Direzza ZII Chunking?

[TheeGovernor]

how new were the tires? How much tread?

[will.c]

Originally Posted by TheeGovernor

how new were the tires? How much tread?

This was my 4th DE, 8th day on these tires that I bought new. Tread was 5-6/32.

[3002 tii]

Knowing how you drive and what you drive, I have to agree with others. You're overdriving those tires. Not saying you're not smooth but on a stock worn suspension (shocks and bushings) coupled with insufficient camber -- you're asking the tires to do too much.

[Sleeper519]

Originally Posted by 3002 tii

Knowing how you drive and what you drive, I have to agree with others. You're overdriving those tires. Not saying you're not smooth but on a stock worn suspension (shocks and bushings) coupled with insufficient camber -- you're asking the tires to do too much.

OP, I say just drive the snot out that car. Our M3s, tho heavy, are very capable and fun track cars. Yes, the limits of the stock components (brakes, tires, suspension) can be easily exceeded by advanced drivers. i say, don't slow down one bit, just upgrade your equipment to match the rigors of hard track duty. A BBK, camber plates, and R-comps will transform the car and the components will be up for the task. As the driver advances, so must the hardware. Who goes to the track to drive slower anyway??

Just my 0.02.

[3002 tii]

Originally Posted by Sleeper519

OP, I say just drive the snot out that car. Our M3s, tho heavy, are very capable and fun track cars. Yes, the limits of the stock components (brakes, tires, suspension) can be easily exceeded by advanced drivers. i say, don't slow down one bit, just upgrade your equipment to match the rigors of hard track duty. A BBK, camber plates, and R-comps will transform the car and the components will be up for the task. As the driver advances, so must the hardware. Who goes to the track to drive slower anyway??

Just my 0.02.

Camber will definitely help but R-comps on a stock worn suspension will only make the problem worse. If your'e going to spend $1000+ for quality tires, there's no point in overdriving them and being forced to prematurely replace them. I'm not telling OP to drive slower. Similar to your advice I'm telling him to upgrade the hardware but I think suspension/bushings/camber is the more immediate concern, not BBK or R-comps.

[aus]

I've seen instructors fly around a track on stock tires and brakes because they're smooth, which makes them fast and saves the tires.
It's not always equipment that's the issue.

.

[OC3]

That's what my outside front tire (the track was CW config, so the driver's side) looked like when (early in my tracking endeavor) I ran 2 back-to-back extended sessions (11 laps & 14 laps) without first bleeding the tire pressure before the 1st session and not checking tire pressure in-between said 2 sessions.

Somebody was walking by my car in the pit area and pointed out the chuncked tire and, when I checked the pressure, they were at 48 psi (good 10 min's after I came in from the second session). x)

[Sleeper519]

Originally Posted by 3002 tii

Camber will definitely help but R-comps on a stock worn suspension will only make the problem worse. If your'e going to spend $1000+ for quality tires, there's no point in overdriving them and being forced to prematurely replace them. I'm not telling OP to drive slower. Similar to your advice I'm telling him to upgrade the hardware but I think suspension/bushings/camber is the more immediate concern, not BBK or R-comps.

I hear ya, point taken. My previous comments were sincere, but with some added hyperbole and tongue-in-cheek in response to all the "just drive slower" comments.

However, I am driving on a stock suspension (with the exception of camber plates @ -2.6) and R-comps, and I am not tearing up tires at all. As a matter of fact, I think I manage my tire wear better than a lot of my track mates. Conversely, i refuse to track my street tires anymore at all because I can flat out destroy them in a day or two driving with the same setup. Point being is that R-comps will hold up under aggressive driving FAR better than any street performance tire, IMO. I choose to not get coilovers and upgraded bushings because its my DD and I LOVE my street ride with EDC. (Some will say that I can retain comfy street ride with the right coilies but I remain skeptical...).

I do agree that camber plates are a big key for tire management.

The suggestion that he upgrade to a BBK is based on OPs other thread about burning up all manner of pads and getting persistent shimmey with his (inferior) stock brake system. Others will say that he is in some fashion not braking properly. I say that the stock brake system simply isn't cut out for rigorous tracking. I went thru similar travails as he did. I would say the StopTechs are my single most favorite mod for the track.

