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Drift physics.......?

hayai32

By hayai32,
in General Automotive Discussion

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hayai32 Collaborator

hayai32

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Ok, so ur in a drift..... Why is it that when your rear wheels are spinning faster they have less traction (ie; increase throttle = decrease traction)? What is the scientific explanation?

I guess that having ur wheels spinning faster decreases a quantity of the co-efficient of friction and hence reduces traction but what quantity? Maybe contact area of tyre decreases...

This is for a physics assignment by the way.

Thanks in advance for any help.

Col

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Laurence Mentor

Laurence

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Unless you are in a car with aerodynamic downforce the tyres are pressed to the ground by the force of gravity. This is where you get your grip from. By pressing the accelerator you apply a force Fapp and as long as that force does not exceed your force of friction f you are in a grip driving situation. Once Fapp > f you are in a drift scenario... The coeff of kinetic friction is lower than the coeff of static friction so yes once the wheels are spinning they will stay spinning until Fapp is less than...

I have to go and see a movie. Just look at this site...

Forces12.gif

http://www.ac.wwu.edu/~vawter/PhysicsNet/T...ces/Normal.html

http://www.ac.wwu.edu/~vawter/PhysicsNet/T...ionalForce.html

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hayai32 Collaborator

hayai32

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deano_82 If there was an award for tuff avatars, yours would win it.

Gojira Those links are pretty good but... I need to know why a wheel spinning at 120kph(wheel rotation speed, not car speed) has less lateral traction than a wheel spinning at 90kph. eg; When you initiate a drift... if you apply 100% throttle the tail will hang more than if you apply 75% throttle. Why is lateral friction reduced with an increase in wheel rotation speed?

I cant get away with saying "The faster it spins the less traction" (this is what i have already). I need to know why a faster spinning wheel has less lateral traction.... I have a stong hunch it has something to do with reduced contact surface of tyre or similar...

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