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      12-08-2019, 10:03 AM   #10781
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I have no idea why you guys monkey around with different tires and compounds. That is a complete waste of time and money .......especially if your trying to save money or go fast. Plus a good suspension is set up for a particular tire. You can't just throw on a new tire and expect it to perform without optimizing the setup.
This could go for any number of modifications. It's pretty well documented what works on this platform. You don't need to develop it yourself.
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      12-08-2019, 10:19 AM   #10782
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Quote:
Originally Posted by PrimeBMW View Post
I have no idea why you guys monkey around with different tires and compounds. That is a complete waste of time and money .......especially if your trying to save money or go fast. Plus a good suspension is set up for a particular tire. You can't just throw on a new tire and expect it to perform without optimizing the setup.
This could go for any number of modifications. It's pretty well documented what works on this platform. You don't need to develop it yourself.
Because it is fun to experiment, test, figure out the differences, learn new stuff. This hobby is not about saving money. It is about having fun within the limit of a budget. And budget is an individual thing. Take 10 people with the same income, and each will allocate different amount to hobbies. Take 10 people with same budget to the same hobby (HPDE in this case) and each would select using the same amount on different stuff. So there is no point asking why we do what we do.

There is a point in sharing information so that we can learn from each other based on the collective experiences we all have.

It gets more specific than that. This is a subform of track experiences. The going around the track is so complicated, with so many variables, there will never be a one answer that fits all.

In this case take camber as an example. My point was that we can't just agree on "best camber" because -3.5 with R7 265/35/19 would be faster than -2.5 RR 235/35/19 but at the delta cost of +$600 a set.

We can argue, and we should, on the minute details, but these are the choices we need to make.

And having choices and making decisions is part of the fun.

Isn't it?
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      12-08-2019, 03:04 PM   #10783
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Quote:
Originally Posted by rhyary View Post
I thought I was clear that it was between two slicks, RR and R7
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Originally Posted by rhyary View Post
with the exception of the R7 which is also slick
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Originally Posted by tsk94 View Post
Even if the 235 has a larger contact patch, the real difference comes from the difference in rubber compound. The R7's are considerably stickier then the RR's, thus the difference in grip.

For example, a set of 255 slicks will be faster then a set of 295 AR1/RR's, etc. comparable R-comp tires. They may overheat easier and wear more quicker due to the the narrower contact patch - but they will be faster.
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Originally Posted by roastbeef View Post
because of the variance of treadwear ratings differing between brands coupled with environmental variables, it might be impossible to even make that comparison. there is going to be an overlap somewhere with a high grip skinny tire, and a lower grip, wider tire, but its going to be almost impossible to determine where.
I just wanted to clarify that in my early comment I was referring to actual slicks (Pirelli, Michelin, Conti, etc), not a DOT r-comps like a R7 or RR that happens to have a basically 'slick' tread pattern.

I will agree with Rhyary though, the experimentation is certainty part of the fun!
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      12-08-2019, 03:58 PM   #10784
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Quote:
Originally Posted by rhyary View Post
I have lap times to correlate to my statements.
But, non of it is scientific so take it as observation.

For example, with the RR 235, I was easily doing multiple 1:37 on multiple sessions through out the day throughout the season.

On the ADOR8, while my fastest time is 1:37.2, most of the laps were 1:38-39 and only few sessions in the fall when it was cooler.
Because AD08R is still a road tyre and only good for 1 hotlap, maybe 2 if the suspension is setup correctly. All the WTAC teams run this as a control tyre and throw them out after 1HC or only keep scrubs to dial in setup. They lose peak grip but are consistent either down to cords or until HC out unlike Hankook RS4 which gradually lose grip each HC.
My 295s HC'd out (heaps of roll racing). My 285s did 1 wet session at WTAC :winning.
I really don't understand why people try do "endurance" sessions on AD08Rs/RS4 and even RE71R. Good way to kill them and not get much out of them as a result.

Quote:
Originally Posted by rhyary View Post
With PS4S 275/30/19 front I did 1:38 on semi wet track. So it is fantastic tire, but not compares to RR and R7 in the dry
Yes, people run these before the cross-over to dry tyre. It has a soft sidewall so your temperature spread between inner, centre, outer will be different compared to the others.

You're not getting the most out of RR/R7 if your time is the same as AD08R. Yoko's next step, the A050 is at least 0.7sec quicker than fresh AD08R. RR/R7 are another big step above that man.

