GR Yaris Do not buy CUP2 tyres for track use

991RS

991RS

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Hello,

Disclaimer : This concern TRACK USE
I am used to cup 2 tyres in 325/265 width N spec and they are very very good. Very good grip and they last a very long time.
I wanted to try them on my Yaris GR, 8.5 width wheel, 245/35.

Good grip but at half day the front left tyre (no surprise, clockwise track) was worn, horrible noise coming out from wheel on hard right turns.
Pieces of rubber shredded, had to switch left and right, then drove some more and again, the previously "good" right tyre that went on the left side was worn too and same horrible noise on hard turns.

Next trackday I will switch front and rear, and left/right midday.
So only 2 track days....and those 2 track days were done without any glory !

The worst part is a friend of mine told me about this but I guess I wanted to check by myself :ROFLMAO:
They have the same issues on Alpine cars

So : CUP2 tyres are not good at all on small width for track use.
This is really incredible compare to 325/265 width

Next will be Nankang AR-1, 235/40. I think this real semislick tyre will have more grip whereas it's 10mm narrower.

Sorry for my english, I am french.

1705489675923.webp


1705489675929.webp
 
991RS said:
Next will be Nankang AR-1, 235/40. I think this real semislick tyre will have more grip whereas it's 10mm narrower.
Click to expand...
Before going AR-1, check out new Nankang CR-S!
Or if also used on road also, AD09.

CUP2 is heat sensitive...
 
991RS said:
Hello,

Disclaimer : This concern TRACK USE
I am used to cup 2 tyres in 325/265 width N spec and they are very very good. Very good grip and they last a very long time.
I wanted to try them on my Yaris GR, 8.5 width wheel, 245/35.

Good grip but at half day the front left tyre (no surprise, clockwise track) was worn, horrible noise coming out from wheel on hard right turns.
Pieces of rubber shredded, had to switch left and right, then drove some more and again, the previously "good" right tyre that went on the left side was worn too and same horrible noise on hard turns.

Next trackday I will switch front and rear, and left/right midday.
So only 2 track days....and those 2 track days were done without any glory !

The worst part is a friend of mine told me about this but I guess I wanted to check by myself :ROFLMAO:
They have the same issues on Alpine cars

So : CUP2 tyres are not good at all on small width for track use.
This is really incredible compare to 325/265 width

Next will be Nankang AR-1, 235/40. I think this real semislick tyre will have more grip whereas it's 10mm narrower.

Sorry for my english, I am french.
Click to expand...
Cup2 are quite sensitive on heating process, ie. they need gentle heat up, othervise it might end up being torn apart?
I have driven few track days with cup2 and they have worked and worn fine. Their heat tolerance could be better but its okeyish.

I consider them 50/50 track tire so maybe proper semi slicks are way to go if pushed harder.
 
Onehp said:
Before going AR-1, check out new Nankang CR-S!
Or if also used on road also, AD09.

CUP2 is heat sensitive...
Click to expand...
I'd like to try CR-S but not available yet, maybe in few days.
And after buiyng an expensive set of tyres, worned them in +/- one trackday, some cheap AR-1 are welcome đŸ˜‚
That said it's not impossible I buy CR-S.

I have read that they are quicker than AR-1.
 
991RS said:
Hello,

Disclaimer : This concern TRACK USE
I am used to cup 2 tyres in 325/265 width N spec and they are very very good. Very good grip and they last a very long time.
I wanted to try them on my Yaris GR, 8.5 width wheel, 245/35.

Good grip but at half day the front left tyre (no surprise, clockwise track) was worn, horrible noise coming out from wheel on hard right turns.
Pieces of rubber shredded, had to switch left and right, then drove some more and again, the previously "good" right tyre that went on the left side was worn too and same horrible noise on hard turns.

Next trackday I will switch front and rear, and left/right midday.
So only 2 track days....and those 2 track days were done without any glory !

