HPDE experiments, results and observations

[MaX PL]

why do you always run different types of tire front and back? I've never heard of anyone doing this but you.

maybe DSC is thrown off by the different tires?

[rhyary]

Originally Posted by MaX PL

why do you always run different types of tire front and back? I've never heard of anyone doing this but you.

maybe DSC is thrown off by the different tires?

It just what I have in inventory.
There is no special reason.

DSC does not care what tires I have on the two axles, just left and right. I am careful to match left and right.

[dparm]

Originally Posted by rhyary

Not a bad day today.
The Corvette did a track record of 1:27.8. Self reported. I don't have a way to verify it. But the driver promised to send my a video link to verify. Driver said car is 3050Lbs with him sitting in the car

Previously it was a Viper ACS @ 1:28.9

The Ferrari driver (not the long hair) self reported 1:32 in previous track day. He was not keeping time today. He said.

I managed 1:37.35 but the Cup2 were gone in 5 x 20min sessions.
Cruised the 6th on 1:44, and gave up on the 7th.

Did many 1:38.x and 1:39.x

My camera got knocked off position and my 1:37.3 had the data feed, but the camera was pointing at the dashboard. Grrrrrr

Here is a spent 2016 sticker MPSCup2. It got me home.

Temp hot was inside 152 and outside 152. I am happy with the setup and the -3.5 camber. It is the first time I consume the middle of the tire.

PSI was 36 hot. I started at 31 and thought it would go up to 38. but it did not.

Are you saying you wore out a set of new Cup 2s in a single day?

[rhyary]

Originally Posted by dparm

Are you saying you wore out a set of new Cup 2s in a single day?

Yes, at NYST.
At Lime Rock my PS91 are barely used after 4 x 25min @ 63 sec

This means NYST at 1:37-1:39 is a very expensive track day, as other discovered as well.

At 1:44-2:00 it would be much cheaper

[dparm]

Originally Posted by rhyary

Yes, at NYST.
At Lime Rock my PS91 are barely used after 4 x 25min @ 63 sec

This means NYST at 1:37-1:39 is a very expensive track day, as other discovered as well.

At 1:44-2:00 it would be much cheaper

That's crazy it wore out so fast. I've run Cup 2s on my Corvette (which weighs 3700 pounds with me in it and can pull 1.5g+) and never saw them wear like that.

I looked at a track map and it does have a lot of corners, but what's the road surface like? Is it super abrasive and known to eat tires? What's your driving technique like there/on that tire? On the same track, in similar conditions, what lap times are you seeing from other tires?

[rhyary]

Originally Posted by dparm

That's crazy it wore out so fast. I've run Cup 2s on my Corvette (which weighs 3700 pounds with me in it and can pull 1.5g+) and never saw them wear like that.

I looked at a track map and it does have a lot of corners, but what's the road surface like? Is it super abrasive and known to eat tires? What's your driving technique like there/on that tire? On the same track, in similar conditions, what lap times are you seeing from other tires?

It is Motorcycle track and I guess they used a very grippy surface. It is nothing like Lime Rock

Supper grippy. Instant gratification.

[rhyary]

Drama at NYST today.
Second session and was already at 1:38.2 with the Ecsta PS91 up front.

Then I went over a 6" bolt and the rear driver immediately start losing air at 85mph.

Came to a stop between turn 2 and 3 off the track and had to wait to lunch time to change the spare and drive home.

One one hand, what a waste of a track day, on the other I just got way with a flat at 85mph with no damage and no issues.

I would call it good, and won't complain.

The track recovery track picked me up and I was able to find the bolt and picked it up.

What the hell a bolt is doing in the middle of the track from the day before? Clearly it was not from our day.

[dparm]

Originally Posted by rhyary

It just what I have in inventory.
There is no special reason.

DSC does not care what tires I have on the two axles, just left and right. I am careful to match left and right.

I'm not sure I would completely agree with that. DSC doesn't directly know that you may have different grip levels at those axles, but it is able to infer it based on how the car is handling and of course the sensor inputs (like the wheel speed sensors).

If anything, I would hypothesize that the DSC programming is optimized to assume you have the same tire on all four wheels. If you are getting a lot of understeer because the front tire compound isn't as sticky, it will be cutting the throttle or brushing the brakes to try and tuck the nose into a corner.

You could test this theory pretty easily by running a different front tire one session and then swapping back to a matched set the next one and looking at the telemetry.

[dparm]

Originally Posted by rhyary

Drama at NYST today.
Second session and was already at 1:38.2 with the Ecsta PS91 up front.

Then I went over a 6" bolt and the rear driver immediately start losing air at 85mph.

Came to a stop between turn 2 and 3 off the track and had to wait to lunch time to change the spare and drive home.

One one hand, what a waste of a track day, on the other I just got way with a flat at 85mph with no damage and no issues.

I would call it good, and won't complain.

