Semi Air Suspension

[stevemc67]

Advice please. Recently swapped previous vehicle for a 2019 Elddis 155. Base vehicle 2.0 ltr Euro 6 Boxer, 130bhp. I am considering rear semi air, mainly from the stability and handling aspect. What i’ve noticed when researching is that one of the benefits of the system is increased ride height. This is the bit I’m having difficulty with! As the vehicle is nearly new the suspension is still “stiff” and on a level pitch I have to run on to the 1st pocket on the level up ramps to be level front to back. Hence in normal driving mode the back is slightly higher than the front. So, comments on the following would be appreciated:

1. Is the increased ride height only when the system is pumped up ?

2. Are these systems primarily for higher mileage vehicles whose suspension may have “sagged”?

3. When fully deflated would the level revert to normal ? i.e. bump stop height.

4. Are their any base vehicle warranty or vehicle insurance implications?

 

Finally any feedback on SAP of Doncaster re. supply and fit of the VB system would be useful.

 

Thanks.

[Keithl]

Hi Steve and welcome,

 

Sorry but I can't comment on fitment to a Boxer but I can tell you that you are not intended to run the system un-inflated!

 

I have the Dunlop system from Marcle Leisure fitted to a Merc Sprinter chassis and the instructions clearly state "Minimum Pressure 0.5 bar" (~7 psi). I run at 40 psi for normal use and this does give a small increase to rear suspension height.

 

Keith.

[blaven]

Certainly on my Dunlop rear conversion, when you let the air out it reverts to original height. Remember, you are not replacing your rear suspension, you are merely introducing a collapsible air bag between the chassis and the axle (if that’s the system you’re contemplating). It’s transformed the ride and handling of my 2003 Ducato.

I carry a compressor to pump back up if I need to let the air out, and remember, you need to let the air out if you have a rear puncture and need to jack up using the chassis jacking point.

[peterjl]

I thought all Moho were front down. I alway drive up hill on any pitch incline which often

offer puts us level.

 

All my 6 Moho,s have been like that.

 

Peter

[Derek Uzzell]

Steve

 

Historically, fitting air-bellows (‘semi-air’) was commonly done to compensate for an older motorhome’s rear leaf-springs having become tired resulting in the vehicle’s rear end starting to sag. Also, when a motorhome is being weight-uprated, fitting semi-air increases the capability of the rear springing to cope with additional load being placed on it.

 

If a motorhome is sitting heavily on its rear bump-stops, once those bump-stops have been removed and been replaced by air-bellows, the rear ride height may not increase. But otherwise, as the air-bellows must not be operated with zero pressure in them, it should be expected that - if there is no change in the load being placed on the rear axle - the rear ride height will rise, and the higher the pressure in the air-bellows, the more the rear ride height will go up. Plainly, if there is no air in the bellows that’s equivalent to the bellows not being present and, if the bump-stops were not being compressed prior to the air-bellows being fitted, the ride height will be whatever it was originally.

 

There are potential warranty implications as retrofitting semi-air won’t be authorised by Peugeot. So if the installation is not carried out properly and damage results, or a mechanical failure occurs (say a broken spring or failed damper) during the motorhome’s warranty period, Peugeot MIGHT blame the semi-air system for this. It’s doubtful that an insurance provider will have reservations about fitting semi-air, but a telephone call to your provider would confirm this.

 

Fitting semi-air will normally be done to address a shortcoming like ‘sag’ or to augment existing rear springs that will need to deal with a higher-than-original load. When motorcaravanners have retrofitted semi-air and subsequently praised its positive effect on stability and handling, it needs to be borne in mind that the task was carried out for a reason - like the motohome lacked stability or handled poorly.

 

I’ve idly considered fitting semi-air to my Rapido, but as the vehicle does not sag at the back, handles well and is pretty stable even in strong cross winds, I really can’t justify the £300-£400 cost of what would be a ’tuning' experiment, particularly as the Rapido already rides tail-up and air-bellows would exaggerate that stance.

 

However, having looked at pictures of an Elddis Autoquest 155 (image attached below) it seems likely that fitting semi-air to that model would be worthwhile stability/handling-wise as the 155 has a significantly long rear overhang. I would have thought you should get some worthwhile improvements without the rear ride height increasing much, but if you opt for a system that includes a compressor (example here)

 

https://www.rhinoinstalls.co.uk/vb-semiair---x250--x244--2002---current--fiat-ducato--citroen-relay--peugeot-boxer

 

if you so chose you could easily alter the bellows’ inflation pressures for when you were parked up.

 

(I doubt there will be any noticeable ‘give’ in your motorhome’s rear springing in the short term - after 4 years my Rapido’s rear ride height is the same as it was when I bought the motorhome.)

