What Does This Diagonal Strut Do And How Does It Allow Suspension Travel?

[Jeff Bowlsby]

Trying to figure out how the front suspension works, specifically the diagonal strut. The fixed diagonal strut attaches at the bottom of the inboard coil-over shock absorber and to what looks like a ball joint or a throughbolt at the top of the upper A-frame steering knuckle. The strut is either in tension or compression or both, I cannot figure it out from the photos. Being of fixed length and attached at each end, its not evident how the diagonal strut can allow the suspension to travel. The A-frames hinge inboard at the chassis and hinge at the outboard wheel end steering knuckle so the suspension can travel vertically up and down, so by geometry that would seem to require the diagonal strut to lengthen or shorten during suspension travel. But it looks like it is of fixed length?

Can someone who has seen the Elio explain it?

 

[wheaters]

Without the strut the shock wouldn't be connected to the wheel assembly.

The link under the shock will pivot where it attaches to the chassis rail.

 

[JEBar]

Without the strut the shock wouldn't be connected to the wheel assembly.

The link under the shock will pivot where it attaches to the chassis rail.

does it play any part in front end alignment

 

[Gas-Powered Awesome]

The link (pull-rod) is how they get the coil-over assembly out of the airflow to reduce drag and increase MPG. It's an old racer's trick, though there they are worried about top speed, not MPG. Without it, the coil/shock would have to connect to the bottom A-arm near the wheel hub. Look back at the P3 and you'll see it sticking out into the wind.
It won't play any part in steering alignment.

Pull-rod suspension:

 

[JEBar]

It won't play any part in steering alignment.

thanks for the info

 

[Jeff Bowlsby]

I think I see it now, thanks for the insight. I didn't see the link under the shock before, the link allows the movement. The diagonal strut is in tension 100% of the time to transfer chassis weight to the wheel/tire. The coilover shock is mounted to the chassis at the top, but to the link below. Clever. I found this photo of one of the prototypes showing the bottom link laying down almost vertical, and the suspension at its vertical maximum. I think that explains it. Thanks. So extending the length of that diagonal strut lowers the front end without affecting the alignment. :grin:

 

[Gas-Powered Awesome]

So extending the length of that diagonal strut lowers the front end without affecting the alignment. :grin:

And it would retain the stock shock/spring travel. Still limited by A-arm travel, of course, and may not have the best suspension geometry at lower ride heights. Since the Elio will be 5" off the ground to begin with (IIRC), I don't think I will want to lower it any further. I suspect the stock strut would not be adjustable anyway.

 

[Jeff Bowlsby]

I'll be curious to find out if body roll will be an issue in the twisties, I bet it will be, and how easy it will be to fit a sway bar.

At least we'll only need one at the front!

 

[Gas-Powered Awesome]

Peterson Spring is providing the stabilizer bar.
Yes, the stabilizer bar is also known as the anti-sway bar or anti-roll bar.
http://www.eliomotors.com/peterson-spring/

 

[Jeff Bowlsby]

Excellent....