Autocross tire pressure help

[MonkeyMD]

That is super tight. My car would hate that. If probably be in 1st for a lot of it.

Do you guys have to spray your rear tires. Seems like mine never get hot enough to require it. Maybe after 5 runs if we're doing 6, but even then.

 

[krs]

So far this season I haven't needed to spray the rears hardly at all. During this event there was a long delay between runs, and the fronts started to cool down so I tried not spraying, which was a mistake and they got greasy. We'll see how I do tomorrow.

Unless it’s in the 60°’s or less, I start spraying after my second run on the fronts, pretty much all the time. If I wait until they get real hot to the touch, then I’m battling the internal tire and rim temps. Anything I can do to slow that down I will. At least that’s my theory.

Then of course if it’s 100°+ out, good luck. Better make that first run count.

 

[GTIfan99]

That event also resulted in this on the right front tire. The tires didn't show signs of rubbing in two prior events. Both left and right fender screws were polished, so I did the fender screw mod today. The scoring on the tire seems too far inboard to be caused by the fender screw, so I don't know what caused this.

View attachment 253814



View attachment 253815

It was caused by 32 psi.

 

[bfury5]

-3.3 front camber, 400 pound springs, 28mm front sway, I still need 41psi start pressure with RT660's to not roll over. Anyone doing it with less air pressure has some very stiff springs or drives slow.

what size wheel and tire? that's a good amount of camber and pressure, surprised it takes that much to not get rollover

 

[GTIfan99]

I normally allow more rollover than that.

I'm finding, depending on 200tw tires you're using, and size, you need 36 to 40 psi.

I too came from a Miata running 26 psi. You just can't do it in a GTI or R. You need more pressure or you'll chew up the tires or create understeer.

 

[bfury5]

18s 8 inch wide rim, rt660 235/40…8.5 wide rims would help some, but I do rub slightly on inside if turned to max. I could do with smig less camber. I push the car HARD, send it and my local corse is a fast old runway. Not a parking lot club. I race the 23rd of July, will post a video.

You should have seen the Yokohama’s a052 I ran, chewed crap out those sidewalls!

There ya go. 7 days Autocross. Flipped on rim after 4. Maybe 8 events…I lost count.

I also pushed my car hard. That wear looks reasonable, I don't see anything off with that. I do not believe less camber is the answer here, especially on these cars. Also surprised you're rubbing with only 235s in the front. An 8.5" wide rim would definitely help, but those don't look chewed up to me.

 

[GTIfan99]

That looks like pressure is too high.

It is.

 

[GTIfan99]

How so?

You see that Triangle marker? Not supposed to get wear past that. If I use less air pressure it get further into it and Beyond.

This conversation is getting kinda old. You do you boo. I’m happy with my results.

GRM has done some fantastic testing over the years. For autocross, to get maximum grip, you'll want it a little lower than that.

And you sound like an asshole getting defensive when people try to give you information. I've been autocrossing for 35 years, you have too much pressure for autocross, about right for tracking, but you aren't even to the tip of the pointer.

So either maybe listen to people that have been doing this for a long time or don't ask questions if you know you already have the answer you want from your vast experience.

 

[deleteaccount]

GRM has done some fantastic testing over the years. For autocross, to get maximum grip, you'll want it a little lower than that.

And you sound like an asshole getting defensive when people try to give you information. I've been autocrossing for 35 years, you have too much pressure for autocross, about right for tracking, but you aren't even to the tip of the pointer.

So either maybe listen to people that have been doing this for a long time or don't ask questions if you know you already have the answer you want from your vast experience.

You know more then the tire manufacture? I removed my posts because my car is much different and tire pressure can vary a lot depending on set up. I read dam near ALL of your old posts. Your not as knowledgeable as you claim. In fact I'm done with this forum because its a fan boy club of fools like you.

 

[deleteaccount]

You know more then the tire manufacture? I removed my posts because my car is much different and tire pressure can vary a lot depending on set up. I read dam near ALL of your old posts. Your not as knowledgeable as you claim. In fact I'm done with this forum because its a fan boy club of fools like you. And keep laughing dude, your set up is shit!

 

[GTIfan99]

You know more then the tire manufacture? I removed my posts because my car is much different and tire pressure can vary a lot depending on set up. I read dam near ALL of your old posts. Your not as knowledgeable as you claim. In fact I'm done with this forum because its a fan boy club of fools like you.

Oh no, don't leave...

Jk, no one cares. You don't have to announce when you leave.

I rely on guys like Mike King, Andy Hollis and several other of the national champions in our area that do extensive tire testing. Andy shares his tire testing in GRM articles about twice a year.

They literally skid pad test at several different pressures and measure lateral grip.

I'm smart enough to listen to the aliens. I'm just sharing the info with you.

 

[GTIfan99]

You can't even figure out how to post an insult correctly.

My setup is fast, so don't really care if you like it or not.

 

[deleteaccount]

You can't even figure out how to post an insult correctly.

My setup is fast, so don't really care if you like it or not.

You are a forum fool. Who cares who you listen too. Your set up is TRASH! It's obvious reading your trash posts. 50 years old with 35 years! ROFL! I WOULD WIPE THE FLOOR WITH YOU!

 

[GTIfan99]

You are a forum fool. Who cares who you listen too. Your set up is TRASH! It's obvious reading your trash posts. 50 years old with 35 years! ROFL! I WOULD WIPE THE FLOOR WITH YOU!

I thought you were leaving?

I started when I was 15, my parents both autocrossed and road raced. Are you unable to do simple math?

 

[deleteaccount]

I thought you were leaving?

I started when I was 15, my parents both autocrossed and road raced. Are you unable to do simple math?

I am. When I’m done mopping the floor with you. 15 years old when you started…35 years of experience and still a fool, 50 years old. Did I miss something?