Avoiding chunking/tire damage while tracking

[dfwatt]

Agreed. If you’re tracking a 4000lb car be prepared to spend money on tires. Don’t waste your money on RE71Rs though unless you’re actually a good driver competing for trophies. Get the R-S4s.

But does it have the predictability at the limit of the re71?. I'm not too worried about the cost or I should say that the costs are obscene anyway so an extra few hundred what the heck! Don't the inexperienced drivers want the most predictable tire at the limit with the best feedback that they can afford? It's been years since I owned a pair of re71s - I didn't really enjoy them on the street very much but one of the things I remember about them was just how well they communicated. It was relatively easy to keep them at nine tenths, and you knew when you were getting to 10/tenths

 

[Nocturnal]

Negative camber should help, but not super easy to adjust that without lowering your car or spending money on adjustable arms. 45 PSI hot seems a bit high, especially with AutoX since it really doesn't put that much heat into the tire due to the short laps.

Honestly i think a lot of the chunking that people are experiencing is simpy due to this car being a heavy, powerful beast that puts more load into the tires than almost anything else out there. Most of the reports i've seen are during AutoX usage, which makes sense as the tires are likely starting relatively cold and then getting the absolute piss beat out of them for ~1 minute straight, multiple times over and over.

Your best bet to prolong those specific tires is less aggressive driving (reduced slip angle) and/or trying to get them hot before each lap if you can. The RE71R is definitely going to be a better AutoX tire, but it's loud and harsh for daily driving (sticky = gravel trap) as i've been running them for the last 4 months. It's perfect as a dedicated tire though.

Autox generally involves much tighter curves compared to road course tracks right? My stock tires went through 2 track days on a full course and I didn't see these issues.

Unplugged has some sweet control arms to help with that, i have the prototype set and aligning them was pretty straightforward. It lets you adjust camber and caster as the car comes with slightly uneven caster from the factory (road crown reasons).

They aren't quite for sale just yet, but i'm sure they are coming soon and you could email UP to get them early.

Unplugged Performance Adjustable Front Upper Control Arms for Model 3

I have zero experience with suspension components (former cars were all pure street cars with some mild drag racing). Do people adjust those just once or is that something you adjust for each track and then back to "normal" for the street?

 

[Daniel in SD]

Wife isn't going to like that lol. Still trying to figure out what to do with my 18s and mxm4. Probably end up tracking whatever i have since I'll new to it anyways.

Will the AS mxm4s hold up better?

MXM4s will disintegrate. I recall seeing some pictures on this forum.
I think there are pictures on the forum of how well PS4S hold up to a track day.

But does it have the predictability at the limit of the re71?. I'm not too worried about the cost or I should say that the costs are obscene anyway so an extra few hundred what the heck! Don't the inexperienced drivers want the most predictable tire at the limit with the best feedback that they can afford? It's been years since I owned a pair of re71s - I didn't really enjoy them on the street very much but one of the things I remember about them was just how well they communicated. It was relatively easy to keep them at nine tenths, and you knew when you were getting to 10/tenths

They seem fine to me (I've only driven them on a RX-8 at autocross so YMMV). I know they're super popular with the Miata crowd and for endurance racing. I've ordered a set for Exocet kit car but they've been backordered for months.

 

[SammichLover]

Will the AS mxm4s hold up better?

No.

Someone here has pics after doing this. They looked exactly like mozzarella that had been run over a large slot grater, then tossed in the freezer as there was this hoarfrost looking bits of rubber flayings sticking off the edges of the contact surfaces.

I only ran them AX and they smelt of death after a couple runs. That ain't a good thing, especially considering it was a relatively cool day I did this.

 

[stickman]

I almost do want to know how!

Hm interesting that you got that much roll at 39 PSI. I run my PS4s on the street around 40-42 PSI and don't have that much issue.

