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Discussion Starter #1
So, this stems from some of my other posts.

Starting fresh though, 88 Chevy, 3+3, long box. Getting a dually swap, 12v Cummins, likely 22.5s. Also getting setup for a gooseneck with plans for a 30 ft trailer, and bumper pull 20ft trailer. Either way, it's gonna be pulling some serious weight. Daily driver duties, running errands, parts pickup, motors/diffs/etc. Generally a shop truck.

I've been looking at air ride options, and I'm leaning far towards a link setup and bags out back. Likely a parallel 4-link with a Watts link.

I've been staring at the front suspension, which is a 4" lift spring, (with the stock 350v8), and with the cummins is going to sag, and need some more work. I'll have to pull it apart redo the bushings, add at least one more leaf, and a panhard to take the weight.
I'm thinking about radius arms up front, it's an easy swap since I'm looking at a panhard anyways, but if I am to do it, Bags might be a better option than coils purely for the adjustability.

The truck is still used for camping, and familiy activities, exploring(expedition style), and adjustability wouldn't be a bad thing. I know I could use a smaller bag out front than in the back, internal bumps, etc, so what's everyones thoughts?
 

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I think if any one can pull it off it's you. I've enjoyed reading all your posts and give you props for your fab skills and unlimited ideas. I agree on the rear but have my doubts on the front.
I'm sure it could be done but you would have to stay on top of it all the time. Can you imagine a worn bushing inducing death wobble headed down a mountain grade towing your rig & all your gear?:eek:
Maybe keep the leaves but add bags for a combination height/ride control. When a rig is on full air it tends to get a little crazy when the bags unload under braking.
Just my 02 I don't have a big post count but have over 2 million miles riding on the bags!
 

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My take on front with bags would be just as Wagman said braking would get interesting and keeping up bags would get taxing.
Why not do coils (Cost effective) they make a soft cushy ride with reliability and braking control consistant day in/out.

Im slowing giving in to the full linked rear bag idea but I cant do bags up front no way no how for a tow pig, Show truck hell yes.

my .02
 

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No bags in the front!!!!!

The only time bags would be acceptable is in addition to leafs AND an additional anti-wrap leaf.

Air bags are great for a supple ride, but you will suffer with so much axle wrap every time you brake, that the truck will hop all over the place.
 

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Discussion Starter #6
No bags in the front!!!!!

The only time bags would be acceptable is in addition to leafs AND an additional anti-wrap leaf.

Air bags are great for a supple ride, but you will suffer with so much axle wrap every time you brake, that the truck will hop all over the place.
How do you get axle wrap with a link suspension?
 

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Depends on how you set up the suspension. Class 8 tractors are now using air bags in combination with leaf springs.

Coil springs don't provide any anti wrap. You can easily replace a coil spring with a bag if you have enough room.

Prevost and MCI buses use air ride on the front axle too.
 

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How do you get axle wrap with a link suspension?
The leverage against the links will make the axle lift a LOT under braking when going forward and dip a good 3-4" when in reverse. (unles the links come from the front, then the opposite)

Nature of the beast.
 

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The leverage against the links will make the axle lift a LOT under braking when going forward and dip a good 3-4" when in reverse. (unles the links come from the front, then the opposite)

Nature of the beast.
Not if you get the geometry right. Its just like a 4 link rear suspension with anti dive and anti squat. Get the geometry right and there is none.

08+ Fords use coil springs in the front with radius arms. They don't have a problem with diving when braking.
 

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Discussion Starter #10
The leverage against the links will make the axle lift a LOT under braking when going forward and dip a good 3-4" when in reverse. (unles the links come from the front, then the opposite)

Nature of the beast.
OK. You're talking about anti-squat. That's all about suspension geometry. Has NOTHING to do with bags, which would be the same as coils. So is every coil spring truck unsafe now too?

It is NOT the nature of the beast, and I'd like for you to prove me wrong.

My question was not, should I run links, it was would bags be better than coils.
 

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Coils are progressive in rate, bags are not.

No matter how you tweak it, bags will allow the axle to travel excessively under torque.

Semis have little issue under the rear, due to the torque pushing the axle down. It's a lot of weight, so it just lifts a little.

Put bags under the front, and you have a problem. You only have XX psi of air preventing the torque from wrapping the axle along the radius of the link. It WILL move.

You ever see an empty air ride flatbed in reverse? Watch what happens every time the brakes are depressed. The ass of the trailer lifts to the sky! It's the same thing when you only have 4-5,000 lbs on the front axle of your rig.

Or you could go against my advice and post video of how it works out.
 

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Discussion Starter #12
Coils are progressive in rate, bags are not.

No matter how you tweak it, bags will allow the axle to travel excessively under torque.

Semis have little issue under the rear, due to the torque pushing the axle down. It's a lot of weight, so it just lifts a little.

Put bags under the front, and you have a problem. You only have XX psi of air preventing the torque from wrapping the axle along the radius of the link. It WILL move.

You ever see an empty air ride flatbed in reverse? Watch what happens every time the brakes are depressed. The ass of the trailer lifts to the sky! It's the same thing when you only have 4-5,000 lbs on the front axle of your rig.

Or you could go against my advice and post video of how it works out.
Not all coils are progressive in rate, so you've lost me there allready.

And the rear end issues you're talking about are still an issue with link DESIGN, not air ride. Average heavy duty truck has essentially a radius arm suspension which are notoriously bad for what you are describing.

You have yet to show me ANYTHING that is not design related. Stick that same rear end that you say "lifts to the sky" on a non-pregressive, or even a progressive rate coil, and run your "test" again.
 

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Discussion Starter #14
How about this:

Design a 4-corner air ride without these issues, market it and make a killing!

It hasn't been done to date for a reason.

And they are?

You're missing the point here. You still haven't said why BAGS are no good. You've even said they lift in the rear. Millions of trucks on the road on bags, and you're blaming bad suspension geometry on air bags.

Please. Tell me why BAGS are a bad idea.
 

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Discussion Starter #17
Been there. That's what started all my research months ago, I have a post around about their shackle hanger replacement.
 

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there is a guy in the chevy forum that has and S10 that he has a diesel motor in and all four corners are bagged. check out his build. its definately possible. I think he even tows gooseneck dump trailer with it as well. the thread is called duramax swap in S10 (something like that.)
 

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Discussion Starter #19
I've read that too, It's a whole differant world from my 3+3 dually though.
 

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And they are?

You're missing the point here. You still haven't said why BAGS are no good. You've even said they lift in the rear. Millions of trucks on the road on bags, and you're blaming bad suspension geometry on air bags.

Please. Tell me why BAGS are a bad idea.
- Very little internal friction meaning that 100% of all damping energy absorption has to be handled by your shocks. Meh, not really a big deal.

- You are going to have 10+ wear points (bushings) in the front end that are going to get pounded to shit by the 6BT. If you don't run in salt and you don't care about working on the front end often it may be a non-issue for you.

- They ride like shit. Every bagged car and truck I have ever ridden in (including range rovers with OEM air suspension) rode hard. Its not a spring rate issue, it's almost like they react differently to a shock load than a conventional spring. I think it's because of the non-linear energy absorption of airbags versus coils. By replacing bags with coils on the Rovers you significantly improve the ride. Yeah it's anecdotal but I've seen over 10 different vehicles with air and they all exhibited the same symptoms.

- It's going to be a fairy princess that's going to have air leaks, pain in the ass bushings, it's going to bleed down overnight and blow air lines and compressors and hiss and fuss and be a PITA. And you are going to wish you stuck with bulletproof leaf springs. My opinion, prove me wrong :D
 
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