Quad Airbag suggestions?

This is an interesting thread. My bags are original and still working ok.. But I have doubts on their remaining useful life. When I inflate from being fully drooped, like if I leveled for a campsite, my left side takes lots longer to raise. My bags have some weather checking also. They maintain pressure pretty well... It will take a month or more to leak down.

So... Do I replace pre-emptively and with what? Do I maybe have a compressor problem instead? Had anyone tried the cinnabar replacements?
 
Just wondering whether anyone is using the OEM style airbags that Cinnabar has had made. I need new airbags and am tossing up between the Applied mono bag system and the Cinnabar OEM.

I hear that the quality was off at the beginning but has improved. Can anyone confirm?
 
Mike_H said:
This is an interesting thread. My bags are original and still working ok.. But I have doubts on their remaining useful life. When I inflate from being fully drooped, like if I leveled for a campsite, my left side takes lots longer to raise. My bags have some weather checking also. They maintain pressure pretty well... It will take a month or more to leak down.

So... Do I replace pre-emptively and with what? Do I maybe have a compressor problem instead? Had anyone tried the cinnabar replacements?
Click to expand...
gerryg said:
Just wondering whether anyone is using the OEM style airbags that Cinnabar has had made. I need new airbags and am tossing up between the Applied mono bag system and the Cinnabar OEM.

I hear that the quality was off at the beginning but has improved. Can anyone confirm?
Click to expand...
Everything I have heard (all second hand) is the quality / longevity is not there on the aftermarket non-Firestone bags. That i why others like Sully and Alex F. came up with better alternatives.

There were a couple of others too but they did not work out and had to be quietly recalled.
 
  • Like
Reactions: Mike_H
Ken B said:
Everything I have heard (all second hand) is the quality / longevity is not there on the aftermarket non-Firestone bags. That i why others like Sully and Alex F. came up with better alternatives.

There were a couple of others too but they did not work out and had to be quietly recalled.
Click to expand...
Thanks Ken. I’m considering the Applied mono bag setup at the moment. I think they are very much like the sully bag.

www.gmcrvparts.com

MONO BAGS KIT - GMC MOTORHOME

We are a major supplier of GMC Motor Home, RV Parts. Serving GMC MOTORHOME owners everywhere.
www.gmcrvparts.com

Heard anything about this one?
 
I bought a mono bag system from Applied a few years ago. One side became deflated and then it would not accept air to bring the coach back up. Turns out that internally, the bag collapses over the fill hole so the air cannot enter the bag. I had to get a floor jack to slightly raise the bogie. Then the airbag would inflate.

To this day I am conscience about not lowering the airbags too much and causing this to happen again.

Moral of the story, be sure the air bags have internal bump-stops to prevent this from happening!
 
RF_Burns said:
I bought a mono bag system from Applied a few years ago. One side became deflated and then it would not accept air to bring the coach back up. Turns out that internally, the bag collapses over the fill hole so the air cannot enter the bag. I had to get a floor jack to slightly raise the bogie. Then the airbag would inflate.

To this day I am conscience about not lowering the airbags too much and causing this to happen again.

Moral of the story, be sure the air bags have internal bump-stops to prevent this from happening!
Click to expand...
Thanks RF. When I made my first enquiry Nick did tell me that the bags had a bump stop in them but I didn’t realise the significance of this. I’ll be sure to confirm the bump stops are there.
Are you happy otherwise?
 
gerryg said:
Thanks RF. When I made my first enquiry Nick did tell me that the bags had a bump stop in them but I didn’t realise the significance of this. I’ll be sure to confirm the bump stops are there.
Are you happy otherwise?
Click to expand...
They don't have the range of travel and with a cone on one end only, the ride seems firmer.

I heard Cinnabar had some quality issues with the first batch of Firestone reproductions. But I haven't heard any issues since. I'd like to goto back to the double cone OEM style.
 
RF_Burns said:
They don't have the range of travel and with a cone on one end only, the ride seems firmer.

I heard Cinnabar had some quality issues with the first batch of Firestone reproductions. But I haven't heard any issues since. I'd like to goto back to the double cone OEM style.
Click to expand...
The Cinnabar option would be considerably cheaper for me too. I wouldn’t need to ship a bunch of metal plates.
Do you know anyone that has the repro OEMs? I know that YouTube fellow, ‘Andrew’s GMC’ has them.
 
gerryg said:
The Cinnabar option would be considerably cheaper for me too. I wouldn’t need to ship a bunch of metal plates.
Do you know anyone that has the repro OEMs? I know that YouTube fellow, ‘Andrew’s GMC’ has them.
Click to expand...
Hi gerry i have put on the sully bags (which is a load sharing system) I shipped the bags from the states and had the plates made here . I have a set of plans if you want .

The Sully bags are rated for over 4000lbs whereas i cannot find any specs etc for the Fererra Bags and I suspect them to be a smaller load rating

I also found this on the QLD government website, this would sway me to stay with a single bag system.
You need to scroll down to the bottom of the page regarding loadsharing

https://www.tmr.qld.gov.au/business...-sheets/Measuring-motor-vehicles-and-trailers

1701733931072.webp
 
  • Like
Reactions: Kendra and Christo
Cadelec said:
Hi gerry i have put on the sully bags (which is a load sharing system) I shipped the bags from the states and had the plates made here . I have a set of plans if you want .

