Air suspension?

[Pete-B]

Hi, I've got the EP automatic levelling fitted to our Bessacarr E462 which is a great system and I'm very pleased with it.

 

I'm now wondering, is it worth spending a further grand, or a little over, to have the semi automatic VB air suspension fitted to the rear?

 

I would appreciate any comments from anyone who has this system.

 

Thanks.

[Derek Uzzell]

Details of 2015 Bessacarr E462 in this advert

 

http://viscountmotorhomes.co.uk/listings/2015-bessacarr-e462/

 

The E462 is based on Fiat’s camping-car chassis (not on an AL-KO chassis) and I think the VB product shown here would be applicable

 

https://www.vbairsuspension.com/upload/File/Productbladen/Engels/EN_SemiAir__PFC_X250_Auxiliary_air-suspension_v1.0_-_721155180720_LR.pdf

 

As far as I can make out this system has no automation. As it says on the link, it allows a driver to level a motorhome ‘statically’ when it is laden heavily or unevenly - and would allow a motorhome’s rear end to be raised for increased rear ground-clearance when entering/leaving a ferry - but the system would not automatically and continuously adjust the ride-level of the motorhome while it is being driven. For that VB’s FullAir rear-axle air-suspension system would be needed.

 

I can’t tell you whether it would be worth (financially or technically) having VB’s SemiAir system fitted to your E462, but there are similar systems that include a 12V compressor that are likely to be significantly cheaper. Example here

 

https://www.ebay.co.uk/itm/AIR-SUSPENSION-KIT-with-12V-Compressor-Fiat-DUCATO/182830416388?hash=item2a918ac204:g:5VgAAOSwPcVVyw9Z

 

 

[witzend]

I fitted the above ebay link kit myself and it's been fine for 3+ yrs and 35,000 mls I did not have the compressor and fitting took 2 hrs on my drive with rear of van on leveling ramps so easy job for a garage

[Pete-B]

 

Hi, further to my original posting and I appreciate this is not the main reason to have semi air fitted, but does it make any difference to ride quality, ie, is it a softer ride?

 

Thanks.

[witzend]

Pete-B - 2017-11-05 5:36 PM

 

 

Hi, further to my original posting and I appreciate this is not the main reason to have semi air fitted, but does it make any difference to ride quality, ie, is it a softer ride?

 

Thanks.

Not that I've noticed just lifted my tired springs

[Derek Uzzell]

Pete-B - 2017-11-05 5:36 PM

 

 

Hi, further to my original posting and I appreciate this is not the main reason to have semi air fitted, but does it make any difference to ride quality, ie, is it a softer ride?

 

Thanks.

 

A vehicle’s ride quality will depend on a number of things - the design of its suspension, its tyre pressures and the load being placed on its axles are just some of these.

 

This Practical Motorhome article summarises potential benefits of suspension upgrades:

 

https://www.practicalmotorhome.com/advice/32011-air-assist-suspension-explained

 

The 1st attached photo is of the rear suspension of a Ducato ladder chassis. The springs are parabolic type and (in the example) each spring has two leaves, but there are now three alternative specific springs available for the Fiat ‘camping-car’ chassis used on motorhomes, including a weight-saving composite-material spring.

 

Above the axle is an orange bump-stop/spring-assister and (In the photo) there clearly is a wide air-gap between it and the spring. Adding air-assist involves replacing the orange component with a rubber bellows-unit (as shown in 2nd attached photo) into which air can be pumped.

 

Provided that an air-gap remained between the bump-stop and the spring when a motorhome was being driven, adding air-assist would not improve the ride quality and, as the bellows would be adding extra ’springing’, the ride would become firmer. However, if the weight on the motorhome’s rear axle were such that there were no air-gap and this was contributing to a harsh rear-axle ride quality, fitting air-assist should be expected to improve matters.

 

My 2015 Rapido motorhome is based on a Ducato camping-car chassis and has single-leaf rear springs. Its fully loaded stance is noticeably ’tail up’ and there’s an air-gap between the bump-stop and spring. I’ve lowered the Fiat recommended front and rear tyre-pressures by 0.5 bar as the original ride quality was somewhat harsh for my liking. Adding air-assist should not improve my Rapido’s ride quality and inflating the bellows would unaviodably raise the vehicle’s rear end even higher. To deliberately soften the Rapido’s rear suspension would involve a different approach and, if I really wanted to experiment, I’d fit Koni FSD dampers.

 

https://www.koni.com/en-US/News-Events/News-Releases/New-product-release-FSD-for-Fiat-Ducato-camper/

 

which would cost between £400-£500 for a pair of rear dampers.

 

It’s doubtful though that I’d end up believing the exercise had been financially worthwhile, as I don’t find the Rapido’s ride too bad now I’ve lowered the tyre pressures. 50 years ago I used to play about with my cars’ suspension, but the only way to be sure of the effect was to make the modification and drive the vehicle.

[Brian Kirby]

Pete-B - 2017-11-05 5:36 PM

 

 

Hi, further to my original posting and I appreciate this is not the main reason to have semi air fitted, but does it make any difference to ride quality, ie, is it a softer ride?

 

Thanks.

Taking into account Derek's comments above, but based on my own experience of a van with air assistance fitted, I would say "more compliant" rather than "softer".

 

The van to which I fitted air assistance was Transit based, but had a longish rear overhang, meaning that, although comfortably within its maximum rear axle load limit, the rear was prone to grounding. This somewhat tail down stance also, as Derek says, meant that the plastic spring assisters were in permanent contact with the stop when the van was fully laden.

 

I pressurised the air suspension bellows so that the laden rear ride height was the same as the unladen rear ride height. This reduced the grounding risk, reduced roll somewhat (the two bellows were separately inflated, so not interconnected), reduced a slight sense of rear yaw (especially noticeable on roundabouts), and gave a better damped, more compliant, and more directionally stable, ride overall.

 

However, those gains were dependent on the peculiarities of the van design plus the Transit rear suspension design. I wouldn't assume the same results would translate to anything other than a very similar van on the same base vehicle chassis. Different layouts, with different rear overhangs, with different rear suspensions, must be expected to yield different results.