kingpin inclination and camber change

[NSXR]

hi,

i am currently learning suspension geometry and i am really having a hard time understanding the relationship between kinpin inclination and camber change. from what i read, a positive kingpin inclination (upper balljoint closer to the center line of the car) will cause a positive camber change upon steering of the wheels and vice versa.

i am really having a hard time visualizing this because if the kingpin axis is positive wouldnt that increase negative camber upon steering of the wheels?. i have tried modeling an SLA suspension with wooden sticks but with no luck because i cant get an accurate measurement. is there a simple program i can use to simulate this? or am i completely misunderstanding this relationship?

thanks in advance

 

[GregLocock]

I think you are wrong. For simplicities sake set the camber equal to -kpi, it the wheel face is parallel to the kp. Now steer the wheel by 90 degrees. It is now vertical, ie zero camber.

Cheers

Greg Locock

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

 

[Fabrico]

As far as your question is concerned, the suspension should be left out of the picture. The ball joints are simply two points representing a single line, just like a king pin. This should be very easy to model.

Once you get that visualized, you can move one point back or forward and see the effects of castor.

 

[FoMoCoMoFo]

yes, sounds like you've got your kingpin angles and effects mixed up. axis inclination & caster

 

[GregLocock]

The craziness is that kpi is positive in at the top, camber is positive out at the top.

Blame the SAE!

Cheers

Greg Locock

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

 

[NSXR]

"... For simplicities sake set the camber equal to -kpi, it the wheel face is parallel to the kp. Now steer the wheel by 90 degrees. It is now vertical, ie zero camber. "

that visualization helped alot and yes blame SAE for the confusion lol.

thanks again