See video of my scrubbed AD08Rs: There is an obvious behaviour change on the second lap.


Use a probe, start noting down surface temps and other track conditions, tyre temps, laps etc. You collect data for other aspects of your own driving, right? May as well grab this stuff otherwise it's pew pew in the dark or purely based off feel.
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      12-08-2019, 10:37 PM   #10785
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i have actually dismissed the idea of a probe. if listened to a few podcasts/webinars and talked with people at the track and a really nice garage neighbor that let me play with one. the general consensus is you have to work up to a hot lap, but not get sloppy to intentionally overheat the tires, then come in the pits hot, and immediately probe the tires. otherwise, the tire carcass absorbs and begins to blur the surface temperature differences. from what i have found, you really have to have someone waiting for you to jump out and probe the tires as soon as you come in, rather than after your cool down lap, park, take it out of the case...
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      12-09-2019, 08:12 AM   #10786
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Just leave it on the pit wall and get out and do it mid session
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      12-09-2019, 11:53 AM   #10787
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Quote:
Originally Posted by roastbeef View Post
i have actually dismissed the idea of a probe. if listened to a few podcasts/webinars and talked with people at the track and a really nice garage neighbor that let me play with one. the general consensus is you have to work up to a hot lap, but not get sloppy to intentionally overheat the tires, then come in the pits hot, and immediately probe the tires. otherwise, the tire carcass absorbs and begins to blur the surface temperature differences. from what i have found, you really have to have someone waiting for you to jump out and probe the tires as soon as you come in, rather than after your cool down lap, park, take it out of the case...
I agree.
It is really hard to get valid data without onboard telemetry and a pit crew.
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      12-09-2019, 01:25 PM   #10788
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Make friends with someone in another run group and do it for eachother
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      12-09-2019, 01:45 PM   #10789
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Critique my tire wear/alignment.

Front camber: -2.4
Front toe: 0
Front caster: 7.0

Rear camber: -2.0
Rear toe: 0


I tried to have these rotated after every track day but that really just means swapping the entire tire/wheel from one side to the other on the same axle, which still keeps the outside on the outside. I shoot for 34-35psi hot which is 27-28psi cold.

I also put about 5,000 street miles on them in this time. Note that MSR Cresson has a lot of left turns, if you aren't familiar.

7/19/19: COTA, 98 degree ambient, 88 minutes on track
9/17/19: MSR Cresson 1.7 CCW, 94 degree ambient, 54 minutes on track
9/28/19: MSR Cresson 1.7 CCW, 95 degree ambient, 154 minutes on track
9/29/19: MSR Cresson 1.7 CCW, 95 degree ambient, 72 minutes on track
11/17/19: MSR Cresson 1.7 CCW, 66 degree ambient, 87 minutes on track

(total track time = approx. 453 minutes)
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      12-09-2019, 10:38 PM   #10790
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You'll get plenty of opinions based on tire wear, hard to say with the 5000 street miles. The front inside edges are definitely worn from that driving. The rear tires look like they'd be happy with 2-3 psi less hot. I personally would bump up the camber on both ends by a bit, but if you're going to continue street driving the car as well its just going to wear the front insides out quicker. Overall the wear looks reasonable given the driving you've done.
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      12-10-2019, 01:15 AM   #10791
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not bad at all. like fsmtnbiker said, take a few pounds out of the rear. fronts look nice, no cupping or anything weird. might be able to do slightly more camber, but overall, looks pretty healthy- especially if you're happy with how she drives.
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      12-10-2019, 01:22 AM   #10792
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Quote:
Originally Posted by dparm View Post
Critique my tire wear/alignment.

Front camber: -2.4
Front toe: 0
Front caster: 7.0

Rear camber: -2.0
Rear toe: 0
In the world of M3's, I've always heard that a bit of Rear Toe In helps with braking stability. Do Corvettes benefit from that too? Or no?
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      12-10-2019, 01:30 AM   #10793
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Originally Posted by StripclubDJ View Post
As for cost , obviously not cheap
But with the amount of time it takes me to pay attention to littlest of details nobody cares about, it's a bargain in my eyes
Don't tell me that's Ed's lol
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      12-10-2019, 01:31 AM   #10794
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Quote:
Originally Posted by M3 Number 86 View Post
Quote:
Originally Posted by StripclubDJ View Post
As for cost , obviously not cheap
But with the amount of time it takes me to pay attention to littlest of details nobody cares about, it's a bargain in my eyes
Don't tell me that's Ed's lol
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      12-10-2019, 01:40 AM   #10795
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My car turned significantly better with the more tire I had in front.

