What do you understand by the limit of grip...

[Martin A]

and how can you possibly control the car beyond it?

Just curious to find out people's views.

Regards

Martin A

[vonhosen]

Martin A said:

and how can you possibly control the car beyond it?

Just curious to find out people's views.

Regards

Martin A

I'd personally say it's defined by the friction circle & you can control the car beyond it because you have control of the factors that can bring you back within that circle.

[7db]

But grip isn't binary. It falls off.

[GreenV8S]

I'd say it's the point where the tyre has exerted the maximum force it is capable of. Even if you're past the peak, you can still have some control over the magnitude and direction of the force so you can still have control over the vehicle - it's just a lot less positive than if all four wheels have grip to spare.

[7db]

I'd think of it as the limit of linear behaviour (force response to slip angle)

[smart51]

The limit of grip is not a sharp point but happens gradually over a range of speed.

At low speeds, turning the steering wheel makes the car turn in positively. Pressing the accelerator makes the car speed up but not change its line. Try this at progressively higher speeds and you come to a point where the steering feels light and turning the wheel in has less affect on direction. Putting on the power makes alters the attitude of the car, inducing a little more understeer or oversteer. Ultimately you will find a speed where the car will corner at a steady speed but adding more steering will have no effect on direction and adding more power will affect the course of the car. You are now on the edge of grip where tyre slip angle becomes a skid. More speed through the corner will mean you can't turn as tight as you want without understeer or you are power sliding with oversteer through the corner. "Control" at this point is merely influence on the direction of the car. With practice, drivers like Tiff Needell can balance the car's skid with rapid steering inputs and small changes in throttle. Racing drivers need to master these techniques, not to use them in driving but to control any situation that may develop unexpectedly.

On the road, if you start to sense that your grip is starting to run out, you are driving too fast for the road, the conditions or the car.

[vonhosen]

7db said:

But grip isn't binary. It falls off.

But the circle doesn't have a thin sharp line, it has a graduated shading to represent the transitional period between the linear elastic behaviour & slide.

[BOF]

Martin,

"What do you understand by the limit of grip"

In theory...nothing.

In practise...cutting the grass with the nearside tyres at Millbrook on the handling track on a right hander...expensive with Pirellis.

Lesson?

Limits? 'That's what I paid £560 for today...don't do it again'...but now I know...roughly...

BOF

[coxyboy83]

It is there to be exceeded

Edited by coxyboy83 on Tuesday 21st October 13:23

[Pugsey]

coxyboy83 said:

It is there to be exceeded

Edited by coxyboy83 on Tuesday 21st October 13:23

+1

My understanding is that life only begins beyond the limit.

[Vladimir]

vonhosen said:

7db said:

But grip isn't binary. It falls off.

But the circle doesn't have a thin sharp line, it has a graduated shading to represent the transitional period between the linear elastic behaviour & slide.

WTF? The limit of shouldn't be explained in such a formulaic way, too many variables. Just enjoy the slide.

[7db]

Pugsey said:

coxyboy83 said:

It is there to be exceeded

Edited by coxyboy83 on Tuesday 21st October 13:23

+1

My understanding is that life only begins beyond the limit.

For some people, they find that's where life ends too.

[vonhosen]

Vladimir said:

vonhosen said:

7db said:

But grip isn't binary. It falls off.

But the circle doesn't have a thin sharp line, it has a graduated shading to represent the transitional period between the linear elastic behaviour & slide.

WTF? The limit of shouldn't be explained in such a formulaic way, too many variables. Just enjoy the slide.

The circle accounts for variables because it's radius is also variable.
Where you slide is a variable that can result in a smile or a cost for you.

[p1esk]

vonhosen said:

Vladimir said:

vonhosen said:

7db said:

But grip isn't binary. It falls off.

But the circle doesn't have a thin sharp line, it has a graduated shading to represent the transitional period between the linear elastic behaviour & slide.

WTF? The limit of shouldn't be explained in such a formulaic way, too many variables. Just enjoy the slide.

The circle accounts for variables because it's radius is also variable.
Where you slide is a variable that can result in a smile or a cost for you.

It'll be the latter if Von catches you at it, er, sliding, that is!

Best wishes all,
Dave.

[norasport]

Do you mean the limit of "maximum" grip?

If we are performance driving on the track or in competition then to get round the corner at the highest speed we want to find and maintain the maximum grip available for cornering.

The type of skid control tuiton I, any many others offer, provides the chance, in a safe environment, to search for the holy grail of maximum gip but to avoid the difficulties of what happens when we ask too much and enter the interesting world of nibbling the edges of maximum grip and exceeding it and entering a skid, where grip very quickly falls away, but whilst trying not to compromise the ability to control the car and aiming to quickly come back to the point of maximum grip; this is what any limit handling course is all about.

Try it, it's fun and a real test of skill, but we have moved some way from safe road driving or from advanced driving as described in this forum.

But now consider how many single vehicle loss of control accidents there are on the public road, and how many of those lead to fatalities, then argue that this (limit handling)is not a skill (even in basic form) that if more widely shared would not save lives.

[GreenV8S]

norasport said:

But now consider how many single vehicle loss of control accidents there are on the public road, and how many of those lead to fatalities, then argue that this (limit handling)is not a skill (even in basic form) that if more widely shared would not save lives.

I seem to remember reading (most likely here on PH) that the safety benefits from improved car control were on average more than outweighed by the false confidence that lead to increased risk taking in adverse conditions.

[Mr_annie_vxr]

GreenV8S said:

norasport said:

But now consider how many single vehicle loss of control accidents there are on the public road, and how many of those lead to fatalities, then argue that this (limit handling)is not a skill (even in basic form) that if more widely shared would not save lives.

I seem to remember reading (most likely here on PH) that the safety benefits from improved car control were on average more than outweighed by the false confidence that lead to increased risk taking in adverse conditions.

Trick would be to avoid getting into a situation where you exceed maximum grip in the first place.

[35secToNuvolari]

The limit is usually right when you think, "I can push a little bit harder."

[Pugsey]

7db said:

Pugsey said:

coxyboy83 said:

It is there to be exceeded

Edited by coxyboy83 on Tuesday 21st October 13:23

+1

My understanding is that life only begins beyond the limit.

For some people, they find that's where life ends too.

True. The talentless ones I guess.

[GreenV8S]

Mr_annie_vxr said:

Trick would be to avoid getting into a situation where you exceed maximum grip in the first place.

Yes sure, but no way I'm walking home in this freezing weather. I can handle it - I've had skid pan training, doncha know?