[dimab0]

These are the Michelin PS4 that came with the car, ~15 months ago. After 4th and most recent track day, they are loosing chunks of rubber. I haven't seen this before. I assume they are dead and need to be replaced, right? What causes chunks to break off?

Planning to replace with new set of the same - unless there is consensus that something else is way better? I use it for 95% daily commute, 5% track.

[BMWRacer523]

what kind of track surface at the corners? asphalt or concrete?

[dimab0]

Originally Posted by BMWRacer523

what kind of track surface at the corners? asphalt or concrete?

Asphalt, 90% sure. This is from Autobahn Country Club in Joliet, IL.

[BMWRacer523]

Originally Posted by dimab0

Asphalt, 90% sure. This is from Autobahn Country Club in Joliet, IL.

Oh yeah, thats a well maintained facility. Def asphalt. I've seen tracks like Sebring tear tires up like that because many sections are concrete and they are very abrasive. Are you sure this is from track? Do you regularly commute on crappy torn up roads?

[moproblems]

Chunking can happen when tires are quite overheated, but I'm guessing it's a combo of overheat and just being worn out.

Did you run with revmatch?

[dimab0]

Originally Posted by BMWRacer523

Oh yeah, thats a well maintained facility. Def asphalt. I've seen tracks like Sebring tear tires up like that because many sections are concrete and they are very abrasive. Are you sure this is from track? Do you regularly commute on crappy torn up roads?

I do commute daily on these. But they lost chunks only at this last track day. The front left tire is worst, I suspect it's due to abs kicking in that gives it more stutter under braking and more right turns than left.

[dimab0]

Originally Posted by moproblems

Chunking can happen when tires are quite overheated, but I'm guessing it's a combo of overheat and just being worn out.

Did you run with revmatch?

I did run with rev match but I don't understand how that related to tires.
Probably they are just worn at this point.

[pinky_chi]

I had similar looking chunking on a set of PS4S on my other car when I ran them too hot. Those tires though were much newer so the chunking only happened on the shoulders.

[pinky_chi]

Also I think for your use case the oem star spec PS4s are the still the best choice. There are more track oriented tires that can take more heat but they dont do well in the rain and are not comfortable on the street.

https://grassrootsmotorsports.com/ar...qMRLYWHotW0TT4

[beachBmmr]

If you need wet/winter driving them the mps4s* are the way to go. A little soft and numb for the track but given your usage should be good to go. There's nothing else going to give you good wet traction and decent dry traction like that tire.

[moproblems]

Originally Posted by dimab0

I did run with rev match but I don't understand how that related to tires.
Probably they are just worn at this point.

I meant revmatch is a group that runs there somewhat frequently. Not the revmatch feature on the car, sorry to be confusing.

[moproblems]

Originally Posted by beachBmmr

If you need wet/winter driving them the mps4s* are the way to go. A little soft and numb for the track but given your usage should be good to go. There's nothing else going to give you good wet traction and decent dry traction like that tire.

Winter driving on a ps4s? You must be insane.

[dimab0]

Originally Posted by moproblems

I just know the guys that run it, sorry.

Oh rev match is some organization? Then no, not with them. I thought you meant the feature on the m4 to auto rev match when shifting.

[beachBmmr]

Originally Posted by moproblems

Winter driving on a ps4s? You must be insane.

Im in texas, formerly from ny. Winter here is just rain. Occasionally

[M4Tejas]

Originally Posted by beachBmmr

Im in texas, formerly from ny. Winter here is just rain. Occasionally

Except for the massive "ice storms" i have been though here in Texas the last 46 years!

[jmg]

Looks just like my front driver side started chunking after 4 CW track days. Most notably after neglecting to check temps and pressure during a triple digit day at Spring Mountain, which has several high speed right turns. With how heavy our G8Xs are, and how much softer the MPS4S* compound is at the corner compared to the non-star, it seems to be much more temperature and pressure sensitive.

I've since mounted Cup2 (240)... I'll be posting an update on wear characteristics and overall performance when I get my car back and get some more seat time. From my one track day on these tires, however, I've already beat my PB and they are pretty damn good.

[dimab0]

Originally Posted by jmg

Looks just like my front driver side started chunking after 4 CW track days. Most notably after neglecting to check temps and pressure during a triple digit day at Spring Mountain, which has several high speed right turns. With how heavy our G8Xs are, and how much softer the MPS4S* compound is at the corner compared to the non-star, it seems to be much more temperature and pressure sensitive.

I've since mounted Cup2 (240)... I'll be posting an update on wear characteristics and overall performance when I get my car back and get some more seat time. From my one track day on these tires, however, I've already beat my PB and they are pretty damn good.

Thanks. Good to hear. I've heard cup2 wear more quickly. Not sure if that's worse than mp4s* chunking eventually.

[jmg]

Originally Posted by dimab0

Thanks. Good to hear. I've heard cup2 wear more quickly. Not sure if that's worse than mp4s* chunking eventually.

The MPS4S* has more of the Cup2 compound on it's outer tred, so I imagine it will be about the same or worse, but I figure that since the MPS4S* is a compromise for street wear and occasional track use, I might as well get the track tire for optimal grip since I don't daily drive it!

[beachBmmr]

Originally Posted by jmg

Looks just like my front driver side started chunking after 4 CW track days. Most notably after neglecting to check temps and pressure during a triple digit day at Spring Mountain, which has several high speed right turns. With how heavy our G8Xs are, and how much softer the MPS4S* compound is at the corner compared to the non-star, it seems to be much more temperature and pressure sensitive.

I've since mounted Cup2 (240)... I'll be posting an update on wear characteristics and overall performance when I get my car back and get some more seat time. From my one track day on these tires, however, I've already beat my PB and they are pretty damn good.

Chunking in a dead giveaway of overheating..
the 4s's are not as heat tolerant as the cup2, and the sidewalls are much softer. Cup2* are a lot stickier at 180 degrees.

[beachBmmr]

Originally Posted by BMWTEJAS

Except for the massive "ice storms" i have been though here in Texas the last 46 years!

Yeah but nobody drives in that weather.... Ive completely lost my tolerance for cold. First winter I never wore a jacket...now I have a hoody on at 65 degrees...

[M4Tejas]

Originally Posted by beachBmmr

Yeah but nobody drives in that weather.... Ive completely lost my tolerance for cold. First winter I never wore a jacket...now I have a hoody on at 65 degrees...

Been driving it for 46 plus years man. Michelin PS4's on 2 cars the last 2 years. Just slow it down.

Yea used to be in Local Union 146 when i was a kid...coldest I ever felt in was on the runway at Carswell AFB. I swear it was colder than the 4 years I was in Germany! Something about the tarmac, the concrete super cools the air! I almost seen grown men cry that day. They said "drag up". Tools go back in the gang box. Go the F home! Only one time did I see that in the Union. That one day!