Rear Suspension Geometry

[jas1159]

Hi Guys,

Just wondering if anybody can shed some light on how the rear suspension geometry on a custom build should be setup in terms of camber change, I know this is different for every vehicle but also know there are some commonality.

My main question is should i make the rear end of a mid engined RWD vehicle better in roll or better in bump/droop than the front?! now i cant make it the same as my track width is different.

so its either better in the corners or better in bump / droop and maintaining stability in a straight line... now the obvious approach is to say maintain greater contact patch in the straights as its the drive axel and this is when it needs grip however with the power it may need added grip in the corners where it counts... to stop it from spinning... so to sacrifice the straight line grip for cornering ability?!

I was advised to raise my rear Roll Centre in relation to the front as i see many other cars have a similar setup, by doing this i automatically make the rear end better in the corners than the front.

Raising the RC to say 70-80mm gives a smaller swing axle and results in major camber change with bump/droop but minimal in roll.

All comments will eb greatfully recieved.

Thanks
Jason

[chrislandy]

I think it is general accepted that the rear roll centre should be higher than the front and to try and keep the angle between them the same throughout the axle movement. If you are using independant rear suspension with unequal wishbones then my understanding is that you should use the bottom wishbone to set the roll centre movement and the top wishbone should be adjusted/played with to try and control the camber change.