guys aquainted with physics....

[The Mic]

ok so I am having a little spat with my friend. ff, frontship; front wheel drive and you know fr.....

anyways... (assuming vehicles have equivalent power)She says car X (FF) would have better traction than car Y. Now, I say that car Y (FR) would have better traction than X because of the drive train. Its fundemental. As far as acceleration goes, something that is pushed is going to be faster than something that is pulled from the start.

I want to hear opinions. Am i right?.

.

.p.s. if you disagree with me your opinion isnt welcomed.......

*edited, got pulled & pushed backwarkds
Modified by S13GUY at 11:15 PM 12/10/2004

[base9se]

too many varying variables floating up inthe air...example tire size, curb weight, tire traction, ahhh too many.

And something being pushed is going to be faster than being pulled, especially at the start.

[The Mic]

ok.. Everything is identical except for the fundemental features. clearer now?

[Nismo_Freak]

It's not a matter of pushing or pulling cause it's a wheeled object and the force (torque) is rotational not linear. That theory is a result of physical constraints within our bipod stance. Force requires triangulation within the body... pushing something offers a superior angle.

In terms of traction the FR has better traction as a result of the weight transfer (10% +/- 1% or so per wheelbase, CoG, etc.) giving the tire more load which then translates to more friction at the contact patch. There are limiting possibilities but the greatest amount of traction is found in a FR setup (AWD not considered).

[The Mic]

As far as acceleration goes, something that is pushed is going to be faster than something that is pulled from the start.

so Alan, would this statement hold true?

[Nismo_Freak]

so Alan, would this statement hold true?

Assuming you have a person pushing an object yes. The angle of force can be lower because the hypotenuse (length of body) is not limited by the rope or some other device. This prevents effort from exerting a lifting force which is wasted work. Granted there are factors like friction coefficient of the object, surface area applied to the ground, and the weight of the object. Sometimes pulling is a superior method.

In the case of a car though, you simply have a rotational force being applied through a frictionable surface (tire ---> pavement). It doesn't matter if it's FF or FR in the regards of X amt of torque + infinite traction = work. It's when you take a limiting factor like traction into account.

[EZcheese15]

If all things are equal, pushing nor pulling makes a difference. If a car is being pushed by say 100 lbs of force at a 0 degree vector, then that is equal to being pulled with a -100 lb force at a 180 degree vector.

What Alan is talking about is throwing in the concept of angled vectors, such as the suspension dynamics changing when force is applied.

On a FR car, the suspension is usually set up so that the force vector is not at a 0 degree angle, but at say an 10 degree angle. This causes the opposing force vector (for every action there is an opposite and equal reaction) to apply a downward force vector (-90) and a forward force vector (0). Which in turn sacrafices a forward force of 100 lbs for a smaller force, but also has a downward force for more traction (a forward force of 100 lbs is useless if the tires are spinning due to lack of traction). A FF car reacts the same way but instead has the forces working against it.

Basically, if neither suspensions allowed movement, they would be equally as fast. But since the suspension does move, a FR will launch faster with all other factors equal.

This is why a FR drag car usually has a high mounted engine (to increase the downward force vector on the rear wheels as the torque attempts to spin the car around the rear axle). And also why a FF drag car uses a roll bar in the back (to minimize rotation around the front axle).