Can air assist suspension soften your ride?

[Lucky]

Personally I doubt that air assist can SOFTEN the ride of a motorhome although it might mask the effects of worn leaf springs and/or dampers. What do you think?

My reasoning is that the softness of suspension through its normal range of travel is dictated by the spring rate (which is not changed when air bags are fitted to replace rubber bumpstops).

Similarly original fit dampers control wallowing and air bags won't dampen the rebound of the spring.

My conclusion is airbags might mask the effect of worn suspension, and definitely will have a major benefit once the suspension travel is consumed (you'd otherwise be hitting the bump stops) but is it being oversold as a panacea to cure all the ills of knackered original equipment?

Personally I fitted air assist to be able to increase ground clearance when accessing my driveway.

I'm no engineer so I'm looking forward to informed input.

 

[ontheroadagain]

I fitted air assist to our motorhome two years ago.
Stability in corners and crosswinds are much improved, but the ride is not softer.
I remember being slightly disappointed by this at the time, but the other benefits make it worthwhile.

 

[jezport]

It is changed with real air suspension. i.e. air springs but not by adding the air bag spring support type.

 

[Hettie's Crew]

Agree with every word. We fitted air assist to our Alko rear end because it was at its limit and the suspension was almost bottoming out, so adding the air bags raised the rear and allowed the suspension to work properly therefore making it a softer, more controlled ride.
Adding air assist to a correctly sprung axle can’t make it softer but may add control.

 

[Landy Andy]

Fitting the air assist did not soften the ride, but made it less crashy, as the air bellows are in constant pressure which will increase under compression.

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[Guigsy]

On our previous van, we were riding on the bump stops (technically spring assistors) all the time. Adding semi-air massively improved the handling. It did make it crash less on pot holes. The improvement it made to general road chatter was mild at best.

 

[wp1234]

I fitted semi air on mine a couple of years ago together with better front springs and personally I think it does improve the ride quality especially on some of the continents rough rods ( Belgium).
On top of that you get the bonus of much better handing around corners/ roundabouts and much more stability in strong winds.

I will definitely be fitting to my next van.

 

[Landy Andy]

I fitted semi air on mine a couple of years ago together with better front springs and personally I think it does improve the ride quality especially on some of the continents rough rods ( Belgium).
On top of that you get the bonus of much better handing around corners/ roundabouts and much more stability in strong winds.

I will definitely be fitting to my next van.

What front springs ? I’m wanting to change mine.

 

[Folkranger]

But it does give quite a bit of levelling adjustment. On my last van I rarely used ramps as I could get about 4" lift to the rear, probably more than the self levelling on my current van.

 

[wp1234]

I fitted Progressive Coil Springs to the .front of the van . Not sure what the make is but I got them from A&L leisure, this is the spiel that came with them.

How Progressive Coil Springs Work
The spring is (for the most part) wound steel and is defined by its rate. Rate is a measurement of the force required to compress the spring and is expressed in lbs per inch. For instance a spring with a 100 lbs/inch rate will require 100 lbs to compress it one inch. Each subsequent inch of compression would require an additional 100lbs of force. This is referred to as a straight or linear rate spring. The alternative is a progressive rate spring which allows a single spring to essentially exhibit multiple rates. By utilizing varied spacing spring coils, the initial rate may be 60lbs/inch, requiring 60 lbs of force to compress it one inch. Then each subsequent inch of movement would require progressively more than 60lbs of force such as 75lbs more for the second inch, 100lbs more for the third inch etc.; Progressive-rate springs become stiffer quicker as they are compressed. The advantage of the progressive spring is that it is supple enough to soak up small bumps, yet firm enough to handle a big hit; providing more comfort during the ride

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[IRHP]

A lot depends on how much air is in them. Anything over 30 psi and you are definitely hardening up the suspension but it cuts down a lot of wallowing on the corners. I even notice a difference when walking around inside the van.

 

[Guigsy]

I fitted Progressive Coil Springs to the .front of the van . Not sure what the make is but I got them from A&L leisure, this is the spiel that came with them.