[Yorkyrunner]

Just had towbar and Airassist fitted by a recomded fitter near Preston as the rear overhang on the K yacht is quite long and as I load up in the garage and put ebikes on rear rack it seemed the right thing to do It sit a couple of inches higher so the use of front levelers has come into play.

[weldted]

I have an Elddis Aspire 255 (2012) to increase my payload to 3850 kg I fitted semi air to the rear axle. Quite straight forward around two and a half hours. Luckily I keep my van in my garage so have a nice level floor to work from. I emptied the van of all the usual clutter then measured the height from the rear jacking points to the ground. Removed the bump stops fitted the air bags reloaded the van weighed it at 3830 kg. then measured and again pumped it up to the same height 2.3 bar.

Increasing the bags to 2.7 bar raises the van by a further app 25 mm. Ride is much better more stable on bends. To get the extra payload over the rear axle 2240 kg I had to increase the tyres from 217/70 R15 to 225/70 R15.

[Derek Uzzell]

weldted

 

I remember the peculiar handling problems that your motorhome exhibited after semi-air had been fitted and the vehicle’s rear tyres replaced.

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Oversteer/48778/

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/mixed-tyres/49182/

 

I’m not sure if Steve would want to fit semi-air to provide a weight upgrade as well as (potentially) improving his motorhome’s handling and stability, but your experience shows that what one might expect to be an uncontroversial and beneficial modification can occasionally produce unpredictable and negative behaviour.

[skaman]

Check out Aeon rubber springs.

 

I have them fitted on a 4500 kilo Hymer on a sprinter chassis which used to wallow around a lot before they were fitted.

They made a massive difference.

Easy to fit as just go in place of the bump stops, and not expensive to buy.

Much much larger versions are fitted to trains.

 

The best solution is quite often the simplest and not expensive high tech.

[Derek Uzzell]

A 2019 motorhome based on a Peugeot Boxer ‘camping-car’ chassis will have as standard rear bump-stops that have qualities akin to Aeon springs. This webpage

 

https://www.sospensionieasytop.it/en/catalogo/4~peugeot/peugeot-boxer-x250-dal-2006-iii-serie.html

 

relates to fitting an “EasyTop” semi-air kit to a recent Boxer. The standard bump-stop can be seen in the top-right photo and its removal is shown in the installation video.

 

Your Hymer motorhome wallowed a lot (a common complaint with earlier Sprinter-based models that had a narrow track and soft springing) and installing Aeon springs addressed that behaviour successfully.

 

But the snag with fitting non-adjustable supplementary springing (whatever its type) is that, once in place, the motorhome’s owner is stuck with the result. If Aeon springs were fitted to Steve’s Elddis and this raised the rear ride height significantly, or unduly stiffened up the rear springing, there would be nothing he could do about this.

 

I’m not certain whether Steve is considering fitting semi-air to his Elddis because the motorhome lacks stabiliity and does not handle as well as he would like, or if he is happy enough with the motorhome’s stability/handling but thinks that fitting semi-air would be a worthwhile enhancement. But, either way, semi-air should allow him to ‘tailor’ the firmness of the vehicle’s rear springing and adjust its ride height, whereas non-adjustable supplementary springing will not.

[stevemc67]

Many thanks for all responses, particularly Derek’s in depth analysis. I think I’ve come to the conclusion that potential negatives outweigh potential positives at the moment!

[Dickybeau]

I have a 2015 Bürstner and recently fitted Euroair auxiliary air bags.run them around 1 bar but a bit more the closer I get to 4000kg. I haven’t noticed any difference in ride height. In fact, the advice from euroair was to inflate them to level the van off. If I were to run them at 2 bar, the ride would be too harsh and 3.5 bar is the recommended max fir that product. Fiddly to set the correct air pressure but worth the fitting imo.

[Derek Uzzell]

Yes, but your decision to fit ‘semi-air’ was to prepare for uprating the gross weight of your motorhome (built on a Fiat Ducato ‘light’ chassis) to 4000kg as discussed here

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Euroair-auxiliary-suspension-on-B-rstner-A-Class/51749/

 

The attached image is of a 2015 Burstner i700 model. This was commonly marketed with a gross weight of 3500kg and usable payload was not large. The vehicle in the photo seems to sit slightly nose down, but loading up the rear garage with heavy ‘stuff’’ would inevitably reduce the rear ground clearance to some degree. So you actually needed semi-air on your motorhome due to the weight uprating.

