XRAY - Model racing cars

When determining roll centers it does not matter if the suspension links point “>” or “<” you still draw the imaginary lines from the links to there intersection points and then draw a line from that point through the center of the tire and through center line of the chassis. With the arms are set so that they form a “<” you get a very low roll center which will be below the tire. Probably not something you want in all practicality. Now if the arms are set parallel “=”the roll center is located on the ground.



Hope this helps with your question.

Eric

Thanks Eric, didn´t know that.

And with the arms like < the camber change would work the other way, ie you would gain positive camber (the top of the wheel would lean out more).

Excellent point SmartArse88. To further explain so others understand, if you draw an arc with the center at the intersection of the suspension linkages and goes through the center of the tire or hub it will show how the camber will change as the suspension is compressed. The further the intersection is from the hub the less camber change will occur. In the “<” case the intersection is outside of the tire so the arc swings away from the chassis causing positive camber gain. Once again most likely an undesirable situation.

Thanks Eric,

I realised afterwards that I maybe shouldn't have been so cryptic!

Thank you very much Eric and SA88!

Excellent explanations that answer my question to the fullest!

Col is correct. With parallel arms the intersection of the two arms is some were out in infinity therefore if you draw an arc from there intersection you would get an arc with a infinite radius, in other words a straight line. Now if the arm are parallel and of unequal length you will get camber change when the suspension is moved. If the top link is shorter than the bottom you will get negative change. If the top is longer you will get positive camber change. As far as the arc through the hub you have to keep in mind that the roll centers changes anytime the suspension is moved. Hopefully the picture below will make it more clearer.


Eric