Air suspension ride height and pressure.

[RyCam]

I have previously fitted Dunlop air assist to my Swift Escape 674 rear Alko Axle which I would recommend for a smooth stable drive.
As my van is low to the ground as standard, I have had a few occasions where the water tanks have contacted the ground and speed bumps etc. For this reason I have now fitted 40mm front suspension strut spacers to gain ground clearance. To gain the same lift on the rear axle I need to inflate the air bags to approximately 6 bar which I believe to be far to high for normal driving conditions and would remove the movement from the suspension.
The Dunlop air bags have a 15mm nylon spacer plate fitted under the bag as standard, my thinking is if I could install deeper spacers this would achieve the same lift but with less pressure in the air bags.

Has anyone done this before? does anyone foresee any issue assisting the Alko axle in this way?
Any feed back is more than welcome

 

[Landy Andy]

I’d be careful of exceeding the travel that your standard suspension is designed to do.

Most of us fit air assist to bring our vans back to within the standard range.

Sounds like your van is very very low. And I wouldn’t run my bags with 6bar continuously.

 

[oldiesontour]

Theoretically fitting a thicker spacer will not make any difference...as it won't make the van any lighter so will still take the same air pressure to lift it...it will only reduce the volume of air required as the bags won't be extending as far( unless at 6 bar you are stretching the bags )

 

[RyCam]

Theoretically fitting a thicker spacer will not make any difference...as it won't make the van any lighter so will still take the same air pressure to lift it...it will only reduce the volume of air required as the bags won't be extending as far( unless at 6 bar you are stretching the bags )

The van starts to rise at approximately 1.5 bar, at 2.5-3 bar she sits about 20mm higher than standard. To achieve the 40mm to match the front I need 6 bar. This is why I was thinking if i replaced the 15mm spacer plate with a maybe 35mm spacer, the van would the rise up into the desired height at a lesser pressure and not stretch the bags so much

 

[oldiesontour]

My boxer is up by the 40mm you want at 2 bar.But it's easy enough to try as a temporary test stationary by adding a bit of hard wood or steel

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[RyCam]

My boxer is up by the 40mm you want at 2 bar.But it's easy enough to try as a temporary test stationary by adding a bit of hard wood or steel

Is the Boxer running an Alko axle? or leafs

 

[DerryW]

Not having experience of Alko chassis/axle, I’m not sure how difficult it would be for you to fit said spacers to see if 2-3 bar would give you the answer you’re after.

Must confess I’m not a skilled mechanical engineer. So only a suggestion.

Good luck anyway, I’m sure there’s a solution out there for you.

 

[oldiesontour]

Is the Boxer running an Alko axle? or leafs

Leaf

 

[Scottish Scrutineer]

IIRC the Alko is torsion bars, with your additional air to assist. If so, you need to start by adjusting the torsion bars to raise the ride height, then add either increase the spacers so the air bags are inflated to the similar length as at present, or accept that the air bags may reach full extension which could limit their lifespan. The air is to assist, not do the heavy lifting.

 

[RyCam]

IIRC the Alko is torsion bars, with your additional air to assist. If so, you need to start by adjusting the torsion bars to raise the ride height, then add either increase the spacers so the air bags are inflated to the similar length as at present, or accept that the air bags may reach full extension which could limit their lifespan. The air is to assist, not do the heavy lifting.

I got the below response direct from Alko when i asked if the angle could be adjusted to provide more ground clearance. My van has the triple torsion bar set up. I am aware some other can be adjusted - Can the triple bar system be adjusted?

Hi Ryan,
The axle fitted to this chassis is set at 15°.
ALKO advice would be that the angle of the swing arm should not be changed. Changing the swing arm angle is not something ALKO would ever advise could be done, all ALKO axles are preset during the manufacturing process of the axle. Different axles are available at different angles, and this may also result in different shock absorber set ups being required.
The most suitable option would be to add air suspension to increase the ride height, the customer should speak with VB air Tel: 01254 848010.

Regards
AL-KO KOBER LTD
South Warwickshire Business Park
Kineton Road
Southam
Warwickshire
CV47 0AL
www.alko-tech.com/uk