PSS tire chunking - still usable? Pic inside

[IVM3]

I did a light track day and noticed some chunking on one of my front PSS tires. I tried to keep it at 36 psi hot and even did a cool down lap after every two hot laps. I know this isn't the best tire for the track, but they still have 7/32" tread left.

Is it safe to continue using these tires on the street and at the track? This pic shows the worst of the chunking. There are about four other areas with less than one inch of chunking. Thanks!

[NYG]

Temps are too high, lower the pressure. Still ok but you'll cord soon.

[IVM3]

Originally Posted by NYG

Temps are too high, lower the pressure. Still ok but you'll cord soon.

Thanks, how low of a hot pressure would you recommend aiming for? I'll also plan to rotate the front tires.

[OhioRiderAaron]

Pressure is fine, you're just over-driving them. Listen to your tires and find the sweet spot between humming and screaming. FYI the applicable organization "Tech inspectors" may give you crap about them being partially chunked. Another issue is they will probably continue to chunk worse in those same areas during the next hot session so you may want to consider "flipping" them inside to outside.

(edit: FYI 38-40PSI was always the sweet spot for me, but 36PSI isn't far off enough that I think that's causing a the chunking.)

[NYG]

Originally Posted by IVM3

Thanks, how low of a hot pressure would you recommend aiming for? I'll also plan to rotate the front tires.

It depends pressure and temperature = proportional, pressure and volume = inversely proportional.

Your pressure is good, but my PSS chunked when my outside temperatures were in the range of 190F+. Anything below and it stopped. Problem is, unless you get more camber, you'll keep heating the outside shoulder more than the rest of the tire.

[IVM3]

Thanks for the advice. I agree that temperature seems to be the primary factor. I don't even feel I was driving that hard, and didn't hear much noise from the tires.

Now I'm debating what to do. If I stop tracking on this PSS, is it worth saving it for more street mileage? They only have a few K miles on them. Or should I just plan on replacing both front tires soon and just wear them out at the track?

I was resisting modding this car but it seems camber plates are a must. If I get camber plates, would the PS4S be a trackable street tire or would I likely face the same chunking issue with hot track days? Thanks!

[dxj]

I would be fine driving those tires on the street. On the track, I would test running higher pressure. I read someone on here running higher pressures than what we typically do on these cars and I’ve been getting better tire feel and faster lap times. Feel is very subjective but higher pressure could keep you off the shoulder area and give you more tire life. For reference, I’ve crossed 50 psi and haven’t seen issues. Chalk and measure temps across tread as you’re testing.

[vrptstyly]

What was the ambient temp?

I ran the same wheels/tires on my F80 for several events so far this year. I was targeting 40 psi hot. I'm in the Northeast, ambient was in the 80's. Front end felt great. I run solo intermediate/advanced groups.

On a tire that is known for rolling over on it's sidewall. Lower pressures can't be the answer.

I definitely got a bit more wear and light feathering on that outside edge but nothing as bad as this or everything I've read on it.

[IVM3]

Originally Posted by vrptstyly

What was the ambient temp?

I ran the same wheels/tires on my F80 for several events so far this year. I was targeting 40 psi hot. I'm in the Northeast, ambient was in the 80's. Front end felt great. I run solo intermediate/advanced groups.

On a tire that is known for rolling over on it's sidewall. Lower pressures can't be the answer.

I definitely got a bit more wear and light feathering on that outside edge but nothing as bad as this or everything I've read on it.

Ambient temperature was also in the mid 80s approaching 90. Lot of left turns are rough on the front right tire. I think the clue should have been when the tires starting to feel slightly greasy, and I noticed afterwards that my lap times started to get slower. All other tires are perfectly fine so I think perhaps it was a combination of heat and perhaps not enough pressure.

[hC1001]

Originally Posted by IVM3

Ambient temperature was also in the mid 80s approaching 90. Lot of left turns are rough on the front right tire. I think the clue should have been when the tires starting to feel slightly greasy, and I noticed afterwards that my lap times started to get slower. All other tires are perfectly fine so I think perhaps it was a combination of heat and perhaps not enough pressure.

I use the PSS tire on my hpde E36 M3 track car. Its about 3200lbs. i try to target 34psi hot, thats around 28-29psi cold. I notice the tires feel greasy with higher PSI.

Thats my experience with them. When they get greasy, i normally have to take out air.

If you're still running them on the track and they get greasy, try lowering the PSI and see if that helps.