Toe in - toe out?

[Peter Mallett]

Yeah my point was more that once into the corner the outside wheel will be loaded and thus will "straighten" therefore if you set to toe-out you effectively induce understeer. But that was my experience and ultimately as Gordon suggests it really depends very much on the car.

[ian_w]

Dallara F3 cars are set-up with toe-out on the front and toe-in on the rear, this is a pretty standard setting for a single seater machine.

[itdontgo]

The fronts are not parallel once you turn the wheel as presumably every car has ackerman steering. Also once you're asking the tyre to produce a decent bit of force you'll find the direction the tyre is point and the upright and wheel are pointing are two different things. So even at the rear you won't have a nice parallel contact patch. So I wouldn't worry about a bit of toe out.

It can be to your advantage. On the limit most dry tyres will have a slip angle of about 7-10degs. At the rear your inside tyre will have a higher coefficient of friction because it is lightly loaded. Depending on yours tyres the inside might be able to run a higher slip angle due to the lighter vertical load. It will certainly drag more with increasing slip which will pivot the car. So if you have 0.5deg toe out on each rear wheel your inside tyre will run at 1deg more slip than the outside which may give it more grip during steady state cornering

Forgetting the toe setting for now assume you have rear wheel steering. If your tyres are both pointing outwards (as in toe out) the car chassis will run at this angle in a straight line meaning the front wheels will have to be turned by the driver a similar angle to compensate.
With toe out you'll get to your steady state cornering condition quicker because the heavily loaded tyre runs at an angle which requires less steering input for a given corner radius. Additionally the tyre which was pulling the car straight in a straight line (the inside tyre) will disappear upwards and off the road during the turn in phase as the car rolls and the damper rebound valving reduces the vertical load during turn in. Eventually it will return the the steady state vertical load where the extra slip angle might give it extra grip!

Running toe out will certainly amplify the affect of your rebound settings

[MGDavid]

Good thread revival (only 6 years!)

[itdontgo]

Originally Posted by MGDavid

Good thread revival (only 6 years!)

Yes... anyway who would like to buy my patented toe out ideal setting kit only £1999.99.