AutoX: How much camber before you stopped shredding tires?

[CoryM]

Hey guys.

Just wondering how much negative camber it takes to keep the outside edge alive on these cars? I'm currently running just shy of -3° up front and my winter autoX tires are almost bald on the outside, and (I kid you not) the nubs are still on the inside edge :eek:. I'm running HS, high tire press, stock springs, TRD rear ARB.

Also, how are you guys getting more neg camber? I'm maxed out using crash bolts. Tempted to forget about PAX times and classes and just run whatever I run.

Thanks.
Cory

[Viperoni]

Your issue is spring rate, not camber.
Any more camber and you'll begin to lose acceleration & braking traction (if you aren't already).

[xnamerxx]

Depends on a lot of things. If you're riding the bumpstops you'll never get enough camber to fix the issue.

Details of everything tires ect? I've run my car up to -4.7 camber depending on the tires I run.

[ilikerice]

What kind of tires are you running? What size.. could be your side walls are not strong enough with all the cornering that comes with autox even with the high pressure you are running.

I have this issue with my OEM steelies and the 195/60 cheap tires when I daily drive it. I run -3 in the front also. But my 195/50 on my 15x7.5 rim seems to wear evenly as my daily driver and I have about 40psi all around on those

I run STF so my track setup is 225/45 on 15x7, and I normally run Hankook RS3, but I just recently got the Toyo R1R in the front and the RS3 in the back and run about 30psi inthe front and 55psi in the rear. (thats my driving syle, everyone is different)

[CrankyOldMan]

My experience with outside shoulder wear is that it's all about corner entry speed. If you're overdriving it, you're going to chew up your sidewalls in a hurry. My other solution is to run the fronts as high as I can -- upwards of 50 psi hot-- and drop the rears to get more rotation. Keep in mind these are 205/50 Rivals on 15x7's, with about -15° camber on OEM crash bolts, so your mileage may vary. Oh, I've also got a Blitz, so I'm pushing a lot harder coming out of the corners, too.

[ilikerice]

Dropping pressure in the rear and that much pessure up front will cause alot of understeer. I have mine high in the back to increase rotation. If you drop pressure in the back you wont be able to rotate the back as easily as you would with higher psi

[CrankyOldMan]

Hmm, it could just be my technique then. Even dropping a few lbs up front causes some significant sidewall creep. Perhaps I need to adjust my cornering instead of air pressure?

[xnamerxx]

Rivals do that, I needed 4.7 degrees to keep the Rivals from rolling over. Check to make sure you aren't riding the bump stops. Once you do that your only spring is effectively the tire which will only deflect and rollover. Rivals are generally pretty resistant to tire pressure change, I typically ran them in the 35-38 range.

[cali yaris]

I would never run more than -3 on the fronts. Spring rates, damper specs and sway bars are all in play; make adjustments there.

Trying to "fix it" with more camber is a poor strategy that won't get the desired result.

[xnamerxx]

The National STX and STC guys typically run in the -4.1 range.
Your not only fighting body roll but your also fighting tire deflection. Tire deflection plays a big part it the amount of camber needed. Running 225 tires on a 7" wheel results in lots of tire deflection and needs quite a bit of camber.

[CrankyOldMan]

Am I the only one that has noticed that the OP hasn't responded to our comments? =)

[CoryM]

Sorry for the late reply.

I guess my situation is a little unusual. The Yaris is just my daily driver, that sees winter autoX duty (mostly). I always intended to stay in stock class because it limits how much money I can spend on the car and be legal (and its PAX is good). Now that I am looking at my tires, and the rules are changing, I may change classes. The problem (and I use that word tongue-in-cheek) is that I get one set of NT01s every spring for very cheap. So I use them as my summer tires, and autoX tires when warm enough. There really isn't much to be done before getting kicking into Street-Prepared(?) while running on the R-comps.

So tire pressures:

-205/50R15 NT01 on 15x5.5 (skinny rims but required for Stock) 51/41
-205/50R15 NT01 on 15x6.5 (summer daily drivers) 46/36
-195/55R15 Kumho Ecsta 4X on 15x5.5 (autoX tires when below 10°C. Comparable to Conti DWS) 51/41

Car is stock except for -3° camber up front and TRD rear bar. Ordering Tokico blues soon as I need struts anyhow. To reduce the roll (and camber loss) I was considering trying a front swaybar to keep me legal for Stock, and just adjust rear pressures until I get some oversteer back. The car's understeer is currently reasonable, although inside tire spin is always a fight.

Ignoring classes, really all I would consider replacing are things like:
-F swaybar
-Springs, but don't want to be canned. There are enough dips at autoX to need suspension never mind street use.
-hub spacers (creates more understeer though right?)
-?

Coil-overs are out. I'd sooner have an LSD for that much $$$ and I just can't justify it on the Yaris.

My driving, while somewhat inconsistent, is probably fairly reasonable in terms of tire wear. I certainly know enough to slow down when scrubbing. Probably my worst trait is upsetting the car on braking but that just kills cones, not tires :laugh:

Thanks for the input.

[CoryM]

Am I the only one that has noticed that the OP hasn't responded to our comments? =)

I was responding as you posted that :tongue:

[cali yaris]

Your not only fighting body roll but your also fighting tire deflection. Tire deflection plays a big part it the amount of camber needed. Running 225 tires on a 7" wheel results in lots of tire deflection and needs quite a bit of camber.

Exactly my point. Those tires require a larger wheel, so you're compensating for a mistake. Same with the body roll. Fix it the right way and you don't need that much camber.

We are going to have varying opinions on this, I base mine on my racing experience and my conversations with others on and off the track.