034 RSB, tire pressure, and traction control settings - looking for advice

[Waltari]

Always hot pressures.

Again, the wear bar is just an indicator of wear, not an indicator of grip.

Also (kinda rambling now) but sometimes you can get wear that is misleading. I was at 33psi cold at Laguna Seca this weekend and noticed some wear on the shoulder of the tire, indicating too low of pressure. I was confused as it was about 75F out and I was driving quite hard so if anything 33psi should be on the high side of ideal. But check out the deflection of the tire in this photo. Huge compression zones like at the bottom of the corkscrew can inflict some unusual wear on a tire that is otherwise the correct psi. Reiterating my last point, I think you just have to go on a case by case basis.

View attachment 211002

I think these photos by @Will_ are just fine, if you want to go by wear.

There is no reason to lower pressure to "make sure the wear goes down to the wear bar".

Think of the wear bar as a limit, not a goal.

Always hot pressures.

Again, the wear bar is just an indicator of wear, not an indicator of grip.

I think these photos by @Will_ are just fine, if you want to go by wear.

There is no reason to lower pressure to "make sure the wear goes down to the wear bar".

Think of the wear bar as a limit, not a goal.

My wear is about in between the first and second photos Will shared. Definitely no situations like the Laguna Cork Screw at PIR...it's a 1.967mile track, with 12 turns and virtually no elevation change.

 

[spaparizos]

Always hot pressures.

Again, the wear bar is just an indicator of wear, not an indicator of grip.

How do we figure out the grip then? Any good tricks to use? Is it sustainable G numbers from data logging?

I am aware of the wear triangles or measuring the tire temps in,middle, out as suggestions. But good to hear of other ways one can look into this.

A comment, tire dimensions and air play a role in the PSI needed to support the same weight. Size 225-40-18 like stock need 2-3 PSI higher than 235-40-18 to support the same weight at XL rating. Of course tire construction and sidewall stiffness and XL vs SL ratings affect things.

 

[xXDavidCXx]

How do we figure out the grip then? Any good tricks to use? Is it sustainable G numbers from data logging?

I am aware of the wear triangles or measuring the tire temps in,middle, out as suggestions. But good to hear of other ways one can look into this.

A comment, tire dimensions and air play a role in the PSI needed to support the same weight. Size 225-40-18 like stock need 2-3 PSI higher than 235-40-18 to support the same weight at XL rating. Of course tire construction and sidewall stiffness and XL vs SL ratings affect things.

Testing, traction circle, maybe logs, stop watch, feel.

When I had -2.0 front camber and pressures 30-35, at autocross the front just plowed as soon as I applied the brakes for a turn and then tried to turn. As soon as the tires were loaded from braking they could not take any other input.

Eventually I tried up to 40-44 front PSI and combined with rear toe-out transformed the car.

 

[Will_]

I think we should probably make the distinction between tire pressures for Autocross versus track use. I was taught for Autocross to start with 5 PSI above cold to start and adjust from there, so I would use 40 PSI cold, whereas for track use it was the opposite advice - bleed down around 5 PSI as a starting point.

 

[xXDavidCXx]

I think we should probably make the distinction between tire pressures for Autocross versus track use. I was taught for Autocross to start with 5 PSI above cold to start and adjust from there, so I would use 40 PSI cold, whereas for track use it was the opposite advice - bleed down around 5 PSI as a starting point.

Sure.

But I'm speaking in hot pressures, so how you get there with a cold tire setting is irrelevant.

 

[SouthFL_Mk7.5]

I’ve used between 34-36psi cold on my GTI on the few track days I’ve run (with this car) with success.

 

[tpellegr]

Only way to be 100% certain you are using the proper pressures for the conditions is by using a tire pyrometer. Outside of that, I would say wear observations are likely the next most objective. Optimum hot temps vary by tire, but @Will_'s shared some really good advice as a starting point.

Lap times and feel likely not good indicators unless you are putting down extremely consistent lap times or are a very experienced track driver.

 

[xXDavidCXx]

Only way to be 100% certain you are using the proper pressures for the conditions is by using a tire pyrometer. Outside of that, I would say wear observations are likely the next most objective. Optimum hot temps vary by tire, but @Will_'s shared some really good advice as a starting point.

Lap times and feel likely not good indicators unless you are putting down extremely consistent lap times or are a very experienced track driver.

Dude, tell me the 100% for sure method by using a pyrometer, and link the results to what exactly the car needs.

I'll wait.....

I've used all these methods, but the only thing that actually helped me get to a solution was analysis and testing.

Not just a pyrometer, because the temps said my tires were too hot in the center, so maybe I should reduce the pressure. So I reduce front pressure and my problem got worse. The issue was actually not enough front camber.

