Air suspension for adjustable ride height

[skyking]

Originally Posted by JulianEdgar

What are these? I know Porsche run them but I've not seen them in the aftermarket.

Edit:

Interesting, but I don't think I'll fit that under the Insight! What's inside the housing? A dog clutch and cam?

some sort of driven coupler.

[JulianEdgar]

Originally Posted by Taylor95

So what changes have you made to your steering with your adjustable air suspension?

A common problem with lifted Jeeps is death wobble, which happens when a lift is installed without adjusting the trackbar and/or control arms. How would a system like this work without causing any tire wobble?

Shimmying is much less likely with independent suspension than with solid axles, so Jeeps with solid axles (obviously, that's not all Jeeps) will be more susceptible to 'death wobble'.

However, one area to be very careful of is change in toe with change in ride height. This is also known as roll steer, because when cornering, one side of the suspension compresses, and if this causes a change in toe, it will give a change in steering.

The Insight has very little front toe change with bump and rebound - basically none that is measurable. However, because I control the front springs individually, I can still very occasionally feel a tiny steering effect when one of the front springs is altering in ride height. Controlling the front springs as a pair would get rid of this.

At the back it is more complex. When I ran at max height, I could feel distinct rear roll steer effects on turn-in. The rear torsion beam suspension was giving toe-out in roll to the outside wheel, and this was quite noticeable - it made the car feel like it was oversteering on turn-in. I then remade the torsion beam pivot brackets, lowering the height of the pivot points. This fixed the issue.

Modified rear suspension pivot bracket before painting:



So making the car behave with height adjustable suspension is very dependent on the car in question.

[skyking]

Yes, with my live axle truck I will have to be very careful about what the geometry is going to do at different heights. It will ultimately limit my maximum adjustment.
One thing to consider, is I would tune for best behaviors at lower heights. That would be on-road behavior.
I would only raise it up as needed for clearance at very low speeds, crawling really.

[Taylor95]

Originally Posted by JulianEdgar

Shimmying is much less likely with independent suspension than with solid axles, so Jeeps with solid axles (obviously, that's not all Jeeps) will be more susceptible to 'death wobble'.

However, one area to be very careful of is change in toe with change in ride height. This is also known as roll steer, because when cornering, one side of the suspension compresses, and if this causes a change in toe, it will give a change in steering.

The Insight has very little front toe change with bump and rebound - basically none that is measurable. However, because I control the front springs individually, I can still very occasionally feel a tiny steering effect when one of the front springs is altering in ride height. Controlling the front springs as a pair would get rid of this.

At the back it is more complex. When I ran at max height, I could feel distinct rear roll steer effects on turn-in. The rear torsion beam suspension was giving toe-out in roll to the outside wheel, and this was quite noticeable - it made the car feel like it was oversteering on turn-in. I then remade the torsion beam pivot brackets, lowering the height of the pivot points. This fixed the issue.

Modified rear suspension pivot bracket before painting:



So making the car behave with height adjustable suspension is very dependent on the car in question.

I think that making this change to a solid front axle vehicle would require swapping to IFS, unfortunately. IFS seems much better suited for altering the amount of lift like an air suspension setup would do.

However, I would expect a solid rear axle to perform much better than an IRS.

The ideal set up would probably be a solid rear axle with IFS and with an electric rack and pinion steering.

[JulianEdgar]

Originally Posted by Taylor95

I think that making this change to a solid front axle vehicle would require swapping to IFS, unfortunately. IFS seems much better suited for altering the amount of lift like an air suspension setup would do.

However, I would expect a solid rear axle to perform much better than an IRS.

The ideal set up would probably be a solid rear axle with IFS and with an electric rack and pinion steering.

I don't really know - I've never played with solid axles, except as a lightweight front beam on a tadpole Human Powered Vehicle (recumbent trike).