TOE: Can such a small change, cause all to break loose?

[Lambob]

Hey fellas,

I took out the long neglected BMW GTR for a spin on real practice Nordschleife, tuned to 505pp with only Sport exhaust, and RS tires, and suspension mod.

I used default supension and set all cambers and Toes to 0 / 0 , and really like the way it handled around the ring, pulling off a 7:00 laptime first time around, thinking it has potential ;p for online matchups.

I started with .01+ front, and.01- rear, and immediately sensed improvement in turning everywhere, where throttle release, and mild application rewarded me.

Then I dared to try .02+ front to see if it would improve anything, and lo and behold, the car oversteered on every throttle release application, as if a crazy hamster was at the wheel.

.02 toe, that was it, there are 98 more adjustments higher up.

is it supposed to have such a radical change?

reverted back to +.01 / -.01 , custom tranny FD to 294 km/hr, and am pleased with 6:52s, Brake 4/5, LSD 8/16/10, springs and dampers as default. ARB 4/4. This car doesn't go fast on straights, but it holds the corners with confidence, and with minimal slide, as to reason it rewards the lap time.

I am beginning to wonder if camber and toes have negative impact on RS tires on the Nur, same with the Evora. There is much stability setting them all to 0, perhaps the roughness of this track (programming) needs all the tire contact it can get.

p.s my offline tunes work just as well online.

 

[dr_slump]

I am beginning to wonder if camber and toes have negative impact on RS tires on the Nur, same with the Evora. There is much stability setting them all to 0, perhaps the roughness of this track (programming) needs all the tire contact it can get.

Toe doesn't increase nor decrease the size of the contact patch.

 

[SolidSnake7735]

Toe settings are classified as "Wheel Alignment" just as Camber. It may not increase/decrease the contact patch but it does make a difference in handling. I usually run negative toe in the front tires and positive toe in the rear tires on most of my setups. Such settings might result in quicker turn-in and higher stability through the corners and on corner exit.

 

[Lambob]

when tuning, can such a small micro change whereas all else remains constant, cause such handling differences? perhaps the car was already at it's breaking point..

 

[SolidSnake7735]

when tuning, can such a small micro change whereas all else remains constant, cause such handling differences? perhaps the car was already at it's breaking point..

Probably.. BMW's are cars which when i tune, i tend to veer too far from the factory settings for LSD and Spring rates. But with wheel alignment even though the stock setting for the FC Suspension is all zeros with 0.20 toe in the rear, the real-life settings for most is above that. They really vary from car to car. There was a thread in a different sub-forum (or probably this one, long ago) about wheel alignment settings. There was speak of how in most real life sports cars they have high rear toe settings for stability. Angles in excess of 0.50 degrees.

So in GT5 some cars would benefit from higher (or just different) toe settings while others may not benefit much or at all.

And yes... increments of 0.01 degrees can make a significant change in handling

 

[Poontanir]

Another thing is front and rear toe work together. Most road cars run even toe in front and rear. If you wonder from this the affects can be severe. when you set the front with .01 toe in and the rear with .01 toe out this provides .02 degrees of extra turn as weight transfers to the outside wheels. If you do the opposite you would have .02 degrees of reduced turn as weight transfers. With .01 toe in front and rear the car won't turn but crab-walk at .01 degrees as weight transfers. The trade off for all this is tire wear, by having tires pointed in different directions. Tire wear may be well or poorly modeled in GT but it is modeled, and camber and toe have the biggest affect.