Track forum general chit chat.

[Kelse92]

Originally Posted by rhyary

Some tires and camber conclusions from my 2019 and projections to 2020.

If you followed my posts here, you know I went through lots of configurations, much to the chagrin of forum members. Here are some learning lessons and implications to the 2020 season. Advice and comments are welcomed.

The season was mostly done using -3.0 front camber and -2.0 on the rear. I don't have useful info on the rear. It was on constant 295/30/19 with all tires experiments

The front saw four sizes
235/35/19 slick RR
265/35/19 slick R7
265/30/19 100/200 type tires R888R, ADOR8, PS4S
275/30/19 road/rain tires (say PS4S or similar)

Some of the above are more 2017-18. Of interest in 2019 are two sizes - 235 and 265 /35

I’m sure you’ve mentioned this before but I probably missed it. Why not testing 18’s at all??

[rhyary]

Originally Posted by b4hand

So an r7 would only last a 2 day track weekend? Damn

Typically this is how I finish the second day:
.

[rhyary]

Originally Posted by Kelse92

I’m sure you’ve mentioned this before but I probably missed it. Why not testing 18’s at all??

Yes, the 18" 19" has been covered extensively.
In short, 18" won't clear my Brembo brakes

[dogbone]

Originally Posted by rhyary

Yes, the 18" 19" has been covered extensively.
In short, 18" won't clear my Brembo brakes

Wait....is that an F8x M3 hub? Are you on 14mm studs?

[Bartledoo]

So you're going to be running RR's 295 rear and 235 front? On an M3?!

[rhyary]

Originally Posted by Bartledoo

So you're going to be running RR's 295 rear and 235 front? On an M3?!

Yap, fastest and cheapest combination after the R7 set. Another way to think about the delta between 1:37.2 and 1:35.7 is $600 of tires.

That is the cost of two track days for less than 2 second.

I have to admit that the grip of front R7 265/35/19 is intoxicating.

BTW, while 235 sounds narrow, I calculated width of rubber on the road of 245, 265, and 275 and everything I measured had LESS contact patch than the RR 235. And the data backs it up.

[OG Shark]

Originally Posted by dogbone

Wait....is that an F8x M3 hub? Are you on 14mm studs?

https://ind-distribution.com/collect...b-retrofit-kit

[dogbone]

Originally Posted by OG Shark

https://ind-distribution.com/collect...b-retrofit-kit

Ah ok. The Future Classic setup. Nice. When did you move over to that?

[roastbeef]

Originally Posted by rhyary

I have to admit that the grip of front R7 265/35/19 is intoxicating.

BTW, while 235 sounds narrow, I calculated width of rubber on the road of 245, 265, and 275 and everything I measured had LESS contact patch than the RR 235. And the data backs it up.

these statements essentially contradict each other.

more grip with a 265, but somehow the 235 has a larger contact patch? contact is directly related to grip.

[tsk94]

Originally Posted by roastbeef

these statements essentially contradict each other.

more grip with a 265, but somehow the 235 has a larger contact patch? contact is directly related to grip.

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.

[roastbeef]

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.

[gmx]

Initially, I also refrained from commenting. Maybe rhyary is giving us the tl;dr of his notes?

Different compounds and different tyres are going to require different alignments. I have no idea which "265" is being compared here:

The 265 coded the OUTSIDE after 10 x 20 sessions.

both tires on -3.0 could not finish two days on pace.

If that was feedback on PS4S, I wouldn't be surprised. It's an elite road tyre that has no place on a dry track unless you keep a razor sharp eye on temps/pressures plus, drive below the limit with sympathy for the tyre .
AD08Rs have steel inserts and should cope decently with camber. I ran them at -2.8 on soft OEM suspension (1M being softer I suppose?) and same set once at -3.4 with coilovers (570lbs/in). If you corded (or wore/tore?) the A7/R7, needs more camber! A probe pyro would tell you this immediately.

[Bartledoo]

Regardless of his contact patch calculations and comparisons of wide x brand tires to the 235 RR, he said he was running 295 rear RR and 235 front RR. I can't imagine that M3, with its relatively typical overall track setup, not handling like crap and understeering horribly.

