Anti-sqaut/dive FBD

[erandolp]

For a some time I thought I really understood anti-sqaut/dive theory, until I tried to illustrate it in a free body diagram. I am having a tough time understanding how the IC applies moment to the center of gravity of the car and how it is related to the rear tire contact patch. Any help would be appreciated.

Regards,
Eric Randolph

 

[erandolp]

I may have had a eureka moment; is the moment created because the tire and the suspension are not vectoring through the same points? If this is the case I still don't follow where the tires force vector is derived from.

 

[GregLocock]

The tire force vector for braking is reacted at the contact patch. For tractive forces it is applied at the wheel centre.

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Bribyk]

Your suspension can be reduced to a single vector from the contact patch to the vehicles CG, in both side and front/rear views, via the geometry/kinetics. All of your tire forces (cornering, braking, accel) are applied to the vehicles CG along that single vector. When this vector isn't horizontal (parallel to road) you get dive/squat in braking/accel and jacking forces in cornering.