Rear airbag mount on trailing arms (not stock location)

[ehjorten]

I feel the need to make some comments...say what you will to me, but moving the bag up on the trailing arm does not allow you to run less pressure. In fact you will have to run more pressure because the effective spring rate at the axle is decreased as you move the bag up the arm. Effective spring rate (Reff) is calculated as such: Reff = SP x (L1/L2)²; where SP = your spring rate at the bag, L1 = the distance from the trailing arm pivot to the bag (spring), and L2 = the distance from the pivot to the axle centerline. So...Spring Rate has to increase as you move the bag closer to the pivot.

Why not use air-bag over shocks like the shockwaves and mount them directly off of the back of the trailing arms? This would allow you to run low spring rates and actually give you a slight mechanical advantage over the axle.

[Slammed67]

I feel the need to make some comments...say what you will to me, but moving the bag up on the trailing arm does not allow you to run less pressure.

Thank you.

[SCOTI]

Originally Posted by ehjorten

I feel the need to make some comments...say what you will to me, but moving the bag up on the trailing arm does not allow you to run less pressure. In fact you will have to run more pressure because the effective spring rate at the axle is decreased as you move the bag up the arm. Effective spring rate (Reff) is calculated as such: Reff = SP x (L1/L2)²; where SP = your spring rate at the bag, L1 = the distance from the trailing arm pivot to the bag (spring), and L2 = the distance from the pivot to the axle centerline. So...Spring Rate has to increase as you move the bag closer to the pivot.

Why not use air-bag over shocks like the shockwaves and mount them directly off of the back of the trailing arms? This would allow you to run low spring rates and actually give you a slight mechanical advantage over the axle.

I think most of the guys that are doing mods like this are all about extreme lift & railing. I don't see any reason for moving them if you're just interested in slight height adjustments for driving down the road.

[DM310]

Yeah, this is just my play toy. I could careless if it rides like ****...... as long as look good driving down the road then I am ok Plus there is no way you are going to lay frame w/ the airbags in the same location as the stock coils. As soon as I start driving it I will let you guys know how it rides

[1low1967]

Cantlever suspensions ride very nice better than over the axle, Also running big wheels, lift is needed, True it adds more stress to the arms but if you brace it correctly there is no problem. Shock waves are nice but i heard that they get less lift than firestones(about 7). Its really up to the person and what they are looking for. Air over coil suspension is 100 percent better. Theres so many different variations of rear systems and what you're looking to do. When I did mine i wanted both a nice ride and lift. I have a longbed and in pennsylvania the roads SUCK. Getting extra lift in the back is good for me and my roll pan, plus its a coolness factor to take the plate from sitting on the ground to almost 26in in the air. As for bags Im running Slam specialties. I like them, little more but well worth it. Well thats my two cents, And my opinion...So its really up to the owner.

[smokekiki]

I have a longbed and in pennsylvania the roads SUCK

What?You can't be talking about my area of Pa. I need to take the long way around to get to the grocery store,that is 2 miles away,because the road is so bad ,I bottom out in 2 spots if I try to go the speed limit.

[1low1967]

I'm glad i'm not the only one. Even pulling in and out of some places

[FirstGen]

You just reminded me how much I love Texas...

[jeffnstef]

Originally Posted by DM310

Yeah, this is just my play toy. I could careless if it rides like ****

That's retarded ! If you are looking for something that looks cool put you money into art, not build something that is potentially dangerous to others.

[DM310]

Tell me how the hell what I am building is dangerous. I have posted many pics along the build process and no one has said anything about it not being safe. I am not just some jackass w/ a welder here. I was being a smart ass when I made that commit. What have you built?

[SCOTI]

Originally Posted by jeffnstef

That's retarded ! If you are looking for something that looks cool put you money into art, not build something that is potentially dangerous to others.

Different strokes for different folks.

[cojnit]

some people consider this art!

I know I can't "paint" and "sculpt" like any of these guys!

[sharkskinman]

Bump on old thread!!

I'm figuring on taking the springs off and lowering it as far so that the axle(no current c notch) hits the frame
Then I'm going to slide the bags with mounts attached and compressed to the furthest location forward they will fit..
Concept is that with minimal psi it should bring the truck up to an Ok ride height and have a little travel either way

Gussets are good things to have in an off the frame/arm mount
In fact u can also add 1 each side as if a roof over the bag welded to the edge of the top n bottom of the frame and/or arms

[sharkskinman]

And I'm going to run ss7s in the front with hopefully cupped arms
Ss8 in the rear up from the coil spring spot
I have a stepside so I'll put a mild c notch in it eventually

Maybe dual 3gal tanks under the cab or where ever outside of the bed I can fit them
York on board
Hard line copper n Manual ball valves under the radio

[PGSigns]

It will set on the frame rails with a bag in the stock location. I will actually set up into a 2" notch and rest on the bed floor with the bags in the stock location. Every inch you move it forward will increase the amount of air needed as you loose mechanical advantage.
Jimmy

[SCOTI]

Originally Posted by PGSigns

It will set on the frame rails with a bag in the stock location. I will actually set up into a 2" notch and rest on the bed floor with the bags in the stock location. Every inch you move it forward will increase the amount of air needed as you loose mechanical advantage.
Jimmy

And..... There is no need to run the larger bags in the rear vs the front.

[sharkskinman]

maybe put the 8s in the front