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Discussion Starter #1
I'm running a standard height SWB T28 on (as far as I know) stock shocks and springs. I had the rear springs replaced earlier this year as a pair by VW due to an MOT fail (pig tail broken). Shortly prior to this I'd had a RIB Altair seat fitted, so there's more weight permanently in the back. The rear no longer sits level and the ride feels more vague since these events. Used in earnest (fully loaded with bikes on the back) cornering on Scottish single track required more care than in the past (though I'm sure a Khyam in the roof box didn't help).

I'm attributing the change in handling to the additional weight distribution in the back and I'm considering Air-Lift bags in the rear springs to settle things down. I'd like to hear from anyone using them, particularly on a T5.
  • Are you using a control kit, or just the bags and a pump?
  • Where have you mounted the pump valve?
  • Is a control kit worth the money? Much as I like the gizmo look of a WirelessONE for example, in reality I'm not going to be adjusting it that much, so it would be more of a shiny pressure gauge most of the time. Anyone just using bags and wishing they'd gone for a control kit, or using an in-line pressure gauge only?
  • What sort of PSI range do the bags run at when loaded? (I know the gauges run up to 200 but 90 PSI on bike tyres feels pretty hard to me)

...and can anyone tell me why MAD Suspension bags are 3-4 times more expensive than Air-Lift?

Any other thoughts/comment welcome

Thanks
 

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Hello! I'm probably a bit biased but it does sound like the red bags that fit into the springs would help.

The majority of people just fit them with the included Schrader valves and top them up as and when, the controllers are handy if you're loading/unloading a lot, and in fact they're handy at the start when you're playing with pressures to find the right balance but certainly not a necessity as you can just check the bags when you check your tyres, that kind of thing.

The pressures on these go up to 25PSI but I think anywhere between 8-15 is about normal, the gauges on the load support controllers go to 100PSI but that's because they work with a variety of different bags.

With regard to mounting if you were to go for an onboard controller, I'd personally try and fit the compressor in the boot or under the bonnet. They're reasonably splash proof so long as they're not getting completely soaked, you'll probably want to fit it fairly far from earshot although the compressor doesn't run for long on these bags so it's probably not an issue.
 

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Discussion Starter #3
Thanks Jonathan, that's a very honest response, particularly re need (or not) for controls. I'll be in touch!
 

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Hello! I'm probably a bit biased but it does sound like the red bags that fit into the springs would help.

The majority of people just fit them with the included Schrader valves and top them up as and when, the controllers are handy if you're loading/unloading a lot, and in fact they're handy at the start when you're playing with pressures to find the right balance but certainly not a necessity as you can just check the bags when you check your tyres, that kind of thing.

The pressures on these go up to 25PSI but I think anywhere between 8-15 is about normal, the gauges on the load support controllers go to 100PSI but that's because they work with a variety of different bags.

With regard to mounting if you were to go for an onboard controller, I'd personally try and fit the compressor in the boot or under the bonnet. They're reasonably splash proof so long as they're not getting completely soaked, you'll probably want to fit it fairly far from earshot although the compressor doesn't run for long on these bags so it's probably not an issue.
I have this problem when fully loaded and tow bar plus. 4 bikes cantilevered off the back . I have lowered suspension 40mm but its at least 60 now I would say, even without any load. I was told they were suited to my t32, but I am really worried about fully loading for holiday in 2 weeks. I also want a softer ride , do the bags help or hinder this? should I just put sportlines springs on the back.?
 

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Discussion Starter #5
I have this problem when fully loaded and tow bar plus. 4 bikes cantilevered off the back . I have lowered suspension 40mm but its at least 60 now I would say, even without any load. I was told they were suited to my t32, but I am really worried about fully loading for holiday in 2 weeks. I also want a softer ride , do the bags help or hinder this? should I just put sportlines springs on the back.?
I ordered a set of bags which arrived yesterday - top marks for speed and service from Air-Lift :clap They're simple and look straightforward to fit, just need to get the bus up on the ramps and work out where to locate the valve. Hopefully Jonathan can comment re ride quality, I'll post back when I've had chance to fit and evaluate.
 

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I ordered a set of bags which arrived yesterday - top marks for speed and service from Air-Lift :clap They're simple and look straightforward to fit, just need to get the bus up on the ramps and work out where to locate the valve. Hopefully Jonathan can comment re ride quality, I'll post back when I've had chance to fit and evaluate.
Jonathon. How does it effect an already hard suspension, i dont want it to feel lkie there is none!
 

