Tire Wear: Autocrossed Michelin PSS

[Bimmer-Bob]

The pictures below are of my two front tires: Michelin Pilot Super Sports with ~13,000 miles on them. They've seen 3 track days, and stood up pretty well (I'm a novice driver and so wasn't pushing them too hard). I've recently done a couple of autocrosses, 11-12 runs each time, and noticed chunks of tire missing (from the fronts only) today. Is this normal? I know autocross is pretty rough on the fronts, and that the tires never really come up to temp, but I'm still a little surprised to this. Can I continue to run events like this? Is it even safe to drive on the street?

Incidentally, what pressures are folks using with this set up (225/255, btw)? I started at 37.5 cold, all around.

I think I'm switching to the new Dunlop Direzza's after this. I used to run Star Specs, and they were loud and wore quickly, but at least they wore evenly and grip was great.

[int2str]

Those tires look pretty shot. Not for the chunking actually, but the right shoulder in the top picture looks completely worn. Is that the outside or the inside?

I think it's time for new tires. And if that's the outside of the tire, I'd suggest camber plates next

PS: Did you attend the SDBMWCCA run-off? And was I your instructor?

[Teemo Panda]

Holy shit, that's one heck of a worn out tire!

It's a good idea to replacement with a good set of tires for maximum traction~

[Bimmer-Bob]

Originally Posted by int2str

Those tires look pretty shot. Not for the chunking actually, but the right shoulder in the top picture looks completely worn. Is that the outside or the inside?

I think it's time for new tires. And if that's the outside of the tire, I'd suggest camber plates next

PS: Did you attend the SDBMWCCA run-off? And was I your instructor?

Yes, I did attend that Auto-X, and I think you were my instructor. Howdy!

Anyway, it's kind of confusing, because one of the pictures was taken from the front and the other from behind, but on both of them the outside edge of the tire is on the left of the frame. I'm currently running -1.8° with Dinan camber plates, and will eventually add the M3 control arms for an extra -0.75.

So the chunking isn't that big of a problem? Or just not as bad as the edge wear? I'm not really sure what to do about this - long term, I was planning on switching to a lightweight 17" wheel and go with a square tire setup, and I hate to spend money on new tires for the 18" wheels at this point. On the other hand, I'm not quite ready to spring for the extra expense of wheels at this point...

[Suds]

Originally Posted by Bimmer-Bob

So the chunking isn't that big of a problem? Or just not as bad as the edge wear?

What is the manufacture date code on your tires, that almost looks like an age problem. I always see my severe wear in the outside corners from auto-x.

I do have the Dunlop ZIIs, they do have nice grip, but are noisy on the freeway.

[blutattoo]

I had the same issue with the PSS's. Switched to a different tire and I haven't had the issue happen again. They didn't like autox at all. The outer edges of the fronts wore really quickly. I may have over driven them slightly, but since I changed to the RE-11's no issues. I've heard good things about the Direzza's too.

[Ginger_Extract]

autox on rough concrete/pavement will do that, they are fine to drive on.

[Hops128i]

Originally Posted by Ginger_Extract

autox on rough concrete/pavement will do that, they are fine to drive on.

I was just going to say the same thing. There's a autocross course I now avoid that caused a similar wear, (but not as extreme as the OP). The surface was very hard and coarse. I got this kind of wear pattern on the oem run-craps, and toyo t1 sport tires.

[bimmer Don]

That's normal on auto x if its a rough parking lot. You tires are fine. Just keep a eye on the outside edge

[Kgolf31]

The tires suck. And now you finally realize that all of the hype on PSS tires flies right out the window when you actually push the tires.

Get ZIIs, RS3s or Rivals and this will never happen again.

Here are my RS3s on a slightly camber challenged Z4M with around 10 autocrosses and 1 track weekend. Just flipped the tires to get more even wear. Conditions varied from smooth asphalt to coarse airport concrete.

