The video being 1 minute long and used as a counterpoint I thought it'd be a compilation video of 2 wheeling from all kinds of tracks and situations. Instead, it's just one freak thing on an off road track . Get back to me when you find videos showing cars 2 wheeling from the middle of smooth tracks.
When a car is turning, the tyres are causing a sideways force, limited by the grip of the tyres. Due to the change of direction, the mass of the body of the car will act with an equal force in the opposite direction. Because the force from the tyres act at ground level, while the force of the body mass acts at center of gravity, the difference in height will result in a rotating force. In a race car, the center of gravity is lower, so the opposing forces are acting at a much closer level, causing a smaller rotation force.
When the car hits a steep curb while cornering, a force is added to lift one side of the car upwards. Additionally, the tilt causes the center of gravity to rise, making the difference between the tyre force and the body mass force greater. This increases the rotating force. In the case of the road car it might be enough to make it flip (which happens when the center of gravity has passed over the vertical axis of the tyres). In case of the race car, it shouldn't be enough to make it flip, because the forces are still acting relatively close to each other, and the low center of gravity also means that it will have to tilt more than the road car before the center of gravity has passed over the vertical axis of the tyres.
To flip a race car, you need sideways forces much higher than the tyres can produce. Typically it only happens when the car goes sideways off the track and the side digs in to the ground, or when it hits a solid barrier.
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Bonus video:
Well I requested cars, not utility vehicles. All these have high centers of gravity and some with very narrow tracks and have been known to flip for decades. The strange thing is, I haven't seen these kinds of vehicles go on 2 wheels in GT6 nearly as often as NSX's, Lambos, Ferraris etc.Forgive the late-ish response, but I couldn't find this video till now (forgot that the name for these things is moose test..).
Pretty much exactly what you requested
Now keep in mind that the average sports car will show less extreme behaviour, but especially if you increase tire grip, it is still very similar.
Thanks for the detailed pictures and explaintions. The car I was using was the opera s2000 I think, which while not a race car, have a very low center of gravity and tuned and lowered suspension. But thanks again.
What I was simply saying, and using your diagrams for reference, is tires on the ground fighting the forces of physics being applied do not have the available grip to stop from slidding the the direction of the vehicle. Essentially this leads to a outward slide by the two wheels in contact with the ground where eventually all tires end up back on the ground. There are exceptions to this, its possible to get popped up past the point of no return or balance point like we called it on bikes and from there, its only quick steering or luck I guess that would save you. Looking at your diagram you see that the tires contact patch is slightly reduced, not as much as your pics show because the tires will compress and there is probaby some negative camber from the set up and suspension compression. Anyway, im just thinking out load now. Your physics are right and I understand the roll point of a vehicle and the center of gravity. Cheers. Ill stop rambling now.
All these cars are already known for bad behavior on "moose test" (and not only there.. )
But you don't expect this to happen to a GT-R R35 ..even with rs tires. Am not say it's impossible to happen.. I say ..every time i try to turn at Scwedenkreuz (ring) (and without hitting the kerb), the car tends to became a ....van ..
Try these settings.. ‘Ring / Gt r v spec ’09 / weight reduction(everything) only / rs tires / no aids / abs 1
You win. I didn't tried it with SL55 AMG but i tuned V12 Vantage instead, it behaves similar to SL 55 due to heavy weight. Stiffening front spring for about 10-20% harder than rear spring helped a lot! Now it understeers a little only in high speed turns. I'll try setting front RH a little higher than rear, front downforce and weight transfer from back of the car should push it to the ground when cornering. Is my thinking correct?Now I have not driven this car myself. But as far as I am aware, it is a fairly heavy car. The understeer in corner entry could very well be a result of weight transfer to the front end. If this is the case, you could try lowering the ride height and stiffening the springs, this should reduce it.