 

If Steve planned to carry out a similar weight uprating exercise, he’d almost certainly also need to fit semi-air to his Elddis’s rear axle. But with the Elddis still being ’tail up‘ when loaded, it’s questionable whether fitting semi-air now would provide value for money. Retrofitting semi-air is normally a straightforward procedure that could be done at any time during the Elddis’s lifespan, so there’s no real rush. If it becomes plain to Steve that the Elddis’s stability/handling would improve from fitting semi-air, he can have it done at that point knowing that it will be worth the expense.

[stevemc67]

Thanks again for the comments.

Derek, your final paragraph response is spot on! So given your earlier thoughts I think it’s a case of “if it ‘ain’t broke don’t fix it”. I had actually toyed with an uprate given I have C1 entitlement allied to c£100 reduction in VED. However, in light of comments in another live thread I was probably being too simplistic on the VED front. I suppose the real clincher at the moment is the uncertainty re. base vehicle warranty. I’ll most likely review once it’s expired.

Once again, many thanks.

[Dickybeau]

Interesting point Derek but I never loaded the van enough to drop it on to the bump. In fact, I can’t see me approaching 4000kg even when fully loaded with all my stuff (and I brought back around 8 dozen bottles of wine this year). The thing I have noticed is that I have less wiggle when passing artics with the airbags fitted. Something that others have commented on. The ride on partial or full load is smoother and quieter from the back end. Empty it’s just as noisy and crashing as it always was. The bump stops don’t connect the axle to the body (since they leave a space that uneven road surfaces and sagging springs reduce)whereas the airbags do. I suspect that has something to do with the ride changes. YMMV.

[Derek Uzzell]

stevemc67 - 2019-08-16 2:16 PM

 

...I had actually toyed with an uprate given I have C1 entitlement allied to c£100 reduction in VED...

 

My 2015 Rapido is built on a Fiat Ducato ‘light’ chassis and I could have ordered the vehicle with a gross weight of 3500kg or (at no extra charge and with exactly the same technical specification) 3650kg. As I have not held a C1 driving-licence entitlement for 5 years, I chose the 3500kg option.

 

My motorhome’s Fiat VIN-plate shows a gross weight of 3650kg, but this is overridden by the 3500kg figure shown on the Rapido VIN-plate. The current VED annual charge for my 3500kg motorhome is £265; if I’d specified that it have a 3650kg gross weight that charge would be £165. Your Elddis is built on a Peugeot Boxer chassis, but it wouldn’t surprise me if the same 3650kg or 3500kg alternative weights are available.

 

If your objective is just to save £100 per annum on VED, you could explore with the DVLA what a motorhome owner needs to do to uprate on a DIY basis a motorhome’s gross weight by a small amount (say 3500kg to 3650kg) so that it moves from the PLG VED class to the PHGV class. No ‘mechanical’ modifications should be necessary, so there should be no warranty implications, nor should there be any potential impact on UK speed limits as the motorhome’s unladen weight won’t have been altered.

 

I don’t recall anyone seeking to uprate a motorhome’s gross weight purely to gain a reduction in VED, but there’s no obvious obstacle to that ploy being attempted. The snags are that an over-3500kg weight has speed-limit implications when driving outside the UK, the motorhome may be harder to sell subsequently and the DVLA nowadays may be less accommodating than they used to be about the uprating exercise being performed by a private owner. This 2018 forum thread refers

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Weight-upgrade/50266/?DisplayType=nested&setcookie=1&go=Go

 

In this more recent discussion on another forum

 

https://motorhomer.com/threads/oh-dear-i%E2%80%99m-overweight.38749/

 

the statement is made

 

"the DVLA would not update the vehicle records unless they had a report from a recognised, competent engineer”

 

If that’s now a hard-and-fast rule, then uprating (or downrating) a motorhome’s gross weight - even if this is only involves a ‘paper exercise’ - can be expected to cost around £200 if an agency is used to middle-man the process. It MIGHT be possible to DIY the procedure, but it would be wise to take into account the cost of the military-grade tranquilisers needed when conversing with the DVLA.

[monique.hubrechtsgm]

OK there we go again on plate weight. Total and axle loads No more no less. In belgium you pay the mot according the plates technical. Not by licence driver. And the tests are different for 3500-3650-3850-4000. On a fiat light single rear axle. The standard ride height of a vehicle is relative and have a tolerance of 1 cm. And it defined as: Center of the wheel axle vertically To the underside of the WHEELARCH. full liquids no extra.

[stevemc67]

Thanks again Derek. Comment re. Tranquillisers duly noted !!!!!!!!!

[monique.hubrechtsgm]

Semi air suspension on the fiat rear axle is mostly their to solve weight problems. To prevent the wheel arches come into contact whit the wheel. This has nothing to do whit the real thing It act as a a soft bump stop.