I was planning on putting the RE71Rs at 35PSI cold to start, maybe should have it higher? The sidewall on the RE71Rs is very little

Well street hot is very different than track hot. My first day on the P4S they gained 7-9psi iirc from street hot to right off the track hot (when you should measure pressures- like as soon as possible after you pull in). And unless you’re driving like a total maniac you’re not putting anywhere near the lateral force on the tires on the street that you do on the track

I would start the RE-71rs at like 40 cold and check your pressures, and roll (they have a handy triangle indicator on the sidewalk) I think I settled on 42 hot and they were great. Excellent grip, even wear. They’re super confidence inspiring. When they start to slide it’s like “oh hey they slid a little there, cool”

 

[afadeev]

]Honestly i think a lot of the chunking that people are experiencing is simpy due to this car being a heavy, powerful beast that puts more load into the tires than almost anything else out there.

Heavy and relatively under-tired car (235mm wide rubbers under 4K lbs vehicle is far too narrow) are all valid consideration.
But the biggest impact, by far, is the fact that Michelin has been mixing multiple compounds into their 4S and Super Sport tires. The outer shoulder is of much softer rubber, which works great on the street by providing additional bite during turns and under braking. However, that softer rubber overheats and falls off in chunks on track and at autoX. Especially during high speed turns.

BTDT with my ///M3 and Pilot SS's the first time I took it to a DE. Lesson learned.

I have zero experience with suspension components (former cars were all pure street cars with some mild drag racing). Do people adjust those just once or is that something you adjust for each track and then back to "normal" for the street?

Once you change geometry of one suspension element (strut length, control arm length, camber/cast), it always effects other measurements. The most obvious and hardest hitting on the tire lifespan is the toe.
Basically, you set the car up for track (or a compromise between track and street), then align it to set desired toe (usually 0 for track, out for autoX, in for street), and live with the setup.

If you know how to, and have the tools to align the car yourself - great.
If not, a quality alignment shop will charge you $120-200 for four wheel alignment.

a

 

[dfwatt]

Heavy and relatively under-tired car (235mm wide rubbers under 4K lbs vehicle is far too narrow) are all valid consideration.
But the biggest impact, by far, is the fact that Michelin has been mixing multiple compounds into their 4S and Super Sport tires. The outer shoulder is of much softer rubber, which works great on the street by providing additional bite during turns and under braking. However, that softer rubber overheats and falls off in chunks on track and at autoX. Especially during high speed turns.

BTDT with my ///M3 and Pilot SS's the first time I took it to a DE. Lesson learned.

Once you change geometry of one suspension element (strut length, control arm length, camber/cast), it always effects other measurements. The most obvious and hardest hitting on the tire lifespan is the toe.
Basically, you set the car up for track (or a compromise between track and street), then align it to set desired toe (usually 0 for track, out for autoX, in for street), and live with the setup.

If you know how to, and have the tools to align the car yourself - great.
If not, a quality alignment shop will charge you $120-200 for four wheel alignment.

a

Much of what you say I agree with but the common complaint or concern with the 235/35 being not enough tire (which of course it isn't from a track standpoint, even aside from its well documented heat vulnerability) has to be mitigated a bit by the fact that it actually has more tread than any 245/35-20 and roughly the same tread width as an average of the three different 255/35 PS4S tires. Tesla didn't do this for no good reason, and people often assume that the only thing unique about the Tesla specific 4S is the acoustic foam - just not true from even a casual inspection of the 4S tire page at Tire Rack.

I suspect that Tesla asked Michelin for more/max possible tread to mitigate the 'undertired' status while keeping rolling resistance from running away too far from their targets (as this is somewhat more a function of section width/compliance than tread width although both are relevant). As your post implies, that probably meant extending the softer outer edge rubber while keeping the section width, and therefore the size rating, the same. I've wondered if this strategy works on the street in terms of giving the car just a bit more lateral (and braking) grip, but makes the tire even more vulnerable to chunking (slightly more softer rubber at the edge), and as several have documented, a lot of roll over unless you keep pressures up (in which case it's pretty greasy, as I have found out the hard way myself).

In any case, I think the consensus is that its a great (if not the best) street tire, long tread life, great ride, reasonably quiet, good dry and great wet traction, good steering feel, etc. Just not a comp tire. Then again, what could possibly be that good at such conflicting functions?

 

[dfwatt]

Much of what you say I agree with but the common complaint or concern with the 235/35 being not enough tire (which of course it isn't from a track standpoint, even aside from its well documented heat vulnerability) has to be mitigated a bit by the fact that it actually has more tread than any 245/35-20 and roughly the same tread width as an average of the three different 255/35 PS4S tires. Tesla didn't do this for no good reason, and people often assume that the only thing unique about the Tesla specific 4S is the acoustic foam - just not true from even a casual inspection of the 4S tire page at Tire Rack.