How Progressive Coil Springs Work
The spring is (for the most part) wound steel and is defined by its rate. Rate is a measurement of the force required to compress the spring and is expressed in lbs per inch. For instance a spring with a 100 lbs/inch rate will require 100 lbs to compress it one inch. Each subsequent inch of compression would require an additional 100lbs of force. This is referred to as a straight or linear rate spring. The alternative is a progressive rate spring which allows a single spring to essentially exhibit multiple rates. By utilizing varied spacing spring coils, the initial rate may be 60lbs/inch, requiring 60 lbs of force to compress it one inch. Then each subsequent inch of movement would require progressively more than 60lbs of force such as 75lbs more for the second inch, 100lbs more for the third inch etc.; Progressive-rate springs become stiffer quicker as they are compressed. The advantage of the progressive spring is that it is supple enough to soak up small bumps, yet firm enough to handle a big hit; providing more comfort during the ride

I'm not convinced by progressive springs. As you said, with a normal linear spring, as for every fixed amount of load you add, you get a fixed amount of travel. But the important thing is that this happens throughout the travel range. The way progressive springs work is the faster bit of the spring effectively runs out travel and binds up, you are left with heavier bits of spring that require more load to compress. This is great if it's a precisely tuned racecar with preloads set. But as your static load changes a lot like with a motorhome, where you are in the travel will change how the spring responds. So if you are heavily loaded, there'll be no supple bit of the spring left and you'll just take hard hits. Whereas a linear spring responds the same throughout its range. Also, dampers are tuned to the spring rate, so you end up with a compromise.

 

[Wannabee]

A lot depends on how much air is in them. Anything over 30 psi and you are definitely hardening up the suspension but it cuts down a lot of wallowing on the corners. I even notice a difference when walking around inside the van.

Me too, well worth the cost and effort.

 

[HugoBNB]

Fitted air suspension on our rear. After a bit of fiddling with bar pressure in it and, adjusting the tyre pressures to the axle weights in line with the Continental tyres website, the ride quality is massively improved. Not to mention some valuable tips off this site too.

 

[Lenny HB]

Can't comment on semi air but our van had a very had ride so we had full air fitted all round. Made quite a difference to the ride and the stability when driving in unbelievable.
I would never have a van without full air now.

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[Coastal Cruiser.]

With E&P you have a choice of modes, Sport or Comfort and it does make a difference in the ride.

 

[wp1234]

I'm not convinced by progressive springs. As you said, with a normal linear spring, as for every fixed amount of load you add, you get a fixed amount of travel. But the important thing is that this happens throughout the travel range. The way progressive springs work is the faster bit of the spring effectively runs out travel and binds up, you are left with heavier bits of spring that require more load to compress. This is great if it's a precisely tuned racecar with preloads set. But as your static load changes a lot like with a motorhome, where you are in the travel will change how the spring responds. So if you are heavily loaded, there'll be no supple bit of the spring left and you'll just take hard hits. Whereas a linear spring responds the same throughout its range. Also, dampers are tuned to the spring rate, so you end up with a compromise.

All I can say is the ride in my van after progressive spring/ semi air addition is much better than factory fit …. for the relatively low cost it’s worth it IMHO .

 

[Phill D]

I softened the ride on our van by fitting semi air on the rear which has given greater stability . but, I also changed the tyres from 215 x 15 to 225 x 15 which allowed me to have non CP tyres with a higher load rating.
This in turn allowed me to reduce the tyre pressures. ( i hasten to add, the pressures are now set at the tyre manufactures recommendation for my loadings )

 

[SSILVO]

I recently had Firestone semi-active on the rear and MAD comfort springs on the front of my Bessacar 442, marginal improvement in the "crashing" on bumps and potholes, however, handling on cornering much improved and straight line on the motorway when being overtaken is excellent virtually eliminated the issue.

ssilvo

 

[Lenny HB]

With E&P you have a choice of modes, Sport or Comfort and it does make a difference in the ride.

I think you have just confused air suspension with hydraulic Jacks.
I think you meant to say VB.

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[Coastal Cruiser.]

I think you have just confused air suspension with hydraulic Jacks.
I think you meant to say VB.

You are correct Lenny

 

[Reallyretired]

Tyre pressures make a huge difference. Mine were originally set to the motorhome label recommendations. Setting to the tyre manufacturers recommendations for the axle load produced a huge improvement.