[rhyary]

Originally Posted by dogbone

Wait....is that an F8x M3 hub? Are you on 14mm studs?

I am. Front and Rear. MSI

[rhyary]

Originally Posted by roastbeef

these statements essentially contradict each other.

more grip with a 265, but somehow the 235 has a larger contact patch? contact is directly related to grip.

with the exception of the R7 which is also slick

[rhyary]

Originally Posted by roastbeef

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 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.

[rhyary]

Originally Posted by gmx

Initially, I also refrained from commenting. Maybe rhyary is giving us the tl;dr of his notes?

Different compounds and different tyres are going to require different alignments. I have no idea which "265" is being compared here:

If that was feedback on PS4S, I wouldn't be surprised. It's an elite road tyre that has no place on a dry track unless you keep a razor sharp eye on temps/pressures plus, drive below the limit with sympathy for the tyre .
AD08Rs have steel inserts and should cope decently with camber. I ran them at -2.8 on soft OEM suspension (1M being softer I suppose?) and same set once at -3.4 with coilovers (570lbs/in). If you corded (or wore/tore?) the A7/R7, needs more camber! A probe pyro would tell you this immediately.

I thought I was clear that it was between two slicks, RR and R7

[rhyary]

Originally Posted by gmx

Initially, I also refrained from commenting. Maybe rhyary is giving us the tl;dr of his notes?

Different compounds and different tyres are going to require different alignments. I have no idea which "265" is being compared here:

If that was feedback on PS4S, I wouldn't be surprised. It's an elite road tyre that has no place on a dry track unless you keep a razor sharp eye on temps/pressures plus, drive below the limit with sympathy for the tyre .
AD08Rs have steel inserts and should cope decently with camber. I ran them at -2.8 on soft OEM suspension (1M being softer I suppose?) and same set once at -3.4 with coilovers (570lbs/in). If you corded (or wore/tore?) the A7/R7, needs more camber! A probe pyro would tell you this immediately.

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

[rhyary]

Originally Posted by Bartledoo

Regardless of his contact patch calculations and comparisons of wide x brand tires to the 235 RR, he said he was running 295 rear RR and 235 front RR. I can't imagine that M3, with its relatively typical overall track setup, not handling like crap and understeering horribly.

Well, perhaps on paper 235 295 understeer like crazy, but it does not. I somewhat understeer but it is manageable.

The only combination that got me into 1:37 besides RR and R7 is the ADO8R when I was on 265/30/19 front. At that time, I was afraid that 265/35/19 won't fit. But @slicer posts and others convinced me to try the R7 size ls to 265/35/19. It worked ver well.

I liked the ADOR8 the most on the track out of the non slicks.

I love the PS4S 275/30/19 on the road and in the wet on the track.

So a viable non-slick option is the ADO8R in 265/35/19 295/30/19. The the price is almost like the R7, so for the price, I rather get the R7. But I am very curious to give that combination a try.

The RR is not ideal, but factoring the RR price of less than $1000 for a set, and $237 front is very compelling option. And fast.

The RR rears last many track days (so was the R7)

So I rather experiment with the RR since it is the lowest price for almost fastest time.

Last comment about the PS4S. While wonderful tire in the wet and damp surface, in the dry at a 1:38 pace I am peeling the rubber of the tire. So not just wear, but the rubber is too soft.

The ADO8R where impressive at 1:38/37 pace but again I was on -2.5 when I tried them and corded the outside.

In general, I think it is good to be skeptical of anyones findings. At the same time, I have close to 70 track days on the same track, and I am running one of the fastest times on that track given HP and weight. So perhaps it means something. Or not. Who knows.

[PrimeBMW]

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.

[rhyary]

Originally Posted by PrimeBMW

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?

[tsk94]

Originally Posted by rhyary

I thought I was clear that it was between two slicks, RR and R7

Originally Posted by rhyary

with the exception of the R7 which is also slick

Originally Posted by tsk94

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.

Originally Posted by roastbeef

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!