Take in all the data, it will lie to you if you don't have a full understanding why you are getting specific results.

 

[tpellegr]

David, I'm not sure what issue you were having, but if a pyrometer is reading higher temps in the middle of one's tire than the edges, the tire is overinflated. I would recommend doing a bit of research or buying yourself a book on the topic if you are having a hard time understanding. Happy to recommend a few if you'd like to DM me.

Edit: Also, I would stop assuming that your autocross experience qualifies you to make recommendations to beginner track drivers. As you know, autox and HPDE are two very different operating conditions and require very different setups. Your observations based on 50 second autox runs are not necessarily going to be relevant to someone looking for setup advice for a 20-25 minute session on a road course. I'm trying to provide some basic guidelines and rules of thumb to help guide people into finding a setup that works for them. I'm sorry if you have a problem with that.

 

[xXDavidCXx]

David, I'm not sure what issue you were having, but if a pyrometer is reading higher temps in the middle of your tire than the edges, your tire was overinflated. I would recommend doing a bit of research or buying yourself a book on the topic if you are having a hard time understanding. Happy to recommend a few if you'd like to DM me.

Edit: Also, I would stop assuming that your autocross experience qualifies you to make recommendations to beginner track drivers. As you know, autox and HPDE are two very different operating conditions and require very different setups. Your observations based on 50 second autox runs are not necessarily going to be relevant to someone looking for setup advice for a 20-25 minute session on a road course. I'm trying to provide some basic guidelines and rules of thumb to help guide people into finding a setup that works for them. I'm sorry if you have a problem with that.

I don’t need your help with my car setup and I have all the data to backup my analysis. No, it was not an over inflation issue.

My car drives fantastic now, and my autocross times prove it.

We will have to agree to disagree.

 

[tpellegr]

I don’t need your help with my car setup and I have all the data to backup my analysis. No, it was not an over inflation issue.

My car drives fantastic now, and my autocross times prove it.

We will have to agree to disagree.

I never commented on your setup, just the tools we have to help us guage whether tires are operating within their optimal temp range (which was the OP's question). Although imperfect, a good tire pressure guage, pyrometer, and observing the wear on the tire itself are as good as it gets (unless we want to have an expert like you sit shotgun with us every session to share your advice on how the car feels). Glad to hear you are happy with your lap times. I'm sure they are great!

 

[Waltari]

David, I'm not sure what issue you were having, but if a pyrometer is reading higher temps in the middle of your tire than the edges, your tire was overinflated. I would recommend doing a bit of research or buying yourself a book on the topic if you are having a hard time understanding. Happy to recommend a few if you'd like to DM me.

Edit: Also, I would stop assuming that your autocross experience qualifies you to make recommendations to beginner track drivers. As you know, autox and HPDE are two very different operating conditions and require very different setups. Your observations based on 50 second autox runs are not necessarily going to be relevant to someone looking for setup advice for a 20-25 minute session on a road course. I'm trying to provide some basic guidelines and rules of thumb to help guide people into finding a setup that works for them. I'm sorry if you have a problem with that.

Thanks guys...not wanting to have this hijacked into a argument between different types of setups for different types of events. I do appreciate the input and am definitely focusing on track days and not Autox. Here's a video for reference showing our track out here at Portland International Raceway during my last session about a week back.

Admittedly, I got a little aggressive mid session and hit the rev limiter, but otherwise the first time out for the spring felt pretty decent. Mainly looking to dial things in to help keep everything planted, good traction, and get quicker through the corners.

 

[tpellegr]

Thanks guys...not wanting to have this hijacked into a argument between different types of setups for different types of events. I do appreciate the input and am definitely focusing on track days and not Autox. Here's a video for reference showing our track out here at Portland International Raceway during my last session about a week back.

Admittedly, I got a little aggressive mid session and hit the rev limiter, but otherwise the first time out for the spring felt pretty decent. Mainly looking to dial things in to help keep everything planted, good traction, and get quicker through the corners.

Looks like an awesome track! Thanks for posting and sorry to drag things off topic.

 

[xXDavidCXx]

I never commented on your setup, just the tools we have to help us guage whether tires are operating within their optimal temp range (which was the OP's question). Although imperfect, a good tire pressure guage, pyrometer, and observing the wear on the tire itself are as good as it gets

You literally told me my tires were over inflated.

Tire temps only work as a tool when the tire is optimized, not in a camber limited stock setup.

Not sure why you are so resistant to factual, data based analysis.

 

[Waltari]

Looks like an awesome track! Thanks for posting and sorry to drag things off topic.

No worries and yes, definitely a fun track. Next track day is about 2 weeks out!