[jafo1701]

I wouldn't say the tire's suck as the previous post. They are a Max performance tire with a 300 treadwear rating. No way they can perform like the Rivals, Dirzerras or RE 11As which are in the extreme performance category with 200 treadwear rating. I think they are geared more for the spirited street driver that does occasional HPDE or auto X. I had them on my E36 M3 as my street/Auto X tires, ran star specs for the track. I was extremely competitive with them in STU in AutoX with my M3 with the PSS. Of course when I wrecked the M3, I moved my PSS with LTW5 wheels over to my 135i as my track/Auto X wheels. Sold my Kosei/star spec set up when I parted out the car. I can say that as soon as they wear out, I'll be replacing them with the Rivals though.

[Bimmer-Bob]

Originally Posted by bimmer Don

That's normal on auto x if its a rough parking lot. You tires are fine. Just keep a eye on the outside edge

Thanks! That's kind of what I was hoping. I will keep an eye on these & replace with ZII's when the time comes. Just wanted to make sure it wasn't an emergency.

[Kgolf31]

Originally Posted by jafo1701

I wouldn't say the tire's suck as the previous post. They are a Max performance tire with a 300 treadwear rating. No way they can perform like the Rivals, Dirzerras or RE 11As which are in the extreme performance category with 200 treadwear rating. I think they are geared more for the spirited street driver that does occasional HPDE or auto X. I had them on my E36 M3 as my street/Auto X tires, ran star specs for the track. I was extremely competitive with them in STU in AutoX with my M3 with the PSS. Of course when I wrecked the M3, I moved my PSS with LTW5 wheels over to my 135i as my track/Auto X wheels. Sold my Kosei/star spec set up when I parted out the car. I can say that as soon as they wear out, I'll be replacing them with the Rivals though.

The PSS are a good tire for DDing. When it comes time to get pushed to the limit...they give up and start shredding.

There is another guy on this forum who had fresh PSS tires and did a track day and ruined them the same way.

They are not meant to be autocrossed.

Walk around Paddock and Grid next time you're at an autocross or track event and I can almost guarantee people aren't running PSS out of their own choice. Either the car came with those tires, or they can't afford new ones yet, or are newbies


As well, no offense, E36Ms aren't too good in STU. If there was any decently prep'ed Evo or STi you'd be loosing pretty quickly.

OP - A tire degrading like that IS NOT NORMAL just because you autocrossed. Just FYI

[MadMan77]

The person mentioned above whose tires fell apart was not AutoXing. He was running fast laps on a track with cold tires which he admits to.

As stated above the PSS is not an extreme performance tire and should not be compared to them.

[jafo1701]

Originally Posted by Kgolf31

The PSS are a good tire for DDing. When it comes time to get pushed to the limit...they give up and start shredding.

There is another guy on this forum who had fresh PSS tires and did a track day and ruined them the same way.

They are not meant to be autocrossed.

Walk around Paddock and Grid next time you're at an autocross or track event and I can almost guarantee people aren't running PSS out of their own choice. Either the car came with those tires, or they can't afford new ones yet, or are newbies


As well, no offense, E36Ms aren't too good in STU. If there was any decently prep'ed Evo or STi you'd be loosing pretty quickly.

OP - A tire degrading like that IS NOT NORMAL just because you autocrossed. Just FYI

I was just sick of swapping out to my track wheels on every autocross event so decided to stick with the PSS, which as I mentioned were my street tires for my M3. I initially just tried them out to test how they would do for Auto X, and they surprisingly did well. So I just stuck with them for Auto X events. I'm sure my times would be a bit faster with my Star Specs, but at least for me not worth the hassle of transporting and swapping out wheels just for an Auto X. As for being competitive, well I'm in Iowa, so probably don't have the competition as in some of your more populated area. That being said I would consistently be in the top ten. We average 40 to 60 cars per autocross event. Since this is my first year tracking and auto X with my 135i I decided not yet to upgrade tires from my PSS.

There are plenty of people out there who are running on mostly stock cars, no track pads etc. They do a few auto Xs and track days per year and don't really push their cars. They want a tire with good tread life and performance. I think for those the PSSs are fine in that case. Obviously not the choice for the enthusiast or someone who really wants to push their car.

[Bimmer-Bob]

Originally Posted by MadMan77

As stated above the PSS is not an extreme performance tire and should not be compared to them.

That's true, but there are plenty of guys on these boards that adamantly insist that Michelin PSS's are the best passenger tire ever made and that every other "no-name" tire (Dunlop?) is inferior. IMO any tire that is marketed as a performance tire (weather extreme, ultra, max, whatever) ought to be able to hold up to an autocross for god's sake.

