0.7 Toe out for autox?

[joe86]

I had a shop which has experience with performance bmw stuff and themselves have a bmw e36 auto x car align my car for auto-x and mark the plates for street use. They gave me -.7 degrees total total toe out at max camber which came to 3.3 and 3.5. I asked them about the toe and they said their auto-x car has very close to .7. Doesn't that seem like to much toe out even for autocross? Also is it important to bring the camber in so both sides are 3.3?

[RyanDavies]

I would highly advise against toe out on either end of the car. I'm assuming this is front, but, uh, that's very silly. Car will turn in very well then go to instant push, in my experience.

[joe86]

Originally Posted by RyanDavies

I would highly advise against toe out on either end of the car. I'm assuming this is front, but, uh, that's very silly. Car will turn in very well then go to instant push, in my experience.

Yes. I am talking about the front

[Bimmer-Bob]

Toe-out? You shouldn't have any toe-out.

Last time I had my alignment done, I went to a very well-respected guy who does it the old school way (Chassis Masters in San Diego) and I requested zero toe. He actually recommended slight toe-in (my notes say 3/16") due to the fact that he said the Mac strut set-up would tend towards toe-out under hard braking (i.e., as for corner entry) and so mild toe-in "at rest" would effectively be zero toe when it mattered.

Weather you buy that or not, I would think that toe-out at baseline would be no good.

[tuj]

I prefer zero toe front and rear on a FR format car. On a FF, rear toe out (if the suspension is independent) can help the car rotate under trail-braking.

Front toe out is usually used to intentionally decrease stability and get the car to turn in faster. It also puts the tires under *constant* slip angle, lots of autocross-er's use toe-out in front.

http://farnorthracing.com/autocross_secrets22.html

Camber might be ok, if they ballasted the car on the driver's side when they had it on the alignment rack. But yes, generally it should be within 0.1 of the other side.

[jafo1701]

I toe out just a tad, .05 in front with .10 toe in on each side in the rear. It helps with turn in and the car tracks perfectly. The car has been tracked and autocrossed. I think .7 Toe would be excessive though.

[Ginger_Extract]

I have about 1/8" total toe out up front, unsure what that translates into for minutes or degrees. The car is autocrossed/tracked enough to offset inner tire wear.

[lowside67]

My target alignment is .10 total toe out in front and same toe in rear.

Mark

[joe86]

Thanks for the responses. The car definitely starts to push more than it should after turn in and I am finding that I need to be more aggressive with the steering wheel input. Seems like .1 out would be a good starting point I think I will get a longacre toe bar so I can mess around with the toe myself and find the sweet spot.

[dbronnik]

Originally Posted by lowside67

My target alignment is .10 total toe out in front and same toe in rear.

Mark

Are you saying .10 total toe OUT or .10 total toe IN for the rear?

I target the same in the front as you, but I use .10 total toe IN for the rear..

[lowside67]

Sloppy wording on my part. .10 total toe out for the front front, .10 total toe in for the rear.

[joe86]

I bought a longacre toe gauge (didn't buy the tire scribe, used a block of wood with a screw in it) and changed my front total toe to -1/8"/-0.28 deg. out (was at a little more than 1/4") car feels much better and easier to drive at autocross. The toe gauge is accurate and easy to use so I will continue to experiment with toe settings.

[RyanDavies]

A rhetorical question to some degree: Why would you want toe out up front?

Imagine the loaded wheel in a turn, and you'll understand why I'd hesitate to do so (in addition to the impact toe out has on braking stability, and the rolling resistance impact).

[joe86]

Originally Posted by RyanDavies

A rhetorical question to some degree: Why would you want toe out up front?

Imagine the loaded wheel in a turn, and you'll understand why I'd hesitate to do so (in addition to the impact toe out has on braking stability, and the rolling resistance impact).

Well I have been doing a lot of reading on this lately and this is my understanding: It makes for quicker initial turn in to a corner/slalom. This seems to be more important for slower/tighter corners like the ones seen in autocross then the higher speeds seen at the track. In the moment between when you turn the steering wheel and when the weight transfers to the outside tire its better to have the inner tire (which, while cornering, will be traveling around a smaller circle than the outside tire) pointing towards the corner ready to grab/grip the pavement. This actually transfers the weight to the outside tire quicker. You don't want too much because then you have to turn the steering wheel more to get the outside tire pointed in the correct direction when the weight transfers. Also too much can cause a lot of instability. How much is good depends on tire stiffness/sidewall height you may want more toe out if going with a taller tire as it can twist/deflect more (can have a higher slip angle). It also depends on your car setup if you install a stiffer suspension the weight will transfer faster which means you will want less toe out. The link that someone posted earlier is a good read.