[Blurv100]

What do you think works best for rear toe? I'm going to try zero front but what does anybody recommend for the back?

[bronxbomber252]

Blurv100, on Mar 7 2010, 08:17 PM, said:

What do you think works best for rear toe? I'm going to try zero front but what does anybody recommend for the back?

In general up front you want 0 or a little out.

Rear toe is car dependent. In my car, which is very tail happy, a bit of toe in balances out the handling nicely, in other cars, that push more, toe out helps the car rotate. What kind of car do you have? and hoe does it handle?

[Blurv100]

Hey Brian- It's me- Joe- with the focus.

Well focii have a flukey passive rear steer setup that toes the wheel in as the suspension compresses, and still they're calling for .04" per side in the back to start with. So maybe a little toe-out wouldn't hurt.

[bronxbomber252]

in a Front wheel drive car it can help. in general, toe in increases understeer and rear end stability, while toe out has an oposite effect. Toe out will help the car rotate better if you are finding it to push too much. BTW, most cars with independent suspension have toe angles change as the suspension compresses and decompresses.

[JoeCool]

Blurv100, on Mar 7 2010, 08:17 PM, said:

What do you think works best for rear toe? I'm going to try zero front but what does anybody recommend for the back?

I disagree a little with Bryan. On a FWD car I would go with zero rear static toe or slight toe in (1/16th inch or less total toe). Static toe out creates an unstable condition. I would use rear bump steer to create the rear steer effect. Start with 1/16th inch toe out per inch of suspension bump travel. You may need some kind of bump steer kit to accomplish this movement. The net effect would be when you turn the front wheels one way the rear tires turn the opposite direction. This allows both sets of tires to travel in a similar circle. Toe in causes the rear tire to steer in the opposite direction of the front. Not good.

RWD cars use some rear toe in to compensate for toe out created when car accelerates. Rear steer can be designed into solid rear axle cars as well (Hint Hint solid rear people). This is done by changing the angles of the lower control arms.

[evremonde]

Whats the effect on tire wear of having 0 toe? I tried to get the rear wheels set to zero toe, and the tech at the shop was adamant that i would be back in a few thousand miles needing new tires.

From researching it seemed that 0 toe for the rear was a good way to get some oversteer.

[JoeCool]

evremonde, on Mar 16 2010, 10:53 AM, said:

Whats the effect on tire wear of having 0 toe? I tried to get the rear wheels set to zero toe, and the tech at the shop was adamant that i would be back in a few thousand miles needing new tires.

From researching it seemed that 0 toe for the rear was a good way to get some oversteer.

What the tech is referring to is that zero static toe will actually give you a slight toe out at highway speed. This happens because of all the compliance in the suspension components. The more toe out you have at speed, the more tire wear you will have. The manual probably calls for static toe in giving you close to zero toe at highway speed.

This is why I recommended handling rear steer with bump steer not static toe out. You can go with stock toe setting this way and if you are lucky there is some stock bump steer built in already. Keep in mind this will only help a little. All cars that are heavier in the front will “push”. Major time gains in Autocross will come from good tires and seat time.

Side note. Make sure the alignment is done with the driver or driver weight in the car. If they don’t, find a new shop that does.

[bronxbomber252]

One issue is in most cases Bump Steer Kits are not allowed in ST classes such as the OP's class. But he is right that the car will be a little less stable. More stability = more understeer. I'n my experience a little toe out will not cause a dangerous situation nor any kind of instability that cannot be easily controlled. but you may find that the car gets blown around a little more easily by wind and that bumps/ruts have a greater effect on the direction of travel. But the car will rotate better on course.

You will get accelerated tire wear from this though, just an FYI but sometimes you make sacrifices for performance. (on my s2000 i run in front -2 deg of camber and .1 degrees toe out, and I run in the rear -3 deg of camber and .2 degrees toe in. but then again the s2000 is a tail happy car so that camber and toe is designed to keep the tail in line)