[bimmer Don]

E36 are great in stu the national champ in stu is a e36 m3

[Oni_]

To be honest looking at those pictures, I don't think it's an issue of the tire. Usually chunking occurs when the tire is pushed beyond its limits and starts to slide. That's normally an indication of overdriving the car. For example, if you have understeer and are continually adding more steering input or throttle, the tire cannot provide further grip. The tire begins to slide, and thus your rubber starts chunking (think like a cheese grater). When people change the tire to a more aggressive tread / compound, the grip level increases. The grip level can often mask the driving technique (that's why you'll see most people do not suggest learning to drive on R-comps).

When I first started autocrossing, I had a tendency to overdrive the car, and that's when I saw my tread chunking. Once I gained more experience, instruction, etc., changing my driving style made the difference. I've never seen chunking on my tires since on the various vehicles I've owned and tracked. My wife's SLK55 had Michelin PSS tires upfront, and I never had issues with chunking on the track.

[CSBM5]

Originally Posted by Oni_

To be honest looking at those pictures, I don't think it's an issue of the tire. Usually chunking occurs when the tire is pushed beyond its limits and starts to slide. That's normally an indication of overdriving the car. For example, if you have understeer and are continually adding more steering input or throttle, the tire cannot provide further grip. The tire begins to slide, and thus your rubber starts chunking (think like a cheese grater). When people change the tire to a more aggressive tread / compound, the grip level increases. The grip level can often mask the driving technique (that's why you'll see most people do not suggest learning to drive on R-comps).

When I first started autocrossing, I had a tendency to overdrive the car, and that's when I saw my tread chunking. Once I gained more experience, instruction, etc., changing my driving style made the difference. I've never seen chunking on my tires since on the various vehicles I've owned and tracked. My wife's SLK55 had Michelin PSS tires upfront, and I never had issues with chunking on the track.

That was my impression too. They look like they have been run over-inflated and also over-driven at too high slip angles.

OP, keep your hot pressures at ~38psi, and don't over-drive the fronts. Think of the slip angle vs tractive force curve -- you can get the same grip being just to the left of the peak as you can being just over it and to the right. The later results in *much* more tire wear for no gain -- i.e. you see wear issues like your tires. Squeal is good, squalling is not. Stuck, slither, slide -- you want slither.

[Kgolf31]

Depends on the tire CSBM5.

RS3s require high slip angles for grip.

I've overdriven my tires, and never gotten results of chunking. You'll see in the below video how I looped my car and the tire marks left behind...and never have had chunking. You'll also notice that I don't baby the tires, as I finished 1st in my class and 4th overall against 129 drivers.

You can also hear the tires screaming in the final section on the high speed off-camber turn. No chunking.


It is funny how high performance tires, like Hankook RS3s, Dunlop ZIIs, and BFG Rivals do not have this problem...which leads me back to say this is a function of the tire.

As well, those hot pressures, I don't know where you got them front. Pressures determine on the rollover of the tires.

[CSBM5]

You're missing my point. All tires have a slip angle vs tractive force curve. Staying just to the left of the peak results in the same grip as just to the right of the peak. Driving them on the right of the peak results in a significant increase in tire wear for the same grip. All tires produce different sounds (or none) during the region near and over the top of the curve. The trick is to learn how a given tire feels and sounds in that region in order to extract maximum performance out of it without undue tearing/ripping of the tread compound as happens when a tire is driven over the top of the curve consistently.

[Kgolf31]

Originally Posted by CSBM5

You're missing my point. All tires have a slip angle vs tractive force curve. Staying just to the left of the peak results in the same grip as just to the right of the peak. Driving them on the right of the peak results in a significant increase in tire wear for the same grip. All tires produce different sounds (or none) during the region near and over the top of the curve. The trick is to learn how a given tire feels and sounds in that region in order to extract maximum performance out of it without undue tearing/ripping of the tread compound as happens when a tire is driven over the top of the curve consistently.

And sometimes you exceed it to rotate the car around.

The fact is, whatever it looks like on paper is never applied correctly in the real world.