SpeedRacer629

Before you ask, yes, I did search, but I couldn't find anything other than how to recover from it, how to repair it, and/or what causes it.

I have a background in open-wheel racing. I know that the most effective braking is when the brakes are at the point just before lock-up. When I first started out, my driving instructors tried to explain wheel lock-up. It was something along the lines of:

"Imagine a chart between 0 and 10, 0 being no traction, and 10 being full traction. When your wheels lock up, you essentially drop from 10 to about a 3."

Does anyone know WHY this is? I want to say it has to deal with the static vs kinetic friction of the tires, but I'm not entirely certain as to what the relation is.

EricB

iTrader: (7)

the tires stop rolling?

SayNoToPistons

iTrader: (8)

Yes, you are correct. It is essentially the difference of static and kinetic energy (kinematics/friction). Basic physics applying the coefficient of friction. mu times N.

When a wheel locks, which obviously includes the pause of rolling movement of the tire on the pavement, that is no longer a static friction as the tire is now SLIDING ON THE PAVEMENT. That is what is considered KINETIC FRICTION. We want to maintain the maximum static friction not only in braking, but in corner also. Tire control in other words. Static friction = grip, kinetic friction = no grip.

That is just the gyst of it. Of course we can stab in equations of both static and kinetic friction, but that is irrelevant for 99.999% of drivers. . Like you said, we want to maintain the "10" for any competitive performance driving.

dannobre

iTrader: (3)

Basically the tire is sliding...and overheats the local contact patch it is sitting on...it melts and get really greasy...no grip.....

The car has ABS...it isn't going to let you lock up the wheels anyway

SayNoToPistons

iTrader: (8)

Coefficient of fiction is the main factor of the original post, not thermodynamics...

boggle

i have had the rear lock up braking hard into a tight chicane. i can only assume its because the car became un ballanced? the antilock brakes did not come on either.