The worst part is a friend of mine told me about this but I guess I wanted to check by myself :ROFLMAO:
They have the same issues on Alpine cars

So : CUP2 tyres are not good at all on small width for track use.
This is really incredible compare to 325/265 width

Next will be Nankang AR-1, 235/40. I think this real semislick tyre will have more grip whereas it's 10mm narrower.

Sorry for my english, I am french.
Click to expand...
Exact same issue
As you can see its really this second outter thread that gets destroyed.
I think its too soft, cant deal w/ higher lateral forces
I was paying extra attention on tyre temperatures.
Similar issue w/ otherwise excellent Continental SpC7
PS4s had some shoulder wear
GY EF1SS wear was fully even
All tyres used in same conditions, abused on same track, w/ lap times 41.4-41.8s
20220824_220855-COLLAGE.webp
 
nankangs are not a silver bullet too. buddy of mine destroyed several of them in a same way: plenty of rubber left, but internally damaged…

c93cbbb6-640c-4b50-b33d-54bab5e9ce4f.webp
 
:oops: :oops: :oops: What's going on with the side of this tyre ?đŸ˜¨
Surface (I mean the part in contact with the ground) is OK, maybe tiny camber settings needed...
 
991RS said:
:oops: :oops: :oops: What's going on with the side of this tyre ?đŸ˜¨
Surface (I mean the part in contact with the ground) is OK, maybe tiny camber settings needed...
Click to expand...
Bad vulcanisation/adhesion of the sidewall rubber to the sidewall weave, causing delamination?
 
This is not related to pressure and/or geo.
As I said owners of Alpine cars have the same problem quite often no matter camber settings and pressure setting.

I have KW clubsport V4 with a geo setup mainly for track.
Tyre pressure :
front : I tried between 2.0 and 2.2 all day long
rear : I tried between 1.9 and 2.1 all day long
 
TTomas said:
Hot\cold pressures? Geo?
Click to expand...
I went with 2.35/2.15 bar cold, 2.7/2.4 bar hot, as lower pressures resulted in excessive shoulder temp/wear. My track has very high grip (I pulled 1.4-1.5G's lateral with cup2) I guess it has to do with the fact that I need higher tyre pressures...

My geo:
camber -3°/-2.7°
toe: 0.5mm in/2mm in
 
I spoke to Michelin a few months ago, as I tried Cup 2s (225) on track but didn't love the wear pattern and grip. Turned out I was running them too low.

2.3-2.7 (33-39 PSI) when hot is the optimal pressure. They sent me the attached document.
 

Attachments

Second track day last weekend with same cup2.

To summarize, the tyre you see in pictures has done :
- One track day on the front axle with left/right exchange mid-day (low ambiant temperature)
- One track day on the rear axle with left right exchange mid-day (low ambiant temperature)
Second track day was very wet all day so I guess not hard for the tyre, except I oversteered (on purpose) all day long (it was very fun đŸ˜… )


Next weekend Nurburgring TF with new AR1 :love:

1709980022810.webp


1709980022816.webp
 
tbydwrds said:
I spoke to Michelin a few months ago, as I tried Cup 2s (225) on track but didn't love the wear pattern and grip. Turned out I was running them too low.

2.3-2.7 (33-39 PSI) when hot is the optimal pressure. They sent me the attached document.
Click to expand...
Yes but the Yaris is relatively light so we should be able to run lower tyre pressure. 2.3 / 2.7 seems pretty high to me.
On a 991 GT3RS nobody runs 2.3/2.7 it's too high whereas the car is heavier than the Yaris.
 
Orion said:
I went with 2.35/2.15 bar cold, 2.7/2.4 bar hot, as lower pressures resulted in excessive shoulder temp/wear. My track has very high grip (I pulled 1.4-1.5G's lateral with cup2) I guess it has to do with the fact that I need higher tyre pressures...
Click to expand...
Same thing, It seems very high too me, but if it worked for you why not.....
What is the feeling of the car with such tyres pressure ? Any good laps time ?
I wonder.
 
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