The track recovery track picked me up and I was able to find the bolt and picked it up.

What the hell a bolt is doing in the middle of the track from the day before? Clearly it was not from our day.

That stinks, but in the grand scheme of shit that can happen at a track, that's not so bad. This is why you bring spare tires. :-)

[rhyary]

Originally Posted by dparm

I'm not sure I would completely agree with that. DSC doesn't directly know that you may have different grip levels at those axles, but it is able to infer it based on how the car is handling and of course the sensor inputs (like the wheel speed sensors).

If anything, I would hypothesize that the DSC programming is optimized to assume you have the same tire on all four wheels. If you are getting a lot of understeer because the front tire compound isn't as sticky, it will be cutting the throttle or brushing the brakes to try and tuck the nose into a corner.

You could test this theory pretty easily by running a different front tire one session and then swapping back to a matched set the next one and looking at the telemetry.

My main goal is to drive with DSC=off and manage traction.

Sometimes I just want to drive "harder" with less worries. Perhaps to experiment with different lines, or first time for the season at a particular track.

I don't necessarily disagree with you. I honestly don't know technically how the DSC is programmed.

For what I do, the front and rear do not have to match on days I am not trying to do PB.

Basically, unless I have R7 or A7, makes not difference what I do on a dry day.

[rhyary]

My Future Classic F80 hubs are taking a trip to Core4 to do a pressed in conversion. My main motivation to do this is for simplicity. I just want to know the old one off and press a new one in.

In addition, I don't want to deal with drilling should one break. I don't want to figure out the torque the new ones. So my motivation is perhaps is simplicity and the bonus is strength.

In addition, the studs will be 1.5 thread replacing 1.25 per Core4 recommendation.

[dparm]

Originally Posted by rhyary

My main goal is to drive with DSC=off and manage traction.

Sometimes I just want to drive "harder" with less worries. Perhaps to experiment with different lines, or first time for the season at a particular track.

I don't necessarily disagree with you. I honestly don't know technically how the DSC is programmed.

For what I do, the front and rear do not have to match on days I am not trying to do PB.

Basically, unless I have R7 or A7, makes not difference what I do on a dry day.

If your main goal is to drive without DSC, then you need to remove other variables like mismatched tires and changing to different tires all of the time. It's way too much to manage at once. Did you get your understeer math channel built, by the way?

I'm still fascinated that all of those tires, save for the Hoosiers, give you basically the same lap times.

[tsk94]

Originally Posted by dparm

If your main goal is to drive without DSC, then you need to remove other variables like mismatched tires and changing to different tires all of the time. It's way too much to manage at once. Did you get your understeer math channel built, by the way?

I'm still fascinated that all of those tires, save for the Hoosiers, give you basically the same lap times.

I was just about to post the same thing.

You seem quite serious on improving your driving and understanding of vehicle dynamics, but your current approach is almost certainly a hindrance.

If you're not at the point where you can confidently, and quickly, drive with DSC off with street tires, then using mismatched sets of tires front and rear will definitely not help - and the main issue being is you swap to different mismatched combinations almost every track day! If you want to improve your driving at the limit, your trail braking and the ability to confidently run with DSC off at all times, then you should eliminate these self-imposed variables you set on yourself every time out on track. You're hurting your own progression by drastically changing your cars handling dynamics every time you run a different front and rear tire combo and switch to a different combo the next time out. If you don't care about delaying your own progression then carry on, but otherwise I would strongly advise running both the same tires front and rear and using the same set of tires for a few times to build some consistency and allow you to solely focus on developing technique. At the very least, if you run mismatched sets, run the same mismatched set consistently..

There was a great article on the Cup 2's posted in the Wheel+Tire section that clearly outlines how different every tire compound is and why mismatched sets are a poor approach.

[rhyary]

Originally Posted by tsk94

I was just about to post the same thing.

You seem quite serious on improving your driving and understanding of vehicle dynamics, but your current approach is almost certainly a hindrance.

If you're not at the point where you can confidently, and quickly, drive with DSC off with street tires, then using mismatched sets of tires front and rear will definitely not help - and the main issue being is you swap to different mismatched combinations almost every track day! If you want to improve your driving at the limit, your trail braking and the ability to confidently run with DSC off at all times, then you should eliminate these self-imposed variables you set on yourself every time out on track. Your hurting your own progression by drastically changing your cars handling dynamics every time you run a different front and rear tire combo and switch to a different combo the next time out. If you don't care about delaying your own progression then carry on, but otherwise I would strongly advise running both the same tires front and rear and using the same set of tires for a few times to build some consistency and allow you to solely focus on developing technique. At the very least, if you run mismatched sets, run the same mismatched set consistently..

There was a great article on the Cup 2's posted in the Wheel+Tire section that clearly outlines how different every tire compound is and why mismatched sets are a poor approach.

Are you speaking from experience?
Have you tried doing what I am doing?
Just curious.

