Mods: If this is in the wrong section, please feel free to move it. I thought this section of the forum would be the best location for it. I could be wrong though.

Coefficient of Traction Defined: The degree of traction between the tire and the ground is called the Coefficient of Traction.
A spinning wheel does not deliver useful power to the ground. The two factors which keep a wheel from spinning are the mass it carries and the traction available from the ground conditions.

Since there is never 100 percent adhesion, the coefficient is always less than 1.0. The result of multiplying the weight on the drive axle times the coefficient of traction represents the maximum force which can be transmitted before the tire spins. It is worth noting that in the all sources of information I found while researching this subject, the only variable considered was the ground surface. Tire type, construction, tread style, or rubber compound were not given any consideration. Probably the reason for this is that the variations in the ground surface overwhelm any variation of tires in this matter.

Coefficient of Traction for Rubber Tires on Various Surfaces
Source: Forestry Handbook by Karl F. Wenger (1984)

Concrete (dry) .70
Asphalt (dry) .50
Asphalt (wet) .45
Gravel (packed, oiled, dry) .50
Gravel (packed, oiled, wet) .40
Dirt (packed, dry) .50
Mud .15-.40
Snow (dry, on loose gravel) .25
Ice (free of snow) .07

Btw, I did not write this. It is a direct copy and paste from http://www.saltflats.com/traction.html, and the author Dan Wright deserves all the credit for the work he did in the article "Bonneville Traction."

 

Cool info. Thanks!

 

Interesting....

 

trust me there's a difference between dry and wet snow!

 

I'm from Utah. I can tell you all about it.

The only number I didn't list on there was salt. The big reason is because most people on this forum won't take there cars to the salt flats, yet alone ever see them in person.

 

good find, i remember going over some of this in physics a while back, i thought it was pretty interesting stuff

 

Thanks. I was hoping this would get stickied because it is useful information.

 

What that fails to take into account is the differances in tire compounds which can greatly affect traction. No one ever tries to cover all aspects when they study something like this, they just get a small snap shot that is very useful in the world of "theory" but can never be aceratly applied in reality.

 

Yeah, that was covered in the OP. Thanks for reading though.

 

well this is good to know...but not what i was looking for...im trying to figuere out what the Drag Coefficient and Frontal area of our cars is?

 

I would like to know of Coefficient of drag myself. I know the toyota prius has probably the best aerodynamics around, lol.

coefficient of drag = resistence to air.

nm, found my answer

http://en.wikipedia.org/wiki/Automob...ag_coefficient

 

Drag Coefficient 0.324 Cobalt

thanks...now i need to find the frontal area

or the complete CDA of this car