Cheers.

[will.c]

Taking lots of notes here guys. Thanks all.

I got a bunch of stuff to try next time out:

1) Swap front hats to get ~2.5 neg camber;
2) Try slightly different braking technique per the other thread;
3) Revise brake duct inlet design;
4) Try Hawk pads;
5) Get coilovers; and
6) If I win the lotto; get a BBK.

Will follow up with a report.

[V1.47fan]

Originally Posted by will.c

Taking lots of notes here guys. Thanks all.

I got a bunch of stuff to try next time out:

1) Swap front hats to get ~2.5 neg camber;
2) Try slightly different braking technique per the other thread;
3) Revise brake duct inlet design;
4) Try Hawk pads;
5) Get coilovers; and
6) If I win the lotto; get a BBK.

Will follow up with a report.

Ground Control has adjustable camber plates that work with the stock springs...I dont think swapping the top hats will get you anywhere near -2.5 neg camber on the E9X M3.

[bigjae1976]

Let's keep in mind the OP is driving an E46 which needs a lot more camber with sticky tires.

If I had to guess, its the fast, long right handers and then going over the bumpy curbs on exit. Nothing glaringly wrong with your driving. But you did seem to be understeering quite a bit.

[White 13]

Originally Posted by OC3

That's what my outside front tire (the track was CW config, so the driver's side) looked like when (early in my tracking endeavor) I ran 2 back-to-back extended sessions (11 laps & 14 laps) without first bleeding the tire pressure before the 1st session and not checking tire pressure in-between said 2 sessions.

Somebody was walking by my car in the pit area and pointed out the chuncked tire and, when I checked the pressure, they were at 48 psi (good 10 min's after I came in from the second session). x)

I was thinking a tire with low pressure would flex more, roll over more, build more heat and be more likely to chunk the outside edges. Higher pressure would seem to keep the tire off the edges. I had a set of PSS chunk to the cords while nearly new and I am trying to learn more.

Original set of Continentals had some small chunking in the center towards the end of their life. I am thinking maybe a little wheel spin and maybe too much pressure.

What hot pressure do you now shoot for?

Thanks.

[OC3]

Originally Posted by Sleeper519

I hear ya, point taken. My previous comments were sincere, but with some added hyperbole and tongue-in-cheek in response to all the "just drive slower" comments.

However, I am driving on a stock suspension (with the exception of camber plates @ -2.6) and R-comps, and I am not tearing up tires at all. As a matter of fact, I think I manage my tire wear better than a lot of my track mates. Conversely, i refuse to track my street tires anymore at all because I can flat out destroy them in a day or two driving with the same setup. Point being is that R-comps will hold up under aggressive driving FAR better than any street performance tire, IMO. I choose to not get coilovers and upgraded bushings because its my DD and I LOVE my street ride with EDC. (Some will say that I can retain comfy street ride with the right coilies but I remain skeptical...).

I do agree that camber plates are a big key for tire management.

The suggestion that he upgrade to a BBK is based on OPs other thread about burning up all manner of pads and getting persistent shimmey with his (inferior) stock brake system. Others will say that he is in some fashion not braking properly. I say that the stock brake system simply isn't cut out for rigorous tracking. I went thru similar travails as he did. I would say the StopTechs are my single most favorite mod for the track.

Cheers.

JRZ RS Pro on street settings (for me, 3 clicks from softest) is far more comfortable than stock suspension. Far more. It's been confirmed by 4 E9x M3's here in SoCal, including mine.

How much more supple and superb it is over stock/EDC was immediately noticeable when I went from stock to JRZ on my 2011 E90 M3. Then, a couple of years later, I traded it in for a 2013 E92 M3 and was stock while the car was being broken in and I hated the stock/EDC ride on the streets after being used to JRZ. Couldn't wait to get the JRZ on the car.

Originally Posted by White 13

I was thinking a tire with low pressure would flex more, roll over more, build more heat and be more likely to chunk the outside edges. Higher pressure would seem to keep the tire off the edges. I had a set of PSS chunk to the cords while nearly new and I am trying to learn more.

