered you , those tires need to be parked, trashed and sent to the track tire cemetery!

 

[flyhalf]

What it is weird is damage at the same exact place in both tires. Are you sure 100% you are not rubbing ?
In case of lowered cars I've seen somenthing similar. Reading your second post proposed the same thing i was thinking about what can happen with overheating and over inflated.
Last Do you rotate tires?

 

[thelostotter]

I can't see any witness of rubbing. I do rotate tires between track days, but not between sessions.

I did notice that the circumferential cuts people are commenting on line up with the tread pattern where it cross that rain groove on all 4 tires.

Bill, I was your 5,000th like. You're welcome.

 

[stevbd]

For sure @blacksheep-1 has forgotten more about tires than I will ever know but I can say your tires look almost identical to the blistering I experienced on my Goodyear SC3. Except mine blistered on the outside edge.

Otter, I think you are on to something with the initial heat cycle not being done properly. I never bothered with that and didn't do it on my GY SC3 and got blistering. Is it a cause, I dunno, it's kind of proving a negative but I am going to do the Tirerack heat cycle service this time around. Seems worth a try at $15/tire. Anecdotally all my track rat friends say the initial heat cycle is a real thing and doing it right does make a difference in tire longevity. I remember seeing a very old (like 20+ years) comparison test that showed a marked increase in tire life with a proper initial heat cycle, regardless whether the heat cycle was done on the road or the tirerack service.

Hey, I saw it somewhere on the internet so it must be true lol. I'd be interested what @blacksheep-1 or the other tire gurus on here think about it.

 

[JAJ]

What are the date codes? Could they be old stock?

 

[blacksheep-1]

For sure @blacksheep-1 has forgotten more about tires than I will ever know but I can say your tires look almost identical to the blistering I experienced on my Goodyear SC3. Except mine blistered on the outside edge.

Otter, I think you are on to something with the initial heat cycle not being done properly. I never bothered with that and didn't do it on my GY SC3 and got blistering. Is it a cause, I dunno, it's kind of proving a negative but I am going to do the Tirerack heat cycle service this time around. Seems worth a try at $15/tire. Anecdotally all my track rat friends say the initial heat cycle is a real thing and doing it right does make a difference in tire longevity. I remember seeing a very old (like 20+ years) comparison test that showed a marked increase in tire life with a proper initial heat cycle, regardless whether the heat cycle was done on the road or the tirerack service.

Hey, I saw it somewhere on the internet so it must be true lol. I'd be interested what @blacksheep-1 or the other tire gurus on here think about it.

Oh yes, heat cycling is very important, we must have scuffed at least 10 sets fir the 24 hour.
It's basically like this, the first 4 laps on a tire will be It's fastest ( if proper prep is done) @flyhalf proved that at Daytona with his banzai run.
However, that is not a way to make a tire last. A few years ago we scuffed some tires at Daytona in a real heavy mist/rain.
We used them later in the week for the race, the BMW guy chasing us was on the same compound only stickers. AJ finished the race on blistered tires, the other guy literally blew them off the car just over halfway through.
So to answer your question, stickers will always be faster, but for a shorter period. Scuffs will not stick as well but will last a longer period of time. So I would say yes to the heat cycling, but I'd still scuff them in.

 

[Scootsmcgreggor]

The cuts I have no idea about. The blistering though looks very similar to what we would see drifting when a tire overheated usually because of pressure too high. No idea if there’s any applicability here but it makes me wonder when you say a good chunk of this tire’s life was at 36-37psi. I know some pleople report NT01’s being good at those pressures but mine were awful that high. Much better around 31-32.

 

[Bill Pemberton]

Heat cycling ( by TireRack, etc. ) seems to be beneficial if you can not do it at the track or at home. For many with pure Racecars that can not be driven on the street, having two sets of tires/wheels at the track is not always in the checkbook, so you can not heat cycle one set while running on another. Heat cycling usually recommends letting the tires sit for 24-48 hours but all the Tire Gurus I have known over the years suggest a week or more sitting and curing as the best benefit for the heat cycling. So if time is an issue, or it is going to be hard to heat cycle the tires, then consider having Tire Rack do it.

Keep in mind many 200 TWR tires do not endorse this as necessary , so it is not a situation one does across the board. I used to take my R7s out on the highway when I had a street legal car and I seemed to have good luck with doing my own heat cycling. I always did it weeks before I ran them on track.

Just my experience over about 40+ years.

 

[blacksheep-1]

Just out of curiosity, you weren't running goat pee were you?
I still don't think it's a blister, but I've seen tread come off the carcass when guys tried to get a bit too much life out of them.

 

[thelostotter]

Just out of curiosity, you weren't running goat pee were you?
I still don't think it's a blister, but I've seen tread come off the carcass when guys tried to get a bit too much life out of them.

I was not, should I?