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TnA Rear Axle, Front Adjustable Spring Hanger

CFMi

CFMi

CFM Industries Inc
Vendor
Joined
Oct 23, 2011
Posts
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Location
Frederick, CO
Hey guys!
I was just designing these front spring hangers for the rear axle of our trucks and thought I'd post up my progress. I wanted to make them adjustable (like my rear shackle flips) and have been thinking about them for a while now, just never got around to them. The first hole is in approximately the factory location (within an 1/8" or so), and then there are holes at 1" intervals all the way back to 6" forward of factory. That should allow you to bolt in up to a 64" spring and keep the rear axle centered in the wheel well. Of course you could also move the axle rear-ward if using longer springs by using one of the other mounting holes somewhere in-between (up to 6" with 64" springs).

Here's a pic of the CAD design:

K5_RearAxle_AdjFrontSpringHanger.jpg



-Darren
 
These are perfect for my truck, sign me up for a set. We had talked about this previously, I'm glad you got something now. :thumb:

Are they built to the factory specifications as far as height?
 
Babaganoosh said:
These are perfect for my truck, sign me up for a set. We had talked about this previously, I'm glad you got something now. :thumb:

Are they built to the factory specifications as far as height?
Click to expand...

The first hole is at factory height, yes. But the rest of the holes go forward from there, parallel to the body line - so if you have moved your factory spring hanger forward AND down the angle of the frame, then this will lower your rear ride height a bit. There are two reasons why I did it this way: 1. It will keep the front spring eye from hanging so much lower than the frame rail and getting caught on all those rocks (when moved forward and down at least). 2. If you install this, say with 64's in the forward-most hole, and then want to extend your wheelbase by moving your springs back a hole or two, your ride height will remain the same.

I could always make a different one of these that follows the angled frame so that spring position would be similar to moving the factory mount forward and down, if there is a large enough call for them - but in that case it would seem that you might just as well move the factory mount and be done with it. I'm open to feedback on that though, let me know your thoughts!!

-Darren
 
For my application on a lwb truck the gas tank is right next to the hangers. Would I still be able to put in a set of 64's and keep the axle centered?
 
swap to a short bed 16gal tank and maybe it will clear .

pics of 64 swap I did years ago on a long bed.

you can see old holes of stock positions . and note no real weight in truck just rolling body at this point . and stock 1ton 5 leaf rear springs brand new .

big truck 001.jpg


big truck 003.jpg
 
Well, I just realized that I designed these off of an early model frame that has the 4 rivets on the side of the frame and 4 more rivets under the bottom of the frame since that is what is sitting in my bay right now. My shop Jimmy and probably what most of you will have is the style that has 6 rivets on the side of the frame and nothing underneath.
Since my Jimmy is not street legal right now, and it's an hour from the shop, it's not real easy for me to pull a spring hanger off to measure the holes in the frame.

SOOOO - does anyone want to pull real accurate measurements off their frame for me? I'd rather get measurements from the old holes in the frame after the factory spring hanger is removed since that will be easier to measure and more accurate. The next best way to measure would be to measure the rivets on a still-installed factory hanger. A removed hanger is not an option since they "spring" a little bit once removed. OR - does anyone have a drawing of the pattern?


-Darren
 
woow sorry :eek1:

my pics are early 77 k30 1ton frame before gm used 4wd hangers with lower support bracket .

my pics are for position refrence only . :popcorn:
 
sweetk30 said:
woow sorry :eek1:

my pics are early 77 k30 1ton frame before gm used 4wd hangers with lower support bracket .

my pics are for position refrence only . :popcorn:
Click to expand...

No worries man, it seems GM used both types of hangers throughout the years. I'm not sure which ones they used when and why though. The 8-rivet (4 side and 4 under) set that I designed off of were on a 1974 4wd Blazer frame. The set that is on my 1987 4wd Jimmy matches the ones you have in your pics of the 77 K30. I guess I'll just have to make both styles depending on what the customer has.

Here are mine on the '87 K5 Jimmy:

20140901_172216.jpg



-Darren
 
you prob know the 1ton truck stuff is different then 1/2 and 3/4 ton for the narrower spring spacing .

just makin sure I know it and even goofed 1 time :doah:
 
sweetk30 said:
you prob know the 1ton truck stuff is different then 1/2 and 3/4 ton for the narrower spring spacing .

just makin sure I know it and even goofed 1 time :doah:
Click to expand...


Yep, the spring spacing is slightly different on the K30's at the shackle flip for sure - I'd assume the front spring hanger is different too, but I haven't measured them and compared them side by side so I'm not totally sure on that. I've seen many vehicles with angled springs (wider at the front than the rear usually) so I wouldn't be overly surprised if the fronts were the same between the 1-tons and the lighter vehicles.


Anyways, I stayed really late at the shop tonight, measured for the third and fourth times, tweaked a few things slightly, then went at these with the Plasma table. Here is the first one tacked together but not fully welded yet:
20140903_193227_1.jpg




20140903_193208.jpg



-Darren
 
That is fine, no rush on my end. Not like my build is going to be done anytime soon.
 
Babaganoosh said:
Ttt any update? Sorry I'm just excited for these.
Click to expand...

The only update that I have currently is that the first set of the 8-bolt style has shipped out and will hopefully be installed soon for testing. The 6-bolt style still needs to be designed, it's coming but my time has been severely limited in the last few weeks. I think it will be another week before things slow down a pinch so I can get on the other design.

I'm glad to hear you are excited for these - it means alot to me to hear that people are liking my stuff and reassures me that I'm designing the right parts :)
 
Once I get some cash consider me the first purchaser.:thumb:

Can you clear this up for me? I'm having a hard time grasping it. With these in the stock position you can put a set of 64's and have the wheels centered in the wheel well? How does that work?
 
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