Original set of Continentals had some small chunking in the center towards the end of their life. I am thinking maybe a little wheel spin and maybe too much pressure.

What hot pressure do you now shoot for?

Thanks.

31 psi hot during summer months & 32~33 psi in winter months. On R-comp's (NT01 & TD).

Been tracking only 40 months so far and I progressed from PS/2 to PSS to AD08 to R-S3 to NT01 and TD. Seems like eons ago when I last tracked street tires...

Yes, generally "tire with low pressure would flex more, roll over more," but the flip side is, the lower the pressure the more the tire's gonna sag and thereby you wind up with more rubber contact patch area. Anyhow, the trick is to set it low as possible without the sidewalls rolling over. At 31 psi hot on R-comp's, many of us find that if you run'em hot enough (i.e. at certain pace), it's just the right pressure. On the sidewalls of NT01, there are these triangle marks and you want the scruff marks to come just to the up-pointed tip of said triangles.

Edit: as for street tires, I'd suggest 34 to 37 psi hot.

[White 13]

OC3,

Thanks for the help.

[CSBM5]

As to the over driving comments...

Picture the lateral force versus slip angle plot for your tires. For a given loading (which changes constantly of course), there is a slip angle that gives maximum lateral force. Your goal is to stay to the left of that peak. You'll generate the same grip as you will sitting just over the peak on the right side of it, but then you'll have a higher slip angle and be generating more heat input into the tires, etc. In addition, if you're already over the peak, you have nothing left in reserve for mid-corner corrections, etc.

In this pic (now a link) below, if you draw a line across the graph at 3500lb, you can generate that level of grip at 7° of slip angle and at about 9° of slip angle. If you're at 9°, all you're doing is creating excessive heat and wear on the tires while also leaving no reserve grip available.

EDIT: I have now provided a link to a site I found online with a graph so that they're aren't any potential copyright issues with the previous graph.

Hope that helps a bit, not necessarily saying this is your issue, but it can't hurt to point out how many people unnecessarily destroy tires on the track.

http://www.circletrack.com/ultimater.../photo_05.html

[will.c]

Originally Posted by bigjae1976

If I had to guess, its the fast, long right handers and then going over the bumpy curbs on exit. Nothing glaringly wrong with your driving. But you did seem to be understeering quite a bit.

There's one long 3rd gear reducing-radius right hander that leads to a very tight off camber right before which a lot of braking is required. I think this is probably the major culprit.

Originally Posted by OC3

Yes, generally "tire with low pressure would flex more, roll over more," but the flip side is, the lower the pressure the more the tire's gonna sag and thereby you wind up with more rubber contact patch area. Anyhow, the trick is to set it low as possible without the sidewalls rolling over. At 31 psi hot on R-comp's, many of us find that if you run'em hot enough (i.e. at certain pace), it's just the right pressure. On the sidewalls of NT01, there are these triangle marks and you want the scruff marks to come just to the up-pointed tip of said triangles.

Edit: as for street tires, I'd suggest 34 to 37 psi hot.

Ah, that's right. I'll remember this one next time and actually try the lowest possible without destroying the triangle.

Originally Posted by CSBM5

As to the over driving comments...

Picture the lateral force versus slip angle plot for your tires. For a given loading (which changes constantly of course), there is a slip angle that gives maximum lateral force. Your goal is to stay to the left of that peak. You'll generate the same grip as you will sitting just over the peak on the right side of it, but then you'll have a higher slip angle and be generating more heat input into the tires, etc. In addition, if you're already over the peak, you have nothing left in reserve for mid-corner corrections, etc.

In this pic (now a link) below, if you draw a line across the graph at 3500lb, you can generate that level of grip at 7° of slip angle and at about 9° of slip angle. If you're at 9°, all you're doing is creating excessive heat and wear on the tires while also leaving no reserve grip available.

EDIT: I have now provided a link to a site I found online with a graph so that they're aren't any potential copyright issues with the previous graph.

Hope that helps a bit, not necessarily saying this is your issue, but it can't hurt to point out how many people unnecessarily destroy tires on the track.

http://www.circletrack.com/ultimater.../photo_05.html

Thanks for the comments and the link. Maintaining a certain slip angle seems beyond my skill level yet. I have felt it though. I was riding in an instructor's 981S with NT01s and he seemed to whip the car around for some turns, and the car seemed to be going around the turns at a slight drift angle, but no tire noise and it felt really really stable and planted. I was pretty shocked at the difference in grip level too.