I suspect that Tesla asked Michelin for more/max possible tread to mitigate the 'undertired' status while keeping rolling resistance from running away too far from their targets (as this is somewhat more a function of section width/compliance than tread width although both are relevant). As your post implies, that probably meant extending the softer outer edge rubber while keeping the section width, and therefore the size rating, the same. I've wondered if this strategy works on the street in terms of giving the car just a bit more lateral (and braking) grip, but makes the tire even more vulnerable to chunking (slightly more softer rubber at the edge), and as several have documented, a lot of roll over unless you keep pressures up (in which case it's pretty greasy, as I have found out the hard way myself).

In any case, I think the consensus is that its a great (if not the best) street tire, long tread life, great ride, reasonably quiet, good dry and great wet traction, good steering feel, etc. Just not a comp tire. Then again, what could possibly be that good at such conflicting functions?

I forgot to mention that the tire's apparent vulnerability to roll over particularly as you drop the pressure into the 30s is probably a direct result of trying to get a highly compliant sidewall that will help reduce rolling resistance (and obviously helps with ride as these tires ride significantly better than their predecessor the Super Sports). Another example of conflicting design parameters. Low rolling-resistance tires have to have very compliant sidewalls and treads. Obviously there are tires with lower rolling resistance than the 4S but in its performance class it's pretty good on that point. I suspect that's why it rolls over badly as documented by Stickman earlier I think in this thread.

 

[Lunares]

Report from first weekend of autcross:

Started the day around 38 PSI in all the wheels. Looked for rollover (my sidewalls are SMALL, 265-35-18). After a few laps we bled the fronts down to 37 idle (not cold, but not on the course). In the course fronts were getting up to around 40.

Rears were at about 40 idle, 42ish in the course.

Overall I'm not sure I'll go much below 35 on the fronts (cold). The car definitely pushes those things on the edge, and the edges already get beat to *sugar* due to the really rough gravel of this parking lot.

I'm wondering what the aspect ratio / sidewall was of the track people who were at around 30 cold.

 

[dfwatt]

Report from first weekend of autcross:

Started the day around 38 PSI in all the wheels. Looked for rollover (my sidewalls are SMALL, 265-35-18). After a few laps we bled the fronts down to 37 idle (not cold, but not on the course). In the course fronts were getting up to around 40.

Rears were at about 40 idle, 42ish in the course.

Overall I'm not sure I'll go much below 35 on the fronts (cold). The car definitely pushes those things on the edge, and the edges already get beat to *sugar* due to the really rough gravel of this parking lot.

I'm wondering what the aspect ratio / sidewall was of the track people who were at around 30 cold.

Curious what tires you were using?

 

[jyalpert]

The MXM4 is a hot pile of garbage for performance driving. It's a tire designed for efficiency. It comes on the Prius, and when they put it on the BRZ, people referred to the car as a drift machine because the tires were so bad.

I use the Nitto NT01 on track. Good grip, good predictability, and amazing wear. It's a similar compound as the legendary Toyo RA-1 but with better carcass and tread design. I've got near 20 track days on this set and they've only slightly fallen off. Less ultimate grip than say a RE71, but better characteristics in other ways (wear, heat management).

If I were doing a lower-heat event like AX, I'd probably get a RE71, Rival S, or RS4. My understanding is that on track those Super 200 tires tend to get greasy after some laps and wear quickly. Maybe more of a TT and AX tire.

I'd also be interested to see a temp profile across the tire after a session on track for the Model 3 on stock suspension. That will tell you all you need to know about camber on this car. (I use a $9 laser thermometer as I'm way too cheap for a pyrometer).

Elephant Racing • Reading Tire Temperature: Road map to suspension tuning

 

[Lunares]

Curious what tires you were using?

265-35-18 RE71R

 

[Lunares]

The MXM4 is a hot pile of garbage for performance driving. It's a tire designed for efficiency. It comes on the Prius, and when they put it on the BRZ, people referred to the car as a drift machine because the tires were so bad.

