Thanks! Feel a lot better now.

 

Almost the same as my new alignment by Cobb Plano. Everything works harmoniously better, the lowering springs,rsbar and wider tires.

Front L/R -1.8 Camber
Rear L/R-1.5 Camber
Toe 0/0

 

Here are a few things I have learned about alignment:

Camber:
Negative front camber will increase traction and turn in response, which tends towards oversteer.
Negative rear camber will increase traction at the rear, thus increasing understeer.
The front and rear have to find that harmonious balance to go through the corner with neutral balance and no scrubbing of speed.

Toe:
First some people refer to toe in and toe out differently when it comes to numeric settings. For me, Positive Toe = Toe-In, Negative Toe = Toe Out.

Toe and cornering:
Toe out on the rear the car will tend towards oversteer. This is because the outside, more heavily loaded tire (the tire with the most influence on cornering) is pointing towards the outside of the corner. This steers the rear outward and brings the back end out relative to the front. So rear toe out helps initial turn in and hurts in the straights and throttle-on corner exit. A slight amount of rear toe-in will make the car more stable and will promote a slight amount of "understeer" when running at the cornering limits.

Now think of that toe out situation on the front, and you see that toe out steers the front towards the outside of the corner. This equals understeer which you want to avoid on a road course or autocross track.

Some people use toe out, whether they think it or not, to stabilize the car (understeer). In autocrossing, the car is usually never completely steady state, and the understeer at the front makes it more forgiving. If people run toe out at the rear, this destabilizes the car. Then they dial in front toe out to compensate, whether they think it or not, for the instability.

Toe and straight line driving:
Toe in will stabilize the car in straight line driving and reduce "torque steer" on acceleration, but create a little scrubbing and reduce speed. Toe out on the straight will cause the car to wander and create a little scrubbing and reduce speed. Zero toe will optimize speed on the straights.

Toe under static and dynamic load:
Your dynamic toe, or toe while you are moving or accelerating, will be more “outward” than your static toe, or toe as the car sits on the alignment machine (the toe becomes a less positive number or a more negative number). Why? A few reasons;
a) due to bearing and bushing compliance;
b) it is not uncommon for the camber to slip in the positive direction at the clevis bracket due to cornering loads (make sure you torque the clevis bolts!) When the camber setting goes positive, your toe goes out;
c) during periods of acceleration (especially down a straightaway) your front wheels will lose negative camber and, as just mentioned, move the toe in the outward direction as the weight comes off the front (watch the front tires of a dragster as it comes off the line).

So if you start toed out statically, you get more toe out. If you start toed in, you go toward zero and even to some toe out.

Front toe:
Adding a small amount of additional "static" toe-out in front will encourage slightly better steering response when entering a high speed corner. Being that most autocross courses are almost all corners and slaloms, adding some additional front toe-out will usually increase speed. The downside of running more front toe is the tire scrubbing and drag created in the straight-aways will decrease speed. However autocrosses are rarely about straights, so more front toe might be okay. But for daily driving and road racing, more front toe will wear out tires and make straight-aways “wiggly”.


Rear toe:
Adding rear toe-out helps the loaded outside tire turn the back end of the car, which can be very advantageous in the many tight corners and slaloms seen on a typical autocross course ... but can be very unnerving and in fact dangerous on a street car because it encourages "oversteer". A car that wants to spin when driven at its limits is not good on the street, especially in the rain or snow.

Of course all this alignment talk assumes the settings are a part of a completely matched suspension set up including stiffness of struts (especially adjustable) the type of pavement (smoothness, grip, etc), the size and stiffness of the sway bar.

 

One part I disagree with: that front toe-out causes understeer (at least, at autocrossing speeds). It actually helps rotate the car after turn-in, which many of us know from experience, and here's the why:

when you're in a turn, the majority of the weight is on the outside wheels, so they have more grip. So think of the nose of the car as traveling mostly in the direction set by the outside front. If you have a lot of front toe-out, then the inside front is pointing too far to the inside. To the extent that it has grip and you have AWD (as we do), any power put down by the inside front pulls the nose inwards even more. To the extent that the inside front is just scrubbing (such as coasting in the turn or any RWD car), it is dragging on the inside front, so that also helps rotate the car.

Note: front toe-out (on a nose-heavy car) is the best way to kill a set of tires in a short period of time. This is not something that you do to a DD that you autocross six times a year. This is something you do to your trailer-queen.

 

Great points – there is no one perfect set up, especially as I noted this summary was without any consideration for struts, pavement, sway bars or the rest of the suspension set up. Opinions and disagreements need to be aired to get a variety of views on here that will help folks apply the ideas that are most analogous to their car.

I do scratch my head when you say the greatest weight is on the outside wheels so they have more grip, but go on to say AWD power will help the inside wheel pull through the corner. I do agree that front drive power will pull the nose inward due to the inside wheel pointing too far to the inside, but similarly the outside wheel is pointed too far to the outside, and if it has the greater weight, then relatively speaking should it not have the greater influence on the direction the car wants to go?

 

You missed the part where I said that the nose of the car is mostly going in the direction of the outside wheel. So, the outside front is not pointing to the outside; it's pointing in the direction of travel. All of the front toe-out is, in effect, ending up on the inside front, causing it to pull your around, if powered, or drag you around, if not powered.

 

I agree that is what is happening with the inside wheel. But on a hard turn the inside wheel has less influence and traction because it is lifting/unloading and the weight load and traction shifts to the outside wheel. The greatest influence on the direction of the front end is going to be the tire with the most traction, which is the outside wheel. If the outside wheel is toed in, it will tend to pull the car into the turn more (because it is point more into the turn) than if it is toed out.

 

Think about it this way: what does the ASC do when it detect understeer? It applies the brakes to the inside front. Well, scrubbing the inside front does the same thing.

Now, I suppose that you could argue that I'm applying pre-fancy-ASC thinking to a problem that has been roughly solved by ASC. And I should admit that I'm not so serious any more and don't run any front toe-out just to save a few hundred milliseconds every other summer weekend. But that's still the logic behind front toe-out to rotate a car.

 

Great info!!!

 

Would more negative camber cause quicker wear on the tires? Or is it just toe being off 0 that determines faster wear?

 

The easiest way to think about it (which also happens to be mostly accurate) is that toe determines the amount of wear and camber determines where is happens. So more camber will mostly focus the wear on a smaller proportion of the tread.

 

Good job! well done

 

Really well put together, even a newbie like me understood what was said.... thx

 

Thanks for a useful information!

 

Hey guys im new to the forum and wondering if anyone can help. I have a 13 evo with the handling package and my tires are having really bad cupping and inner wall wear, i bought cam bolts for the front but it only gives me more negative camber, any ideas?