Auto-x guys...suspension settings

Posted By: 70Cuda383

Auto-x guys...suspension settings - 04/07/11 09:53 PM

Question for you guys, what settings do you use for your front suspension to auto-cross? Caster, camber, toe-in, etc. I've got a reg cab Dakota w a hotchkis 2" drop up front, 3" drop in the rear. This is a weekend toy, that I plan to auto-x with, so I'm looking for a good handling set-up even if it sacrifices some tire longevity in the long run. It'll prob take me 10 years to put 15k miles on it!

Posted By: AndyF

Re: Auto-x guys...suspension settings - 04/07/11 10:48 PM

Not much toe, not much caster, as much negative camber as you can get and then some more.

Posted By: rabid scott

Re: Auto-x guys...suspension settings - 04/08/11 12:10 AM

Attached picture 6573753-alignment-specifications.jpg

Posted By: Magnum

Re: Auto-x guys...suspension settings - 04/08/11 01:10 AM

I agree with that chart 100%.

The only area you need to approach with caution is the -2.5 deg camber. This will turn like a real autocrossing machine but wide front tires are doomed with this setting on the street.

If it was strictly autocrossing, toe out.

Posted By: 70Cuda383

Re: Auto-x guys...suspension settings - 04/08/11 03:53 PM

Hmm...ok. maybe I'll compromise a tad then, despite the low mileage this truck will see, the miles it does see will be 90% street with maybe 4 or 5 auto cross events per summer.

Posted By: 70Cuda383

Re: Auto-x guys...suspension settings - 04/08/11 03:57 PM

and to help me better understand...what does each of these settings do?

for example, I understand how the camber works--tilt the wheels "out" so that when you go around a corner and the weight shifts, you actually end up planting the tire tread squarely to the pavement, maximizing latteral grip.

or at least...that's what I THINK camber is for!

toe in-out? why? does that affect the "turn radius" of each wheel as you turn the steering wheel? to give the outside wheel a straighter shot/less distance to travel? why wouldn't you want it to be 0 for reduced rolling resistance at ALL times?

caster -- isn't that where the upper control arm is moved forwards or backwards of the lower, to somewhat "rotate" the spindle that's holding the wheel...and what does that do for you...

Posted By: 70Cuda383

Re: Auto-x guys...suspension settings - 04/08/11 04:23 PM

Oh, another question, those specs, are they per side, as in, the relationship of the wheel to the frame? or wheel to wheel?

toe in for example... 1/16" so, is that 1/32" in on each side for a total of 1/16" or does the total between the 2 end up being 1/8" "off parallel"?

camber, 1 degree...is that 1/2 degree per side? or...?

Posted By: moper

Re: Auto-x guys...suspension settings - 04/08/11 04:49 PM

I like a little toe in, as much positive caster as can be gotten (not sure on a Dak but most mopars are limited there unless you change hard parts), and a little negative camber. Your setup will really determine the camber settings. The other two will work with almost anything.

Posted By: TC@HP2

Re: Auto-x guys...suspension settings - 04/08/11 05:15 PM

Quote:

and to help me better understand...what does each of these settings do?

for example, I understand how the camber works--tilt the wheels "out" so that when you go around a corner and the weight shifts, you actually end up planting the tire tread squarely to the pavement, maximizing latteral grip.

or at least...that's what I THINK camber is for!

toe in-out? why? does that affect the "turn radius" of each wheel as you turn the steering wheel? to give the outside wheel a straighter shot/less distance to travel? why wouldn't you want it to be 0 for reduced rolling resistance at ALL times?

caster -- isn't that where the upper control arm is moved forwards or backwards of the lower, to somewhat "rotate" the spindle that's holding the wheel...and what does that do for you...

Camber - you actually want the top of the tire "in" not out. This keeps the contact patch parellel to the ground as the body rolls around it. More body roll will require more camber.

Toe - direction stability on turn in. For a dedicated track car, I'd go toe out, but if this also see street driving, a very slight toe in would be prefered. At speed, the friction of the tires and slop in components tend to push them in to toe out by nature,so static toe in allows them to assume a natural zero when driving.

Caster-High speed stability and return to center behavior. Autocross is slow enough that the stability isn't a big deal, but return to center assistance can be nice.

The turn radius scenario you speak of in toe is actually called ackerman and not easily modified.

Ultimately, tire temps will tell you want settings the suspension wants. If you can borrow a laser temp gun, check the outer edges and center of the tire. Hotter areas need less of something, colder need more of something, until the temp is as even as possible across the tread. The drawback to this is ultimate track settings aren't necessairly ultimate street settings.

Posted By: AndyF

Re: Auto-x guys...suspension settings - 04/08/11 07:23 PM

Negative camber.

