CUP2 Wear on 2020 GT350

[CRisolvato]

I obliterated a brand new set of front R-spec (98Y) cup 2s at NCM in April. I was carrying far too much speed into 2 or 3 specific corners and had not heat cycled and let them rest a day before said abuse. I was understeering badly and the tires did their best to compensate for my bad technique. When I checked the rubber I was shocked, dismayed and educated at how much $ I had wasted by being too aggressive. My previous set had 5 days on them and over 8000 total miles. These had 2.5 days and 1000 miles. In this same time frame I put nearly 60 sessions and 9.5 days on a set of N-spec cup 2s, including setting PBs the week before retiring them, and they STILL have tread left, just heat cycled out.

Some additional food for thought to add to the wealth of experience being provided by the other more seasoned drivers.

 

[Tonymustang302]

you need -2.0 front and 30psi hot. Thats how mine looked until i added more camber

 

[PurposeBuiltRacing]

Check caster, you can gain a lot of camber in the corners by adding caster, if you run only minimum caster the tire will still roll over in the corner.
This is known as " camber gain" .

the 2020 has a pin that locks the top hat caster setting... I think he has toe out

 

[PurposeBuiltRacing]

Just finished a track day on a new set of Cup2's and after I put on CC plates and the wear is still horrible on the outside. I have FP lowering springs and Steeda CC plates. The shop said they set camber to -2.9, but I would have thought the wear would have been more even. Tire pressures at the end of the runs is between 34/35.

Is this consistent to what others are seeing or is the camber still jacked?
Tire pressure too high?

View attachment 79671

So on my 2020 I am running -3 Degrees Camber Front, -1.6 Rear Camber, Front 1mm toe out each wheel, Rear 1mm toe in each wheel and I have fabulous wear now and heat variance is very even. I suspect you are running toooo much toe out...

 

[Jamesmcga]

So on my 2020 I am running -3 Degrees Camber Front, -1.6 Rear Camber, Front 1mm toe out each wheel, Rear 1mm toe in each wheel and I have fabulous wear now and heat variance is very even. I suspect you are running toooo much toe out...

Thanks everyone. I just had the suspension rechecked an updated.. Here are the new settings. Going out the road Atlanta on Wednesday so I’ll report back any findings.

 

[mavisky]

That is a lot of rear camber and is that reading that the toe is toe'd in on both front and rear?

If you're in Atlanta, I would highly suggest Gran Turismo East for your alignment work. They are recommended by nearly everyone.

 

[Egparson202]

That is a lot of rear camber and is that reading that the toe is toe'd in on both front and rear?

I agree. I wouldn’t expect this alignment to correct understeer on track. With these settings it will be especially important to focus on managing weight transfer. Too heavy on the throttle before opening up the wheel and your provoking understeer. [But really, isn’t that always the case!]

 

[PurposeBuiltRacing]

looks good except that rear camber is probably too much, the front end needs more as its initiating the turn vs following rear. front end has more compliance in the suspension as well and is what you are trying to counter with the - camber the rear has compliance too but not as much as the front axel . you may get inside shoulder wear with that much rear, I am running -1.6 rear

 

[PurposeBuiltRacing]

if you can find a guy that does string alignment I would do that all day long over these automated systems they just get things in tolerance but sloppily.

 

[blacksheep-1]

I should've paid more attention during setup..
These mustangs have to be driven into the corner, turned and driven out, overdrive them kills the handling and the tires. We had a guy that drove a Porsche and a Mustang, he would burn a set of stickers in a 40 minute practice session, 2 different animals.

 

[PurposeBuiltRacing]

I should've paid more attention during setup..
These mustangs have to be driven into the corner, turned and driven out, overdrive them kills the handling and the tires. We had a guy that drove a Pirsche and a Mustang, he would bother a set of stickers in a 40 minute practice session, 2 different animals.

Yep completely agree, overdrive them the outer edges will be hammered but the mustang needs camber for sure because there is so much compliance in the bushings

 

[JAJ]

Thanks everyone. I just had the suspension rechecked an updated.. Here are the new settings. Going out the road Atlanta on Wednesday so I’ll report back any findings. View attachment 79964

If you have the opportunity, take your car out to a parking lot and thrash it around corners hard enough to induce heavy roll in the suspension. Low speed is fine. Then take the rear wheels off and inspect the inner sidewalls of your tires to make sure they're not rubbing the upper shock mounts or other stuff up there. -2.9 negative rear camber is way past anything that Ford Performance recommends, and it puts the top of the tire a lot closer to the inside of the wheel well than the recommended settings. The risk is that you get a tire failure from the tires rubbing the infrastructure inside the wheel well.

 

[Tonymustang302]

Holy crap that rear camber lol

 

[RES_22]

You prolly see a ton of rear ABS intervention when initiating hard braking...not much rear contact patch with that level of rear camber.

 

[Jamesmcga]

You prolly see a ton of rear ABS intervention when initiating hard braking...not much rear contact patch with that level of rear camber.

Yeah, I’m going back tomorrow morning to have them reset the rear to 2.2-2.4 and front at 2.6-3.0.

does anyone have suggestions on the correct toe and caster for F/R?

I know what the supplement guide says, but I’m I’m looking for real world experience

 

[RES_22]

Seen a lot of success with zero total toe (F), -1.8 deg camber, 0.3deg total toe in (R)...provided that you are on reasonable springs and ride heights.

 

[Jamesmcga]

Seen a lot of success with zero total toe (F), -1.8 deg camber, 0.3deg total toe in (R)...provided that you are on reasonable springs and ride heights.

Yeah on FP springs.

 

[Stan Whitney]

Yeah, I’m going back tomorrow morning to have them reset the rear to 2.2-2.4 and front at 2.6-3.0.

does anyone have suggestions on the correct toe and caster for F/R?

I know what the supplement guide says, but I’m I’m looking for real world experience

I've run between 3mm-6mm (around 1/4") rear toe in, they feel about the same, both are good. I tried more but it did not improve rear grip on exit much. Usually run zero in front, because of some street driving. 0-3mm toe out should be fine, if you trailer.

 

[Egparson202]

Yeah, I’m going back tomorrow morning to have them reset the rear to 2.2-2.4 and front at 2.6-3.0.

does anyone have suggestions on the correct toe and caster for F/R?

I know what the supplement guide says, but I’m I’m looking for real world experience

Hi @Jamesmcga The new specs you’re talking about seem like a step in the right direction for a track setup. That said, for the front I’d lean toward zero toe and about -3 degrees of camber. Get all you can, then subtract a full degree for the rear with a pinch of toe in. In my opinion, this basic setup will be pretty balanced and promote good tire wear. And because you won’t have both heavy camber and toe, tire wear should be fine for transit to/from the track as well if you drive it.

 

[Egparson202]

I haven’t done anything with caster yet, but I’m thinking I’ll try increasing that as well.