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Discussion Starter #8 (Edited)
An update for Dracs and anyone else looking at this issue in the future.

I fitted a set of Air-Lift bags and I'm pleased with the initial results which are very positive T: Rear sag has gone (it's lifted about 30mm and now sits level) and road manners are improved, particularly corners and traffic calming bumps. I haven't tried it all-up with bike racks as yet, but a non-scientific field test (100kg of me bouncing on the tow bar) gave a good, measured bounce with no bottom-out or pogoing. The bags basically act as inflatable bump-stops, so the ride is a bit like that of compressing a held football. I wouldn't describe it as hard at all Dracs. Fitting to lowered coils might be a bit more interesting though with less clearance to wiggle the bags into?

Here are a few photos for anyone interested:

The kit. Pretty simple - two bags, tubing, T piece, clips, zip ties and a Schrader valve (actually there are two valves supplied, so you can fit and control the bags independently if you wish. Mine are teed together). There's a flexible plate and jubilee clips to protect pipework from the exhaust, but I didn't need it.



The problem, pre-install. Not a lot of room between bump stops...



To install, you squeeze all of the air out of the bags to get them flat enough to slide between the coils (tip - squeeze them flat then put the dust cap back on the nipple to keep them at partial vacuum, otherwise they spring back into shape). Jack the van body up so that the wheels drop and the suspension coils open up.



I ran the pipework along the hand brake cables, teed them together where there's a hole in the underplastics then ran a single line behind the plastics to the rear bumper. The style conscious colour-coded amongst you could hide the valve underneath (e.g. downwards from a rear plastic), and I may do this when the bumper gets replaced. For now I'm going to rock the 'inflatable van' look. The kit doesn't come with dust caps (which is a bit odd), so you'll need to raid your bike kit to find one and protect the valve opening.



Inflated bags in place. This is at 25psi, under load with the van back on the ground. I'll be experimenting with lower pressures (and get around to re-applying Waxoyl on those wishbones and roll bar)



...and closeup of the bag against the upper bump stop. There are warnings in the instructions (aimed at Dodge applications) about ensuring your turrets are filed smooth. No issues with my turrets, but I wonder what the effect of rubbing might be over time? I may experiment with putting an exhaust doughnut up top to help distribute the load and to provide a buffer between the metal and the bag.



#
 

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Discussion Starter #9
Prompted by a PM query, a quick update on my install and experience with Air-Lift bags:

They're still fitted and still working well after 2.5 years, pretty much fit and forget. I've occasionally checked pressure but the PSI involved is so low I've not encountered pressure loss. They've lived up to expectations and make a big difference in laden handling to reduce rear shimmy on bends and eliminate bottoming out. With bikes on the back the transformation in handling is even more marked from how it felt before fitting T:

I haven't removed them completely for inspection, but I checked them in November 2015 while the rear was jacked up to put winter wheels on - no discernible signs of wear. As I indicated in OP, I added a rubber exhaust donut at the top of each bag to act as a wear buffer and load distributor against the metal turrets. The only visible wear to the system has been corrosion to the inflation valve stem which I'll be addressing with a dab of Kurust and paint.

So, initial results and impressions have been born out over time - well worth the investment imho
 

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Hello! I'm probably a bit biased but it does sound like the red bags that fit into the springs would help.

The majority of people just fit them with the included Schrader valves and top them up as and when, the controllers are handy if you're loading/unloading a lot, and in fact they're handy at the start when you're playing with pressures to find the right balance but certainly not a necessity as you can just check the bags when you check your tyres, that kind of thing.

The pressures on these go up to 25PSI but I think anywhere between 8-15 is about normal, the gauges on the load support controllers go to 100PSI but that's because they work with a variety of different bags.

With regard to mounting if you were to go for an onboard controller, I'd personally try and fit the compressor in the boot or under the bonnet. They're reasonably splash proof so long as they're not getting completely soaked, you'll probably want to fit it fairly far from earshot although the compressor doesn't run for long on these bags so it's probably not an issue.
I know it has been a while since your post but I was hoping to get some clarification on what is available today for a Caravelle. I have Sachs HD shocks/OE springs and the rear 26mm sway bar and I am happy with this when not towing. I am however concerned about towing a 2 axle food truck and I am thinking to use some sort of an air suspension that I can inflate when towing or carrying heavy weight in the back.
Are the red bags replaced by blue ones now? Are these a good idea for my setup?
Thanks.
 
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