Michelin Cup 2 - Delamination

[David0ff]

Michelin Cup 2 - Delamination
Track car issues

Front tires on my M4,
285/30/19 Cup2 ZP 94Y delaminating after 42 laps. Great wear assides from the delaminating.

Rear 305/30/19 98Y wearing beautifuly 0 issues.

I read about this being a common issue with CUP2s on track.
I ran them 32psi max hot f&r,
outside temperature ~26celsius.

Car settings:
Front
-4.1 Camber
0.02 degrees toe in per side
550 lbs springs
1" suspension travel before bumpstops
Whiteline sway bar full soft setting
Apex SM10 19x10 + 25
15mm spacer

Rear
-1.9 Camber
0.10 degrees toe In per side
750 lbs springs
1" travel before bumpstops.
Oem sway bar
Apex SM10 19x11 + 44
10mm spacer

Big Front splitter plus rear wing.
PowerStop track day pads F&R (excellent excellent pads,0 fade, great feel)

Car is not under steering nor over steering it's planted. Quick idea of the setup in the car pix.
Voltex wing and home made splitter and sides

Started 28psi cold F&R
I do 2 warmup laps 70-80% pace before going hard on them for the rest of the session.

Any ideas? Or are these not suitable for sustained track race pace 20min sessions.

Thx in advance

[stevehifi]

Originally Posted by David0ff

Michelin Cup 2 - Delamination
Track car issues

Front tires on my M4,
285/30/19 Cup2 ZP 94Y delaminating after 42 laps. Great wear assides from the delaminating.

Rear 305/30/19 98Y wearing beautifuly 0 issues.

I read about this being a common issue with CUP2s on track.
I ran them 32psi max hot f&r,
outside temperature ~26celsius.

Car settings:
Front
-4.1 Camber
0.02 degrees toe in per side
550 lbs springs
1.5" suspension travel before bumpstops
Whiteline sway bar full soft setting
Apex SM10 19x10 + 25
15mm spacer

Rear
-1.9 Camber
0.10 degrees toe In per side
750 lbs springs
2" travel before bumpstops.
Oem sway bar
Apex SM10 19x11 + 44
10mm spacer

Big Front splitter plus rear wing.
PowerStop track day pads F&R (excellent excellent pads,0 fade, great feel)

Car is not under steering nor over steering it's planted. Quick idea of the setup in the car pix.
Voltex wing and home made splitter and sides

Started 28psi cold F&R
I do 2 warmup laps 70-80% pace before going hard on them for the rest of the session.

Any ideas? Or are these not suitable for sustained track race pace 20min sessions.

Thx in advance

I had the same issue when I ran cup 2s on track. Front size was 265/35/19. Tires totally delaminated.

There are better choices out there: RT660, A052, AR1, CR1, RS4.

[robbo mcs]

That front splitter would be loading the front up, especially on a speed circuit. As a result, you may be significantly under sprung?

[David0ff]

Originally Posted by robbo mcs

That front splitter would be loading the front up, especially on a speed circuit. As a result, you may be significantly under sprung?

This particular circuit is not that fast, speeds are in km/h.
It's slightly bumpy on a few spots and I don't bottom out anywhere.

[dvas]

That's not delamination, that's tearing, in my view. Delamination would happen at the bead. Tearing is due to working the tires past the temperature they can handle. That's why SC2s are not great tires for HPDE format with 20 minute sessions.

[David0ff]

Originally Posted by dvas

That's not delamination, that's tearing, in my view. Delamination would happen at the bead. Tearing is due to working the tires past the temperature they can handle. That's why SC2s are not great tires for HPDE format with 20 minute sessions.

Thx for the input.
I have a video which shows it better than the pix but can't attach here.

This is a pic of both tires from the video showing the depth of the area.

So really I just have to reduce my intensity? 2-3 max laps 1-2 cool down, repeat?

[jfritz27]

You alluded to some tire temps -- if using a true pyrometer, do you have readings from inside, middle, outside? Would agree your pressures don't seem excessive, though...

[David0ff]

Originally Posted by jfritz27

You alluded to some tire temps -- if using a true pyrometer, do you have readings from inside, middle, outside? Would agree your pressures don't seem excessive, though...

Unfortunately, Saturday, my friend who has a pyro poke thing was not there so I have no readings of tire temp

[FormulaMMM]

Originally Posted by David0ff

So really I just have to reduce my intensity? 2-3 max laps 1-2 cool down, repeat?

Or just bounce from the Cups. Any reason why you're committed to them vs more durable alternatives?

[David0ff]

Originally Posted by FormulaMMM

Or just bounce from the Cups. Any reason why you're committed to them vs more durable alternatives?

Done with Cups, had a an excellent deal on 8 tires few weeks ago and got them to try out.

Yesterday another track, rear 305 delaminated before noon, same way the fronts did last weekend. Good thing I had my last 2 spare with me.

[FormulaMMM]

Originally Posted by David0ff

Done with Cups, had a an excellent deal on 8 tires few weeks ago and got them to try out.

Yesterday another track, rear 305 delaminated before noon, same way the fronts did last weekend. Good thing I had my last 2 spare with me.

Glad to hear it was an excellent deal then!

What spec cups are these? Age?

Think only specs that might hold up to hard running with our car's weight/power would be the 5-6/32" options like ZP Corvette or Ford. But too many good alternatives out there to try to make any Cups work for dedicated track purposes imo.

N spec Cups are plenty durable (tread) but heat cycle out after day 2. They're all a compromise. Too bad because when fresh they're an incredible tire, just give out too soon in one way or another.

[David0ff]

Originally Posted by FormulaMMM

Glad to hear it was an excellent deal then!

What spec cups are these? Age?

Think only specs that might hold up to hard running with our car's weight/power would be the 5-6/32" options like ZP Corvette or Ford. But too many good alternatives out there to try to make any Cups work for dedicated track purposes imo.

N spec Cups are plenty durable (tread) but heat cycle out after day 2. They're all a compromise. Too bad because when fresh they're an incredible tire, just give out too soon in one way or another.

Excellent point on the type of cup2!

My 4 x 305/30/19 were the Mustang 350R ones
My 4 x 285/30/19 were the vette ZP version
All ~1000kms street before track
All tires were 2019/20 construction

[F80Speed77]

Kind of looks like the hot pressure is still getting too high with the blistering always appearing in the middle section of the tire. I start my car out at 25psi cold and have been getting incredible wear lately with this set of RE71R.

Like others have said there are much better alternatives that are also more cost effective, look into the Goodyear Supercar 3 for a good balance of life/grip or Supercar 3R if you want more grip.

[David0ff]

Originally Posted by F80Speed77

Kind of looks like the hot pressure is still getting too high with the blistering always appearing in the middle section of the tire. I start my car out at 25psi cold and have been getting incredible wear lately with this set of RE71R.

Like others have said there are much better alternatives that are also more cost effective, look into the Goodyear Supercar 3 for a good balance of life/grip or Supercar 3R if you want more grip.

Thank you will do