Super high tech beam axle?

While I never thought I would say this... there is part of the Chevrolet Cruze that I find simply amazing:

At first glance, the torsion beam rear suspension looks pretty unimpressive, but chassis engineers have incorporated some interesting features. Because the Delta II platform is designed to be sold in markets around the world with various bodystyles, flexibility was needed to tune the suspension for various applications. A typical torsion beam setup has a lateral V-shaped beam joining the trailing arms. The Cruze (and other Delta models including Astra and Volt) has a steel tube with a pinched central section, and GM uses a patented helical welding process at the outer ends to connect the beam and control arms. The beam itself provides the roll control function of an anti-roll bar. By varying the thickness of the steel in the tube, the engineers can adjust the car's rear roll stiffness. The tube can also be rotated for different vehicles to change the orientation of the pinched section. By doing this, the roll steer effect of the rear axle (the angle of the wheels as they move up and down that affects the handling of the car) can be changed. A Watts link has also been incorporated to help manage the lateral position of the wheels, the first such application with a torsion beam axle in a production car. A lateral link from the rear end of each trailing arm is attached to the central crank mounted to a sub-frame. As lateral loads build, the linkage puts a counter-acting force on the opposite wheel to keep the whole setup centered under the car.

source: http://www.autoblog.com/2010/04/19/2011-chevrolet-cruze-quick-spin/

Imagine the fact that in essence you could "TUNE" your beam axle for certain forms of competition...

Considering some of the other small cars GM has built with "patented features" I'm just a tiny bit skeptical about their "...patented helical welding process...". Of course, I'm also no engineer, so maybe this won't be another liner-less aluminum cylinder block engine.

My only beef with beam rear axles is their propensity to "jump" sideways when you hit a bump or pothole with the rear wheels. VW does/did a pretty good job minimizing this "fault" in their cars....I hope it works out for GM, too.

integraguy wrote: My only beef with beam rear axles is their propensity to "jump" sideways when you hit a bump or pothole with the rear wheels. VW does/did a pretty good job minimizing this "fault" in their cars....I hope it works out for GM, too.

That's what the Watts link is for (bracket rearward of the wheels, and the two links coming off of it). It keeps the axle centered laterally under the vehicle. I think Chrysler used it on their big SUV's for the last generation.

John Brown wrote: Imagine the fact that in essence you could "TUNE" your beam axle for certain forms of competition...

Well, "you" can't tune the rear end at all. GM can tune it by changing the thickness of metal in the tube, and the rotation of the tube before they weld it to the trailing arms.

So "you" essentially get a beam axle with no tuning ability.

Interesting manufacturing exercise, but not really anything special for an enthusiast end-user.

subrew wrote:

John Brown wrote: Imagine the fact that in essence you could "TUNE" your beam axle for certain forms of competition...

Well, "you" can't tune the rear end at all. GM can tune it by changing the thickness of metal in the tube, and the rotation of the tube before they weld it to the trailing arms. So "you" essentially get a beam axle with no tuning ability. Interesting manufacturing exercise, but not really anything special for an enthusiast end-user.

Yup, cool engineering trick, but really more like a way to make a crappy set up offer almost as much benefit as a decent one. Cool geek stuff, but as an actual car part at best its probably only almost as good as a multilink setup.

subrew wrote:

John Brown wrote: Imagine the fact that in essence you could "TUNE" your beam axle for certain forms of competition...

Well, "you" can't tune the rear end at all. GM can tune it by changing the thickness of metal in the tube, and the rotation of the tube before they weld it to the trailing arms. So "you" essentially get a beam axle with no tuning ability. Interesting manufacturing exercise, but not really anything special for an enthusiast end-user.

Well "I" can barely tune the stereo so "me" tuning the suspension is definitely laughable. I am actually thinking that if the OE builds say 4 different levels of axle depending on OE application for deflection angles but all of identical length someone may buy the "Marshmallow" sedan and build it into the GT-RRR-HAWT coupe with a few minor pieces.

First use of a watts linkage on a torsion beam axle in a production car?? Umm.. no. Pt cruiser and Maxima come to mind.