Author Topic: Do I have 52" or 56" rear leaf springs?  (Read 17128 times)

Offline scout75

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  • 1974 K20
Do I have 52" or 56" rear leaf springs?
« on: May 22, 2016, 08:38:42 pm »
My question is do I have 52" or the 56" rear leaf springs on my truck. I have a 1974 k20 and the gvwr is 8200 pounds total. 3500 pounds for the front and 5500 pounds for the rear. I don't know if the weight rating is helpful or not but I thought I would include it anyway. I am asking because I want to get heavier duty leaf springs for my tuck and the options are 52" or 56". I also understand that I can't just measure from one bolt hole to another and trust that reading. If anybody has some reliable information on how to determine this measurement I would appreciate it.

Offline scout75

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  • 1974 K20
Re: Do I have 52" or 56" rear leaf springs?
« Reply #1 on: May 23, 2016, 08:48:11 am »
I called a leaf spring company this morning and they told me to measure the curvature of the rear leaf spring from the center bolt to the rear shackle.  the distance on the front half of the rear shackle is 26" for both the 52" and 56" setup.  The rear half of the measurement will be 26" for the 52" spring or 30" for the 56" spring.  If anybody know different please respond but i think this is the correct and easiest way to measure the rear leaf spring to determine which size someone might have.

Offline Rattler12

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Re: Do I have 52" or 56" rear leaf springs?
« Reply #2 on: May 23, 2016, 09:48:15 am »
Take your current springs to a spring shop and have them add a leaf ......or two. Why do you want more spring? 
83 C-10 shorty 454, 5spd, 3:73 posi

Offline LTZ C20

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Re: Do I have 52" or 56" rear leaf springs?
« Reply #3 on: May 23, 2016, 12:00:24 pm »
What you said the spring shop told you is correct. This is how you measure a spring.



If you take a tape measure and go directly from A to B. It should still be either 52 or 56 inches. I measured mine as the picture indicated and got 56, then I went from A straight to B and still got 56.

You said your truck is a 74 K20, my truck is a 73 C20, but my friends truck is a 75 K20, his rear springs are 52 inches, so yours should be 52 also. I believe being a 4x4 makes it 52 inches and a 4x2 makes it 56 inches.
LTZ Cheyenne C20