You win. I didn't tried it with SL55 AMG but i tuned V12 Vantage instead, it behaves similar to SL 55 due to heavy weight. Stiffening front spring for about 10-20% harder than rear spring helped a lot! Now it understeers a little only in high speed turns. I'll try setting front RH a little higher than rear, front downforce and weight transfer from back of the car should push it to the ground when cornering. Is my thinking correct?
As for the physics discussion, i would say that cars became more understeer, but maybe it's just coincidnece that this two cars i drive lately are behaving this way.
I haven't tried #2 but it wouldn't surprise me if true. GT5 had some of the worst low speed physics ever. I thought GT6 fixed some of it but it seems to have regressed recently.Rather than starting a new subject, I thought I would share it with you guys here in new physics thread a few things that bugs me.
I know there are bigger things to worry about like lack of uniform law of gravity, and it's just me being pedantic, but still...
1. Has anyone else noticed that when you spin and end up going backwards still being in high forward gear, trying to downshift in order to do reverse j turn kind of maneuver will end up on slowing down, as the gearbox allow you to go down to 1st gear only, while in the same speed range, pushing reverse button (by default triangle) will?
2. Thing that I've discovered just a couple minutes ago -On perfectly flat piece of tarmac, either using wheel or ds3, when you put in full steering lock, both ways, any car, any platform, in 1st gear, carefully hitting accelerator before you hit just shine below 3 km/h, the car will continue to accelerate up to12 km/h, while heading straight, up to 6km/h
I struugle to write correctly in english what i wanted to say, but i wanted to say same thing as you. Car would go on even without applying throttle by driver. Because of that static engine revs i was talking in previous post. To be honest, i never saw a car which would stall when on gear and off throttle when clutch gently raised.@andryush, sorry but you're "wrong", like I said earlier, on injection based engines it won't stall. Program inside ECU raise rev few along adding more throttle, not much, but some, depend code/car on each ECU.
So right and wrong, revs plays in certain area without user interrupt.
Try on real car: gently raise clutch pedal when 1st gear is on, if car isn't moving and gaining some speed you can contact to workshop and ask them to fix your car.
The grip is probably reduced when the tyres are at an angle, but the forces acting against them are also reduced, because when you're turning while the car is tilting, body mass isn't acting on the tyres to the same degree as they are when the car is flat on the ground...
The body mass (the winch) isn't going to try and move the wheels (the roots), it's going to attempt to rotate the entire car (tree).
What do you mean by power sliding?Fastest way to go is basically slow driving, no powersliding.
I imagine he means turning in early and 4 wheel drifting under throttle like rally drivers actually do to maintain the cars momentum and exit faster.What do you mean by power sliding?
Correct, but saying that "body mass isn't acting on the tyres to the same degree as they are when the car is flat on the ground" is incorrect.
We're actually applying the lateral force to all points of the tree (in the displayed plane) equally. We know that the top of the tree will bend before the roots give way but eventually the roots will move. This will be as a result of the momentum of the vehicle's mass exceeding the lateral grip of the tyres against the surface.
We can alter the proportions or severity of movement by suspending the wheels and absorbing as much of the sprung mass's movement as possible but ultimately all we're doing is affecting the way the body mass's inertia reacts against the direction of travel and against its own suspension.
Body mass never stops acting on the tyres unless you're airborne
In a lightweight car, the tyres might be able to accelerate the car up to 2G, while in a heavy car the same tyres might only be able to accelerate it up to 1G.
I'm sorry but that's utterly incorrect.
I think you might be talking about the resistance of the tyres in the lateral axis, but your terminology is mostly incorrect.
The lateral grip of a tyre (compromised in any instance by existing lontitudinal forces) is a function of the reaction between the surface of the tyre against the land's mu in any horizontal plane.
The grip is affected by how hard the tyre is being pushed away from the car's body towards the road, the mu of the surface, any existing forces acting on the tyre's surface, the pressure of the tyre, the heat of the tyre and so on.
The vehicle's accelerative forces are limited by this grip, they are not a function of it.