itacud

Here's a Sachs doc describing their variable damping shocks... We get the Pneumatic Damping Control, rather than the cool electronically controlled Continuous Damping Control.

<img src="http://pictureposter.audiworld.com/37958/sachs-pdc-strut-1_aw.jpg"><ul><li><a href="http://www.sachs.de/owx_medien/8/509.pdf">Sachs PDC</a></li></ul>

TheLex

it looks like the airbag/shock is an integral assembly. Therefore we can not change the shock only with an aftermarket one?

That electronic controlled unit looks way cool. Too bad it can't be retrofitted!

HPH

...Those pictures made me think of a question, though. The "rolling lobe" constant-pressure air spring is a clever approach to a variable-height suspension. But the fact that the "fabric" (or whatever it is) of the bladder is folded, or at least bent, would seem to me to be a weak point. You drive around at level 2 (or 1, like I do) all the time, and the bend is at the same place, flexing a little with each bump.

I wonder what the design life-time of these bladders is.

defconfour

...tuned up a bit?

I think some adding some stiffness to the dampeners would help the ride of the allroad out a ton. I notice the float it has a lot more with 245x18's now on it.

RMcQ

Of course mode of failure is quite different. A coil spring just kinda wears out and sags. The bladder could fail in a more abrupt fashion.

itacud

alterable, though it'd probably be expensive to do.

I've talked to at least one shock builder who has taken a stock non-rebuildable shock, cut it open, welded threads onto the body, then changed the oil within.

I'd want to buy a 2nd set of front shocks before doing that, and it'd be expensive. =)

itacud

driving...

The bladders get very crusted with dirt, and I worry that rolling them up and down will be highly abrasive to the airbags. I also worry that the crusted dirt will cause resistance when the bags try to lower themselves by rolling up - this means that air <i>pressure</i> might be lowered some when dropping levels, thereby lowering the spring constant. (If you remember from my posts from long ago, I postulated that barring outside resistances, airbag pressure should remain constant at all spring heights.)

moto-one

I have had two Range Rovers with air ride, with the excption of a softwear problem that left me flat for the weekend, Both went 100k plus with out any problem or excessive wear. Plus this kind of air spring system has been used on over the road trucks and buses for decades.

itacud

Good point! But, how does one explain a "software flat" to friends... ? =)

Ting and CSR

HPH, when you park it for the night, remember to raise to 3 ... And voila! enhanced longevity!