Vans with air springs

[Graeme]

I know there are air suspension systems for trailers and vans including options to auto load level but the ones I've encountered don't have much travel because of the design of the air spring. Do trailer/van air springs exist that have enough travel to be used at 50mm above their normal operating height, or could be set 25mm lower than usual for normal use and then be used 25mm higher than usually to obtain a 50mm overall height increase?

[Hoges]

should be possible... try Airbag man (http://www.airbagman.com/)

[Graeme]

Thanks Hoges. I've since done some more looking and there are plenty ex USA.

I'm thinking ahead in case I decide to replace the suspension on a older van and wondered if the van could be raised for use with the D4's variable height suspension, rather than use steel springs for a set height.