Attached picture 6575071-camber.jpg

Posted By: AndyF

Re: Auto-x guys...suspension settings - 04/08/11 07:24 PM

Camber spacers behind the knuckle help you get more camber.

Attached picture 6575075-AR324.jpg

Posted By: 70Cuda383

Re: Auto-x guys...suspension settings - 04/11/11 10:36 PM

ok...I'm back from the shop.

I got -1 degree camber on each side, 2.5 degrees of caster, and they set the toe by angle.

I asked for 1/16" toe in, the spit out on the sheet here shows -.32 and -.36 degrees per side, for a total cross toe of -.68, which is way MORE than the factory spec of .03 to .13 per side.

I thought I was asking them for less toe-in than factory? or does the factory settings not call for ANY toe-in?

I'm just worried that what I got is way more than what I asked for, looking at the factory spec vs what I asked for...

the truck is still there, I'm only 1 driver, have to wait for my wife to get home, but once it's home, and I measure, if the toe is a lot more, can I just adjust it out a bit on each tie rod end? or will adjusting that out throw off everything else too?

Posted By: 70Cuda383

Re: Auto-x guys...suspension settings - 04/11/11 10:40 PM

OH yea, and what a nice reminder of why I hate paying people to do work for me and much rather do it all myself!!

a "$70 alignment" turned into a $180 bill!!!

the $70 alignment, plus another $35 because of the extra time to get it to the specs I asked for instead of factory specs. ....um, ok, whatever.
I also asked for the wheels to be re-balanced, because when the truck ate a wheel bearing last weekend, it chewed up the inside of the rim, and I'm sure it affected wheel balance.

apparently that was another $40, because it takes him 30 minutes to balance 4 tires...oh and another $20 for "tape weight" instead of the clip on weights (which I did ask for)

when I break it all down, it seems somewhat fair, I can picture them going back and forth on setting trying to get the specs I asked for, which were greatly outside factory spec, and taking a bit more time, and 30 minutes to strip weights, spin the wheels, add weight, spin them again, etc. sounds fair to me, because I've done it a few times myself, but gosh...a $200 bill when I was expected $100!!

Posted By: autoxcuda

Re: Auto-x guys...suspension settings - 04/11/11 10:46 PM

Quote:

OH yea, and what a nice reminder of why I hate paying people to do work for me and much rather do it all myself!!

a "$70 alignment" turned into a $180 bill!!!

the $70 alignment, plus another $35 because of the extra time to get it to the specs I asked for instead of factory specs.

BS, IMHO !! if the car was way out of whack it would take just as long to get to factory specs.

Whats' will the toe? Just put it to the facotry spec of .03 Have them fix that. If they are going to charge you $35 for you "custom specs" then you should get what you asked for.

Do you know the factory spec range on the caster, camber, toe? Sometimes you are just in that same range just to one extreme end of it. So it is actually factory specs.

Posted By: 70Cuda383

Re: Auto-x guys...suspension settings - 04/11/11 11:13 PM

factory specs are:
-.1 to .9 degrees camber
2.5 to 3.5 degrees caster
.03 to .13 degrees toe-in

Posted By: autoxcuda

Re: Auto-x guys...suspension settings - 04/11/11 11:18 PM

Quote:

factory specs are:
-.1 to .9 degrees camber
2.5 to 3.5 degrees caster
.03 to .13 degrees toe-in

????? Then what was the $35 for!!

You did just ask for factory specs. What, you wanted 1.0 degrees of camber vs. .9 and that was $35 !?!?

Have them fix your toe to facotry specs.... Then don't go back and tell you friends.

Posted By: 70Cuda383

Re: Auto-x guys...suspension settings - 04/12/11 01:14 AM

I didn't mind him telling me that the specs were way out and they had to take extra time to get them dialed in, even if it was to specs that I provided instead of "factory"

afterall, the truck had a bent tie rod, ate a wheel bearing, and I just had the spindles completely off of both sides, changed the springs out to hotchkis 2" drop springs, messed with the tie rods to try to get it straight enough to drive back to an alignment shop...

my concern was what the heck is .6 degrees mean, and how does that translate to 1/16" toe-in... afterall, 1/16" toe-in would be different on a 26" tall tire than it would on a 29" tire, right?

obviously the degrees are the more accurate way to go.

Posted By: blown340

Re: Auto-x guys...suspension settings - 04/12/11 06:12 AM

Hotchkis has recommended alignment specs for those springs in the installation instructions.

Hotchkis instructions.

Their specs work really well!

-Jon

Attached picture 6581050-autoxdakm.jpg

Posted By: Hotchkis

Re: Auto-x guys...suspension settings - 04/15/11 04:52 AM

Quote:

Hotchkis has recommended alignment specs for those springs in the installation instructions.

Hotchkis instructions.

Their specs work really well!

-Jon

Jon,

Thanks for helping out! Nice looking Dakota!