C notch or Step notch

[roofingbloke]

I have a 63 long fleet,

I will be using air bags between the chassis and controll arms & 2" lowering blocks, also running 20" x 10" with 40 profile tyres,

So i am not sure if to go with a c notch and a step notch,

Any ideas guys,

[N2TRUX]

All you need is a C notch. You stock arms will limit how low you can go.
Posted via Mobile Device

[roofingbloke]

? what if the air bags were in a different place,

[N2TRUX]

Unless you change/modify your rear suspension system, your stock arms are still the limiting factor regardless of where your bags are mounted.

[lolife99]

Originally Posted by roofingbloke

? what if the air bags were in a different place,

In theory,... you could go 3" lower.
(the compressed height of most 2600 convoluted air bags is 3")

This would require you to use a smaller step notch.

[roofingbloke]

Originally Posted by lolife99

In theory,... you could go 3" lower.
(the compressed height of most 2600 convoluted air bags is 3")

This would require you to use a smaller step notch.

Thanks lolife99, I think thats the other option i was thinking about,

I dont want to do a c notch and then rip it out for a step notch, Better get under the truck with my tape measure,

Thanks guys for your help. any pics of alternative bag positions ?

[nastyc10]

Go with a small step notch. You will probably want to go lower than what a c-notch will get you. No use in doing it all over when your not happy with it. I've been there. You may have to trim the inside bottom of the frame because the trailing arm may hit it when you air down.
I would also make sure this is all you really want. It sucks to do it all and then wish you would have put in a bigger notch so you could go lower.

[SCOTI]

Originally Posted by nastyc10

Go with a small step notch. You will probably want to go lower than what a c-notch will get you. No use in doing it all over when your not happy with it. I've been there. You may have to trim the inside bottom of the frame because the trailing arm may hit it when you air down.
I would also make sure this is all you really want. It sucks to do it all and then wish you would have put in a bigger notch so you could go lower.

A smaller step notch will likely be stronger vs. a c-notch that removes 60% of the frame material directly above the notch area. That frame height is where the strength (or weakness) is.

[kev2809]

well, i have 2" blocks with bags in place in of coil and the axle goes all the way up through the frame, so a small c notch but would be holding me up a few inches at least. i went with a huge step notch lol...but better safe than sorry. i hate redoing things. i do want to add though that the bags are hammered flat when its aired out. im not sure if they are designed to be that smashed flat...maybe someone will chime in.

[SCOTI]

Originally Posted by kev2809

well, i have 2" blocks with bags in place in of coil and the axle goes all the way up through the frame, so a small c notch but would be holding me up a few inches at least. i went with a huge step notch lol...but better safe than sorry. i hate redoing things. i do want to add though that the bags are hammered flat when its aired out. im not sure if they are designed to be that smashed flat...maybe someone will chime in.

Depends on the bag. Some have internal bump-stops, some dont.

[kev2809]

dominators...im not sure if they do..

i know the slams do though

[roofingbloke]

I am know looking at different air bag locations, looks like i will be going for a Porterbuilt step notch,

Any pics anyone,

I have just been looking at the porterbuilt web sit and i am not sure of the difference between the tubular/adjustable trailing arm x member and the carrier bearing x member,

[PBFAB.COM]

Originally Posted by roofingbloke

I am know looking at different air bag locations, looks like i will be going for a Porterbuilt step notch,

Any pics anyone,

I have just been looking at the porterbuilt web sit and i am not sure of the difference between the tubular/adjustable trailing arm x member and the carrier bearing x member,

We have a couple different variations of the Adjustable Trailing Arm X-member:

One to be used with a one-piece drive-shaft; and another for a two-piece drive-shaft. The version specific to the two-piece driveshaft has a mounting pad for the carrier bearing.

The carrier bearing crossmember does not have mounting pads for the trailing arms.

One Piece Version:


Two-piece Version:


Carrier Bearing X-member:

[hotrodhomi]

Originally Posted by porterbuilt

We have a couple different variations of the Adjustable Trailing Arm X-member:

One to be used with a one-piece drive-shaft; and another for a two-piece drive-shaft. The version specific to the two-piece driveshaft has a mounting pad for the carrier bearing.

The carrier bearing crossmember does not have mounting pads for the trailing arms.

how much lower will that make the rear compared to the stock cross- member? Also, is there anything else that needs to be changed if the x-member was swapped besides the bigger notch?

[PBFAB.COM]

Originally Posted by hotrodhomi

how much lower will that make the rear compared to the stock cross- member? Also, is there anything else that needs to be changed if the x-member was swapped besides the bigger notch?

Neither crossmember will lower the truck just by bolting it in place. But what it does is give adjustability to the fore-aft location and also the height of the front mounting points.

The advantage to this is being able to move the axle rearward, centering it in the aheel well opening. The adjustable mounting points for the front pivot of the trailing arms allows you to move the front pivot point higher, changing the instant center of the rear suspension.

The two-piece drive-shaft version does give more clearance as its lowest point is higher than the bottom of the frame-rails.

In order to actually lower the truck, a notch will be necessary. This trailing arm crossmember just allows some tuning ability to a lowered rear suspension.

[PBFAB.COM]

Other mods may or may not be necessary depending on how low you want to get.