There's also a mention on what affects the amount of weight transfer, and it covered some very interesting points.

[Richbot]

E46's want 3+ degrees that's pretty classic lack of camber wear pattern. Especially with the soft stock suspension it's going to eat outside front edges without more camber. The E46 front suspension loses a ton of camber in bump

Also agree you can drive around this to a certain extent, but not going to get around it entirely. Some great drivers have tried making the E46 work on stock suspension over the years, and the others with similar front strut desgin, and all of them punish their outside front edges unmercifully in corners without stiffer setups and camber

Also agree you need to up the tire pressures to keep it off the sidewall. The other quick and dirty fix besides camber for this is a stiffer front swaybar

[will.c]

Just rotated my front hats (mind you this is E46).

Camber went from -1.5 to about -4.8.
Toe went from 1/8" in to 0.

Went for a quick ride and it felt pretty stable actually in both turning and braking hard, contrary to my expectation of darty or jumpiness.

I got a DE tomorrow at NJMP Lightning. I'll report back with tire wear updates.

I also flipped the tires to use the other fresh half.

[will.c]

Update:

-5 front camber w/ 0 front toe made my car very very VERY twitchy. Steering felt to have become quicker, front grip was endless compared to rears, the car felt far from neutral. The slightest steering input or lift or tapping the brake would immediately induce snap oversteer. Just like what they say for a GT3, I had to gas way before apex to just settle the rear, then gas, gas, and more gas.

Scared the shit out of me at first, but I think I eventually got to enjoy it, and now I think I like this a little more than before, which, I now realize, was just understeer everywhere. I just need a little less camber in the front and a little more in the back w/ maybe 255/275 stagger.

I can see how a well developed driver can benefit from an oversteery car, but my current skills are not precise enough to take advantage of it. (Or maybe it was just a little too twitchy.) All in all I was wasting too much time sliding, thus I could not beat my old PR from when I used to under-drive by half a sec.

Videos:

[will.c]

Tire wear:

No more major chunking like last time, but following were still observed:

1) Rough surface on the outside edges of the front tires. I think this is because these areas were not touching the ground on my way back home due to hugh neg camber.

2) Small cracks still formed on the front tires.

3) Front left tire outside tread blocks were all cracking off the tire core - all the way around.

4) Blue strips formed on the outside edges of the front tires.

5) Rear right tire started to splice a little. Maybe the left-hand slides caused it.

[OC3]

Originally Posted by will.c

I just got a few videos uploaded. Sorry for the crappy audio quality, but I'd appreciate any input if there are things I can do to manage the tires. I don't think I felt a lot of pushing... rather I was trying to trail brake quite a bit, and spent more time on catching the rear end wanting to come out (maybe b/c of square setup), but anyways... any criticism is welcome.

Originally Posted by will.c

Update:

-5 front camber w/ 0 front toe made my car very very VERY twitchy. Steering felt to have become quicker, front grip was endless compared to rears, the car felt far from neutral. The slightest steering input or lift or tapping the brake would immediately induce snap oversteer. Just like what they say for a GT3, I had to gas way before apex to just settle the rear, then gas, gas, and more gas.

Scared the shit out of me at first, but I think I eventually got to enjoy it, and now I think I like this a little more than before, which, I now realize, was just understeer everywhere. I just need a little less camber in the front and a little more in the back w/ maybe 255/275 stagger.

I can see how a well developed driver can benefit from an oversteery car, but my current skills are not precise enough to take advantage of it. (Or maybe it was just a little too twitchy.) All in all I was wasting too much time sliding, thus I could not beat my old PR from when I used to under-drive by half a sec.

Videos:

Nice driving. Quick hands too! Enjoyed watching your videos.

[will.c]

Originally Posted by OC3

Nice driving. Quick hands too! Enjoyed watching your videos.

Haha thanks. I'm new to this over-driving and still learning. Hopefully I'll find some time to compose a fun video to join the "oh sh!t" crew