Is your M3 rear engine? Lol
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      12-10-2019, 01:41 AM   #10796
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Quote:
Originally Posted by dogbone View Post
Quote:
Originally Posted by dparm View Post
Critique my tire wear/alignment.

Front camber: -2.4
Front toe: 0
Front caster: 7.0

Rear camber: -2.0
Rear toe: 0
In the world of M3's, I've always heard that a bit of Rear Toe In helps with braking stability. Do Corvettes benefit from that too? Or no?
I think overall stability. I've never seen anyone with zero toe in the rear!!
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      12-10-2019, 01:45 AM   #10797
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Quote:
Originally Posted by dparm View Post
Critique my tire wear/alignment.

Front camber: -2.4
Front toe: 0
Front caster: 7.0

Rear camber: -2.0
Rear toe: 0


I tried to have these rotated after every track day but that really just means swapping the entire tire/wheel from one side to the other on the same axle, which still keeps the outside on the outside. I shoot for 34-35psi hot which is 27-28psi cold.

I also put about 5,000 street miles on them in this time. Note that MSR Cresson has a lot of left turns, if you aren't familiar.

7/19/19: COTA, 98 degree ambient, 88 minutes on track
9/17/19: MSR Cresson 1.7 CCW, 94 degree ambient, 54 minutes on track
9/28/19: MSR Cresson 1.7 CCW, 95 degree ambient, 154 minutes on track
9/29/19: MSR Cresson 1.7 CCW, 95 degree ambient, 72 minutes on track
11/17/19: MSR Cresson 1.7 CCW, 66 degree ambient, 87 minutes on track

(total track time = approx. 453 minutes)
34/35 always seem too hot for me. Looks like the rears could come down some with wear more in the middle due to over inflation?

The edit: passenger front side I can't tell if anything is wrong but on one tire it has a strange valley towards the outside. For me I experienced that when I had blown suspension but since it's a new car it's most likely not that. But are the surfaces shitty at the track and is the wheel stuttering up abs down a lot? Maybe it's just pushing.
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      12-10-2019, 05:58 PM   #10798
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thought i'd share the latest oil report. includes 3 track days a few autoxes. All on redline's 50wt racing oil. I did the TBN as I was curious how bad it would be, but not bad at all. Easily a 3k mi oil change, which is what a lot of people run for OCIs anyway. Still, the motor looks very strong.

Looks great, but toying with the idea of selling the car...

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      12-10-2019, 09:52 PM   #10799
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Quote:
Originally Posted by M3 Number 86 View Post
34/35 always seem too hot for me. Looks like the rears could come down some with wear more in the middle due to over inflation?

The edit: passenger front side I can't tell if anything is wrong but on one tire it has a strange valley towards the outside. For me I experienced that when I had blown suspension but since it's a new car it's most likely not that. But are the surfaces shitty at the track and is the wheel stuttering up abs down a lot? Maybe it's just pushing.
It's probably more related to the specific track I spent a lot of time at. It's hard on that side of the car. Also, that "shaving" look is probably caused by the tire being laterally dragged in some turns. My factory MPSS and MPSC2 did it too. I was able to reduce it with some pressure adjustments at Fall-Line's advice.
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      12-12-2019, 10:26 AM   #10800
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Has anyone run in BMW CCA Club Racing. Eyeballing one of their races next year in the B Modified class. Curious what I would be getting myself into...
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      12-12-2019, 11:05 AM   #10801
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Originally Posted by OG Shark View Post
Has anyone run in BMW CCA Club Racing. Eyeballing one of their races next year in the B Modified class. Curious what I would be getting myself into...
Trying to do the school this year, but won't be doing any BMW CCA club racing. Maybe AER/WRL seats.
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      12-12-2019, 11:19 AM   #10802
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Has anyone run in BMW CCA Club Racing. Eyeballing one of their races next year in the B Modified class. Curious what I would be getting myself into...
I watched a BMWCCA club race at COTA while I was participating in an HPDE there the same weekend. Looked fun! That's all I have, hah.
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