Let's agree to disagree. My setup is giving me the exact experience that I want, albeit I am slower. I am learning what I need to learn, and pretty sure when I mount an A7 I will be doing a PB in the fall.

[Bartledoo]

Originally Posted by rhyary

Are you speaking from experience?
Have you tried doing what I am doing?
Just curious.

Let's agree to disagree. My setup is giving me the exact experience that I want, albeit I am slower. I am learning what I need to learn, and pretty sure when I mount an A7 I will be doing a PB in the fall.

Just curious, but how are you confirming that you've learned what you need to learn? Has an expert in the matter told you this? People here are trying to help you, but you always respond by asking if they've tried your method. Of course nobody has tried your method. It is very well known to be the wrong method, and you are proving it.

Insert the Tommy Boy quote about the butcher's ass here.

Edit: I'm sorry man, I'm an ass.

[rhyary]

Originally Posted by dparm

If your main goal is to drive without DSC, then you need to remove other variables like mismatched tires and changing to different tires all of the time. It's way too much to manage at once. Did you get your understeer math channel built, by the way?

I'm still fascinated that all of those tires, save for the Hoosiers, give you basically the same lap times.

My goal is to drive with DSC off when I want to focus on controlling the car and not going for lap time.

When I go for lap time, I keep the DSC on for extra safety.

I approach things methodically, but on every track day, I don't have the same objectives.

I sincerely appreciate all the comments and advise this board has provided me, so with out getting into the goal of the day, the term "improving my driving" is too general to my goals for that day.

I have many goals, that collectively do make me a better driver, but not all goals are to make a PB every single time.

I can improve my trail braking on ANY tires I chose to run. Makes no difference if I am on $100 used cup2 or $400 new cup2

It makes no difference if my rears are RR or Super Sport. And for trail braking timing and slow release into the apex, make no difference if I am on 275/35/19 or 295/30/19. It is what it is and I am learning to mange it.

That, makes me a better driver. So when I get a flat at 85mph, and the car behaves weird, I say, "no problem, it is like the shitty tires i was on last trackday"

[CorruptCommie]

I was just wondering what I would tell a student if I saw mismatched tires. I know what I'd tell the CDI, just not sure it'd be repeatable to the student.

[rhyary]

Originally Posted by CorruptCommie

I was just wondering what I would tell a student if I saw mismatched tires. I know what I'd tell the CDI, just not sure it'd be repeatable to the student.

What is CDI?

[gmx]

With the latter part of the conversation, re mixing and matching compounds. I don't necessarily disagree. As long as you sense what the car is delivering and realise you are dedicating time to learn and experience these characteristics directly in person rather than hypothetically.

I once used rear retail Cup2 19" in 265 with a Z221 18" 265 front. I lost the lock nut and couldn't change the rears. Solution? Just send it. Basically a super street tyre with a top tier semi-slick. It was interesting, extremely sensitive to trail brake for example. I did have a video on YT but the beta studio editing completely messed up the audio. I have to wait till fibre gets connected before re-uploading, 4th world internet things.

Did I get a PB? Of course not.
Was it hilariously imbalanced? Yup.
Did I gain experience, finesse and probably pay more attention to controlling this thing esp on pre apex phases of a corner? For sure.
Did I know it was going handle like this? Definitely. Except no one can quantify how "bad" the balance really is until you actually do it.

In relation to the last question and in much finer detail; it's the same as people testing square vs staggered or evaluating various stagger setups.

[ThunderMoose]

Originally Posted by rhyary

What is CDI?

Chief Driving Instructor.

[tsk94]

Originally Posted by rhyary

Let's agree to disagree

You can do what you want man. I've said it once and I'll say it again, people provide you this constructive criticism in order to help you.

Like I mentioned previously, it seems like you taking your driver improvement quite seriously. Then people will come in and offer advice to try to help you, many of them instructors or with vast amounts of driving experience, yet you shrug it off. I can't think of many instructors or coaches who wouldn't agree that your approach to tire usage isn't holding you back from progressing driving technique at a 'normal' rate. What does your current 'coach' think of the situation? For that matter WHO is coaching you?

If you're still not confident or capable to drive quickly with DSC off with street tires then I think that speaks for itself. If you want to improve you need to eliminate as many variables as possible so you can purely work on technique. Maybe I'm wrong, perhaps you really don't care about improving so you continue along your 'approach'. What exactly are you trying to accomplish with these ever changing, nonsensical tire combination and variations?

I'm pretty sure I saw in another thread that you're running a carbon ceramic Brembo BBK and 4-way motorsport JRZ's. It seems like budget is clearly not an issue, so why not just buy complete sets of tires

[rhyary]

Originally Posted by ThunderMoose

Chief Driving Instructor.

Thanks.
I made sure to clear my setup with LRP organizer a head of time to avoid surprises on tech inspection.