 

[funflair]

You are correct Lenny

Of course Lenny is correct as you acknowledge Mark and just to be 100% accurate I would also point out that the switchable modes that you refer to are actually in the optional adaptive damping rather than the VB full air itself, the VB full air suspension does have various ride height modes and levelling functions but the adaptive damping itself is another tick on the options list.

 

[pandas]

Of course Lenny is correct as you acknowledge Mark and just to be 100% accurate I would also point out that the switchable modes that you refer to are actually in the optional adaptive damping rather than the VB full air itself, the VB full air suspension does have various ride height modes and levelling functions but the adaptive damping itself is another tick on the options list.

we had VP semi air and it made a big difference to the ride (less bumpy/hard), handling and allowed us to get on and off Italian ferries without bottoming out! However wasn't any good for any type of levelling (which it isn't meant to do anyhow).

 

[Coastal Cruiser.]

Of course Lenny is correct as you acknowledge Mark and just to be 100% accurate I would also point out that the switchable modes that you refer to are actually in the optional adaptive damping rather than the VB full air itself, the VB full air suspension does have various ride height modes and levelling functions but the adaptive damping itself is another tick on the options list.

Didn’t realise that Martin thought the 2 modes were standard with the air.
Very impressed with the Active Air although this being my first van not got any knowledge of the difference it makes.

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[funflair]

Didn’t realise that Martin thought the 2 modes were standard with the air.
Very impressed with the Active Air although this being my first van not got any knowledge of the difference it makes.

I think you only realise when you tick the box and see the £ racking up, standard full air would have the handset but not the buttons on the dash.

 

[EMS]

I have just last week had airbags fitted to our Dethleff Trend but I have not had time to test it on a trip. Our previous van a Hymer 572 Transit improved considerably with a lot less crashing compared to the bump stops (rubber mounts). The van was very quiet when driven, compared to the Trend but this may be due to the weight of the drop-down bed hung from the roof.

 

[minesapint]

I fitted Progressive Coil Springs to the .front of the van . Not sure what the make is but I got them from A&L leisure, this is the spiel that came with them.

How Progressive Coil Springs Work
The spring is (for the most part) wound steel and is defined by its rate. Rate is a measurement of the force required to compress the spring and is expressed in lbs per inch. For instance a spring with a 100 lbs/inch rate will require 100 lbs to compress it one inch. Each subsequent inch of compression would require an additional 100lbs of force. This is referred to as a straight or linear rate spring. The alternative is a progressive rate spring which allows a single spring to essentially exhibit multiple rates. By utilizing varied spacing spring coils, the initial rate may be 60lbs/inch, requiring 60 lbs of force to compress it one inch. Then each subsequent inch of movement would require progressively more than 60lbs of force such as 75lbs more for the second inch, 100lbs more for the third inch etc.; Progressive-rate springs become stiffer quicker as they are compressed. The advantage of the progressive spring is that it is supple enough to soak up small bumps, yet firm enough to handle a big hit; providing more comfort during the ride

I have fitted Air Assist suspension on our last three motorhomes, and as others have commented, it gives a better ride, less wallow with less suspension banging. It is also a great help when levelling up on the pitch, you can as others have said level up side to side or front to back or both. Also when walking around in the van, I put extra air in on site to make the van more stable. Great bit of Kit and easy to fit.

 

[tigerblue]

I had rear air-assist suspension fitted to our 2019 Citroen van. Made a world of difference in my view. Better stability, less rolling on roundabouts, no crashing from potholes and no rear end sagging. Worth every penny IMHO.

 

[Wyvern]

VB airbags are NOT air suspension. They are more than bump stops in that they help with wallow and weave for higher speeds.

However, if you van is bottoming out, these things should not be used to stop that. You should get the suspension resolved, possibly another leaf spring.

What they are thereto do is compensate the shocks. Shock absorbers have to deal with a wide variety of load and conditions. If they were set to deal with the highest load then you ride would be harsh when light loaded and visa versa.

The airbags are great as they help compensate for the extremes.

If you rely on them to stop you bottoming out then you are placing pressure on you chassis where it is not designed to go.

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