I use the Nitto NT01 on track. Good grip, good predictability, and amazing wear. It's a similar compound as the legendary Toyo RA-1 but with better carcass and tread design. I've got near 20 track days on this set and they've only slightly fallen off. Less ultimate grip than say a RE71, but better characteristics in other ways (wear, heat management).

If I were doing a lower-heat event like AX, I'd probably get a RE71, Rival S, or RS4. My understanding is that on track those Super 200 tires tend to get greasy after some laps and wear quickly. Maybe more of a TT and AX tire.

I'd also be interested to see a temp profile across the tire after a session on track for the Model 3 on stock suspension. That will tell you all you need to know about camber on this car. (I use a $9 laser thermometer as I'm way too cheap for a pyrometer).

Elephant Racing • Reading Tire Temperature: Road map to suspension tuning

Any recommendations for AX and something not as high performance?

I've gotten the tip to practice AX on a lower performing tire as it will make it easier for me to learn how to manage grip

 

[jyalpert]

Any recommendations for AX and something not as high performance?

I've gotten the tip to practice AX on a lower performing tire as it will make it easier for me to learn how to manage grip

Usually I'd say you should just destroy your all seasons first. But really you might want to upgrade to a decent tire that is a bit stickier but still predictable if the stock Michelins chunk immediately. I'd probably go BFG Sport Comp 2 or the Firestone Firehawk. I hear excellent things about both.

I ran a set of Kumho Ecsta all seasons for my first 4 track days (came on my car when I bought it). Really great for learning - I could practice throttle steering at non scary speeds. Now my daily tire is Bridgestone S04, which is a great rainy track tire as well but not that great in the dry.

 

[Lunares]

Usually I'd say you should just destroy your all seasons first. But really you might want to upgrade to a decent tire that is a bit stickier but still predictable if the stock Michelins chunk immediately. I'd probably go BFG Sport Comp 2 or the Firestone Firehawk. I hear excellent things about both.

I ran a set of Kumho Ecsta all seasons for my first 4 track days (came on my car when I bought it). Really great for learning - I could practice throttle steering at non scary speeds. Now my daily tire is Bridgestone S04, which is a great rainy track tire as well but not that great in the dry.

Yea, I'm already on my 2nd set of pilot sport 4s (I do love them for daily driving), because I chunked both fronts in a single autocross weekend. Hence why I now have a custom set of lightweight 18" rims and RE71Rs. But it seem like those will only last me 4-5 events or so. Hoping to switch to something that will last a year (8ish events)

 

[MoreAgain]

I now have a custom set of lightweight 18" rims and RE71Rs. But it seem like those will only last me 4-5 events or so. Hoping to switch to something that will last a year (8ish events)

I've been very happy with the Federal RS-RR. I have two track days on them and they are holding up well. They are loud as hell, but hard to beat for the price. ($540 a set for 255/35 19)

 

[TexasTeslaRacing]

Finished installing MPP sport coilovers yesterday and did a weight, balance and alinement. Posting for everyone to see the car is almost perfectly balanced front/rear and left/right. Sourcing end links so I can fine tune. Weight includes a 190lbs driver.

 

[Lunares]

Finished installing MPP sport coilovers yesterday and did a weight, balance and alinement. Posting for everyone to see the car is almost perfectly balanced front/rear and left/right. Sourcing end links so I can fine tune. Weight includes a 190lbs driver.

Do those coilovers let you go more negative camber? I'm hoping to get to -2.5 or even -3 degrees

 

[TexasTeslaRacing]

Do those coilovers let you go more negative camber? I'm hoping to get to -2.5 or even -3 degrees

Yes with a 1.25” drop we dialed in -1.27 front and -1.49 rear. Here’s my specs. This is not an aggressive setup as I will get an alinement before track days. Good balance between handling and tire wear.

 

[jyalpert]

Yea, I'm already on my 2nd set of pilot sport 4s (I do love them for daily driving), because I chunked both fronts in a single autocross weekend. Hence why I now have a custom set of lightweight 18" rims and RE71Rs. But it seem like those will only last me 4-5 events or so. Hoping to switch to something that will last a year (8ish events)

NT01 would be an excellent choice here. You'll see them recommended on many other sports car forums as well.

But do not run them in the rain!