Air bag suspension for an OME lifted 100 (1 Viewer)

[Mago]

I've searched the web for air lift suspensions. They don't mention they have different products for lifted vehicles. I figure since the spring coil is longer, the bag should be longer, right?

So are there different versions of the bags for lifted vehicles? Mine is lifted by 2".

Thanks.

s8nlH

 

[dclee]

I run their standard kit in my truck, which is lifted about 1.5 - 2". No problems so far.

 

[Mago]

Does this mean the bag is 1.5-2"" shorter than the coil, and thus will not start working until the truck is already down by 2"?

 

[Campfire]

I'm running the Ailift bags in my 865's and do not have any problems. I just had to drill out the bottom hole in the lower spring mount for the air line to go thru.

 

[Trunk Monkey]

Does this mean the bag is 1.5-2"" shorter than the coil, and thus will not start working until the truck is already down by 2"?

I can't remember how much shorter than the coil the air bags on my friend's 100 are, but they work really good. Their purpose is to take some of the load off the coil spring, so they shouldn't come into play until the spring has compressed a bit anyway.

 

[hoser]

Call the company and tell them what you have. I would think they would be able to cross reference a taller bag with the same diameter.

 

[EdsCruisin]

If you use the Airlift brand and run the supply lines through the bottom spring mounts you could buffer the top mount by cutting off less of the rubber bumpstop, or adding a spacer to it. My first set were Firestone and they came with two nylon spacer disks about 3/4 inch thick. You could create the same effect and bolt it in where the rubber bumpstop is without compromising the suspension.

BTW the Firestones connect through the top spring mount with quick connect fittings that don't hold well. The Airlifts are a simpler, more effective design from the bottom. Just be sure to run the air lines safely past the tail pipe and leave enough slack for axle movement.

 

[re_guderian]

I just recently bought and installed some Firestone's for my 100. I called Firestone and asked for the kit that would fit a 2" lifted truck, and IIRC, it was the 4142? I'd have to look it up... Anyway, I ended up putting the OEM springs with 30mm spacers back in. The extended bags are still shorter than the resting height of the unloaded rig. And BTW, the "Firestone" bags were red, with barbed fittings, and the air line has "Air Lift" printed on it. I was in somwhat of a quandry as how to mount, as the instructions were for the Firestones, but I obviously had Airlift bags. I removed the upper bumper entirely and routed through the top with the spacer on top. I don't like the top routing, and at full droop and 5 PSI while wheeling, the bags will drop down inside the spring. Since the hole in the top is only 8mm and threaded, upon compresssion the hose doesn't freely move through the upper threaded hole. I'm going to flip mine around and route the air hose through the bottom. Don't overthink the height of the bag too much, though I'd call and ask for the longer bag, same diameter. The space between lower and upper spring mount can vary by 9" from full droop to full compression...

 

[dclee]

The thing to keep in mind is that the bag is meant to assist the springs, not act as a replacement. Therefore, it doesn't have to match the free height of the coil, or even the standing empty space when the truck is settled on all four wheels. Even with stock height springs, the bags don't fully take up the space between spring perches. I'm not an expert, but what they appear to do is increase the tension on the coil by adding pressure outward and even between each coil, not upward and downward on each spring perch.

 

[re_guderian]

The thing to keep in mind is that the bag is meant to assist the springs, not act as a replacement. Therefore, it doesn't have to match the free height of the coil, or even the standing empty space when the truck is settled on all four wheels. Even with stock height springs, the bags don't fully take up the space between spring perches. I'm not an expert, but what they appear to do is increase the tension on the coil by adding pressure outward and even between each coil, not upward and downward on each spring perch.

True, but just for grins I did some msmts, and at 35 PSI, they do expand upward several inches. Sure you can use stock ht bags on a lifted truck, it just means your gonna sag a litte more before the bags start "helping". At ride height I have a few inches of empty space between the bag and the mounts.

 

[EdsCruisin]

Even with stock height springs, the bags don't fully take up the space between spring perches. I'm not an expert, but what they appear to do is increase the tension on the coil by adding pressure outward and even between each coil, not upward and downward on each spring perch.

I disagree. When you put air in those bags and apply a vertical load, they contact the top and bottom spring perches. Centrifugal pressure on the coil is not going to counter the direction of the spring action, especially when wet. It does not extend between the coils at all.

 

[dclee]

Like I said, I'm not an expert. Mine seem to "help" with as little as 7-10 PSI in them. But I have a very small lift and my bags actually sit nearer to both spring perches at regular ride height than I originally thought (just took a quick look under the truck as I was out there taking out the garbage).

 

[Mago]

Well after some research I found out that some companies sell air lifts for different lift heights. Standard, 1" and 2". Which proves a point. Even though not critical, I think using spacers diminishes the functionality of the air bag. The 2" lift air bag should be 10" high.

Here's a link:

POLYAIR LC100 with 2" LIFT COILS, REAR ADJUSTABLE AIR BAG KIT - incl. FREE SHIPPING!!!

 

[Mago]

10"

I can confirm after buying the PolyAir Air bags for the 2" lift, it is 10" high, a coupld of inches higher than those for the stock car.

 

[re_guderian]

True, but just for grins I did some msmts, and at 35 PSI, they do expand upward several inches. Sure you can use stock ht bags on a lifted truck, it just means your gonna sag a litte more before the bags start "helping". At ride height I have a few inches of empty space between the bag and the mounts.

and here's why mounting the bags according to the Firestone directions with the air line running through the small (8mm) hole in the top spring perch sucks... At low inflation pressures, the bags will drop during spring droop articulation situations. When they compress again, the line sometimes hangs up in the threaded hole in the top spring perch. Drilling out the bottom spring perch for the required clearance is a much better idea (though some seem to have qualms with it - the hole area being enlarged is not structural to the spring mount and is mild steel). Plus, you can route the passenger side air line along the axle and up the upper control arm on the driver's side to keep it away from the exhaust. BTW, it took me about 15' of line to route it that way, and to the valve which is by the hitch on the bottom side of the rear bumper.

 

[Mago]

PolyAir suggests a 3/4" hole in the top spring cup for the hose to pass through.

 

[Skidoo]

Can confirm it makes a difference to match height of airbag to lift. Ran standard Airlift bags with 866 springs for a year and even with lots of air, while better, it was soft in rear when loaded. Read this thread, found my old bumpstops, cut them down to 2" high and installed them. Wow, what a difference like having new springs.

 

[Mago]

Glad I could be of help..