DSC OFF = what exactly?

[happy and angry]

I experienced the DSC in action the other day. I was on an unfamiliar road going faster than I should, when I went over a hill and the road dipped and went hard left, I was going too fast and the road was not banked, I hit the brakes and steered hard to stay on the road

Please don't "hit" the brakes and steer "hard" on an unweighted off-cambered corner, I can feel my heart in my throat from here.

 

[08cosmic3]

I had no chose. The road did not continue straight.

 

[johns]

i turn that s*** off so that i can spin the wheels going around a turn. that is fun

 

[TKMS3]

unweighted off-cambered corner

what (huh)

 

[08cosmic3]

Topping the hill with speed the car was not under full weight and the turn was not banked.

 

[happy and angry]

what (huh)

Cresting a hill will cause the momentum of a car to keep going up even as the road begins to move down. This causes there to be less effective weight on your tires, and a big portion of your grip is now created by the suspension pushing down on the road and not the weight of the vehicle. This means you have less grip. It is sometimes described as unweighting.

On a "flat" road, the road is generally designed to crown away from the center line of the road. Generally a corner will bank (is cambered) with the direction of the corner, making it easier to corner. In a cambered corner, weight transfer from cornering ends up pushing away from the center of rotation of your turn (as usual) but because of the slope of the road puts more effective weight on the outside tires responsible for turning. Sometimes a road settles or terrain doesn't allow it at you'll have a "flat" corner where the crowning of the road means the angle of the road is slight away from the corner (turn left, banked right). This is an off-camber corner, and it has the opposite effect on outside tire grip; you have less effective weight on the outside tires and they thus have less grip.

This is a particularly dangerous situation in a corner. Two very famous corners on motorsports are designed like this: the Eau Rouge/Raidillon complex at Circuit de Spa-Francorchamps in the F1 Belgian Grand Prix, and the Corkscrew at Laguna Seca. Eau Rouge is at the bottom of a hill, and leads up to a long sweeping right that crests to an off-cambered left called Raidillon, and the Corkscrew is an uphill off-cambered cresting left leading to a downhill-offcambered right. Scary s***, go check out some videos.

Sharp inputs to your car of any sort can be very bad in these situations. You have limited grip on all four tires, and things like hard braking can overload the front outside tire mid-corner while unweighting even further (by braking) all three others, putting you in a most ideal situation for a spin. Momentum wants to push the rear out, the rear is unweighted, the front outside tire is the most "grippy" and will easily act as a pivot.

08cosmic3 sounds like he knows this, I'm just glad he was able to pull out of it. Of course, I don't know how bad the unweighting/cambering was, how fast he was going, how sharp the corner, etc, but it sounds like it was a close thing. Plus he has the fastest colour, and that never hurts.

 

[J-Villa]

Cresting a hill will cause the momentum of a car to keep going up even as the road begins to move down. This causes there to be less effective weight on your tires, and a big portion of your grip is now created by the suspension pushing down on the road and not the weight of the vehicle. This means you have less grip. It is sometimes described as unweighting.

On a "flat" road, the road is generally designed to crown away from the center line of the road. Generally a corner will bank (is cambered) with the direction of the corner, making it easier to corner. In a cambered corner, weight transfer from cornering ends up pushing away from the center of rotation of your turn (as usual) but because of the slope of the road puts more effective weight on the outside tires responsible for turning. Sometimes a road settles or terrain doesn't allow it at you'll have a "flat" corner where the crowning of the road means the angle of the road is slight away from the corner (turn left, banked right). This is an off-camber corner, and it has the opposite effect on outside tire grip; you have less effective weight on the outside tires and they thus have less grip.

This is a particularly dangerous situation in a corner. Two very famous corners on motorsports are designed like this: the Eau Rouge/Raidillon complex at Circuit de Spa-Francorchamps in the F1 Belgian Grand Prix, and the Corkscrew at Laguna Seca. Eau Rouge is at the bottom of a hill, and leads up to a long sweeping right that crests to an off-cambered left called Raidillon, and the Corkscrew is an uphill off-cambered cresting left leading to a downhill-offcambered right. Scary s***, go check out some videos.

Sharp inputs to your car of any sort can be very bad in these situations. You have limited grip on all four tires, and things like hard braking can overload the front outside tire mid-corner while unweighting even further (by braking) all three others, putting you in a most ideal situation for a spin. Momentum wants to push the rear out, the rear is unweighted, the front outside tire is the most "grippy" and will easily act as a pivot.

08cosmic3 sounds like he knows this, I'm just glad he was able to pull out of it. Of course, I don't know how bad the unweighting/cambering was, how fast he was going, how sharp the corner, etc, but it sounds like it was a close thing. Plus he has the fastest colour, and that never hurts.

qft.

I was taught that you take 100% of the grip avalible to you and subtract the percentage of throttle and braking you are applying, and that leaves you with the % of possible grip left for your tires to grab. Of course it's not a true mathematical formula, but gives you the general idea that when grip is not aplenty, you need to be gentle on the pedals.