The Sully bags are rated for over 4000lbs whereas i cannot find any specs etc for the Fererra Bags and I suspect them to be a smaller load rating

I also found this on the QLD government website, this would sway me to stay with a single bag system.
You need to scroll down to the bottom of the page regarding loadsharing

https://www.tmr.qld.gov.au/business...-sheets/Measuring-motor-vehicles-and-trailers

View attachment 9866
Click to expand...
Thanks Trevor. I’ve decided to stick with the OEM style for the moment. Shipping metal from the USA is crazy expensive at the moment.
 
gerryg said:
Thanks Trevor. I’ve decided to stick with the OEM style for the moment. Shipping metal from the USA is crazy expensive at the moment.
Click to expand...
I was going to stick with the original designed airbags. However, when I tried to purchase from Applied this summer they were listed as NO STOCK. I called to find out if they were expecting more anytime soon.
I was told that they were having many issues with the quality of the bags and decided to pull them from stock and will not put them out to the community. My second choice was the Mono Bag / Sully style bag. I've been happy with them since installed. Good Luck
 
  • Like
Reactions: Cadelec
I've decided to replace my early Harrison quad-bag system. If I had OEM I'd leave it that way - but my starting point is an early quad-bag.

Two years ago I hit a large deep pothole at 60mph, lost a bag but was able to drive an additional 1k miles on 3 bags. I replaced all four with same part# Firestones. This week I lost another bag the same way, same location - rough roads in the northwest corner of Nevada, large pothole at 60mph. I isolated the good bag on that side and continued. A few hundred miles later, 2nd bag on same side blew. I continued several hundred miles home with zero PSI on that side. A bit challenging to steer and a rough ride, but I did appreciate not having to jack it up on the side of the road to install bags or a temporary spacer.

Right now I'm strongly considering the SullyBilt system, although I am also looking at the newer quad-bag system (I've heard the geometry improved after the previous owner installed these in 2016). I'm aware the Sully monobag lets each wheel articulate more, wider max/min range (compared to quad), smoother ride, etc. I don't tow anything, and if I do it will be a small light trailer.

I imagine a blown Sully behaves same as OEM - must stop and replace bag on the road, or fit an equivalent block or spacer. If that's the case, is it worth carrying a block of wood (spacer)? Or carry one or two spare bags.

Anyone else with experience removing a quad-bag system and installing Sully? The instructions I've seen assume the starting point is OEM and I need to understand if the previous quad conversion eliminated parts I need.
 
Kendra, I posted 3 replys in this thread. scroll back to May 23, 2021, the second one also on May 23, 2021 and May 24, 2021. Read my experience with original, Sully, and Harrison 4bag. JFYI for you. Maybe will help you with your change.
 
  • Like
Reactions: Kendra
Larry - how bad was the rear-brake lockup with the relatively soft Sully system (and a strong brake system)? Something rare for a panic stop, or quite often while dealing with with typical traffic and road conditions?

I am planning for a reaction-arm upgrade but have found the issues with my quad-bag frustrating (bags should last more than a couple years). I've been running Firestones, so I know bag quality isn't the problem.
 
Kendra said:
Two years ago I hit a large deep pothole at 60mph, lost a bag but was able to drive an additional 1k miles on 3 bags.
Click to expand...
Ouch. 1000 miles on 3 bags? I'm assuming you and yours made it without further problems, but I'm always sketched out by the talk of running on three rear wheels. Figure a ton for each rear wheel, one wheel with no load, 4000 pounds on that side's remaining tire. The common load range E tires and Alcoa wheels both spec a max load of ~2700#

50% over the load rating, in an unbalanced loading condition, for an extended amount of time. A replacement bag wasn't available at the time?
 
Kendra said:
Larry - how bad was the rear-brake lockup with the relatively soft Sully system (and a strong brake system)? Something rare for a panic stop, or quite often while dealing with with typical traffic and road conditions?

I am planning for a reaction-arm upgrade but have found the issues with my quad-bag frustrating (bags should last more than a couple years). I've been running Firestones, so I know bag quality isn't the problem.
Click to expand...
Kendra, I thought it locked up pretty easy. I only made one trip with it and if I had to do a medium hard stop for a stop light change, I could hear the skid, see the smoke in the mirror and the skid mark on the pavement. I spent most of the trip anticipating possible quick stops, always looking ahead. As noted in my other posts, I changed to the Lenzi big brake system, so installing the 4 bag, really tamed the lock-up. IMO, the big brake system with the sully bags is a formula for flat spotting tires on the 3rd axle. Wait and see if you have others who had a like experience.
Also, as I noted, I did not notice a nickels worth of ride difference between the big bag and the 4bag. Also, taking the 4 bag off is a SOB job having to remove the exhaust system in the bogie area to get at the bogie bolts. Doable but not easy. JWIT
 
GMCMI Fall 2026 Rally
Applied GMC

Share this page

Share this page
Top Bottom
Back