new astra rear suspension...

[Asa-James]

apparently its a completely fresh and brilliant design, but i cant get my head round it. Evo magazine describes as...


The new Astra still has a torsion beam [H-frame like a nova i assume]but now the trailing arms rear ends are linked by a Watt's linkage anchored to the floor in the centre, so the arms can no longer defelct laterally under cornering forces.

i've just done a couple of minutes research on the net and all i can find it fitted to is tuned new generation mustangs (saleen versions etc)

would i be right in thinking it just ties the rearmost part of the beam to the centre of the car? and could this be made to fit a nova? if so, what benefits would it give?

and a quick couple of pics...
http://www.racetorations.co.uk/Parts/AXL407instA.jpg
http://www.totalcontrolproducts.com/vehicles/tcpracecar/support/tcp93.jpg

[Asa-James]

just found this on Wiki


Watt's linkage is used in the rear axle (http://en.wikipedia.org/wiki/Beam_axle) of some car suspensions (http://en.wikipedia.org/wiki/Suspension_%28vehicle%29) as an improvement over the Panhard rod (http://en.wikipedia.org/wiki/Panhard_rod), which was designed in the early twentieth century. Both methods intend to prevent relative sideways motion between the axle and body of the car. Watt’s linkage however approximates a vertical straight line motion more closely, and does so while locating the centre of the axle rather than toward one side of the vehicle, as more commonly used when fitting a long Panhard rod.
It consists of two horizontal rods of equal length mounted at each side of the chassis. In between these two rods, a short vertical bar is connected. The center of this short vertical rod – the point which is constrained in a straight line motion - is mounted to the center of the axle. All pivoting points are free to rotate in a vertical plane.
In a way, Watt’s linkage can be seen as two Panhard rods mounted opposite of each other. In Watt’s arrangement however, the opposing curved movements introduced by the pivoting Panhard rods are compensated by the short vertical rotating bar.
Watt's linkage can also be used to prevent axle movement in the longitudinal direction of the car, this is however more common in racing suspension systems. This application usually involves two Watt's linkages on each side of the axle, mounted parallel to the driving direction.


http://upload.wikimedia.org/wikipedia/commons/5/51/GSFRRearViewUnderCropped.jpg

[mowgli]

surely a panhard rod would be easier to fit. as its just one long rod as opposed to 2 shorter ones.
the main problem to fit any of them is the fact that there are the exhaust & the tyre well in the way
you can stop sideways flexing of a nova rear beam by putting decent mounting bushes in it.....

[Asa-James]

that was mentioned, but this new fangled design(which appears to have been around since steam trains!) keeps comfort up and noise levels down.

[mowgli]

tbh, everybody else was fitting multilink rear beams back in the eighties, and gm are playing a bit of catchup here.... but I don't think retro fitting an extra sideways link will help much with ride. it was used on mk2 escorts to keep the driven wheels on the ground.