rear lift springs versus shackle flip

[argonaut]

What are the pros and cons of doing a shackle flip over using rear lift springs?

I'm planning out a 4" lift on my 72 Blazer. It will be used for street driving and some off road use, no rock crawling. I'll also want to add a tow hitch at some point.
I was planning to put lift springs in the back, but I've read a lot about the rear shackle flips on here and am wondering what the reasons are that everyone loves them so much.

 

[Yukon Jack]

The shackle flip will push the axle forward a bit - definitely noticeable if that matters to you and of course that can cause the tire getting to close to the front of the rear wheel well.

I've got a flip on my 69 K20 and haven't noticed any effect when towing with it. I went with a flatbed so the axle moving forward didn't matter to me.

On a Blazer I'd swing for the rear springs. If you do the flip, plan on using a set of Off Road Design Zero Rates or something similar to get the axle back more to where it should be.

 

[70jimmy]

If I had stock springs (Old), I would swing for new springs to get the ride you want. just flipping with old worn out springs might not work well, especially with the normal but sag you get with our rigs. The new front springs will have more arch and be stiffer than the longer rear springs. I started with new springs and a flip with one inch more lift in back than in front 4 inch flip back with 3 inch spring and 6 inch front spring and due to sag I have added a zero rate, and longer super shackles, but I do have heavy bumpers and a 37" tire on a carrier and full cage and sliders.

 

[4X4HIGH]

A lift spring will bring a harsher ride over doing a shackle flip where the ride quality remains unchanged. Yes the axle will move forward about 1" when doing a shackle flip so you can either install a set of zero rates or drill a new center hole in the perch 1" forward of the existing one so you san move the axle back to original location (or close to it). If you go this route you must also drill a hole in the top spring plate as well for the center pin to clear.

 

[NV_K5]

My shackle flip resulted in body sway. Serious body sway with the top on or fully loaded. I don't tow with it so I have no opinion about that but assume it's uncomfortable.

I prefer the flip over blocks but would have preferred new lift springs if I could have afforded it. Since you don't really wheel it hard and are considering towing, my suggestion is to get new springs from a reputable source.

 

[BILTIT]

I tow with my shackle flip and it works fine, no sway. I did upgrade to the super shackles from ORD instead of using stock shackles as they are pathetically weak.

 

[AJs72K5]

A lift spring will bring a harsher ride over doing a shackle flip where the ride quality remains unchanged. Yes the axle will move forward about 1" when doing a shackle flip so you can either install a set of zero rates or drill a new center hole in the perch 1" forward of the existing one so you san move the axle back to original location (or close to it). If you go this route you must also drill a hole in the top spring plate as well for the center pin to clear.

I'll add a bit to Scott's response. If you don't want to drill a hole in the spring plate, DIY4X and Ruffstuff also make plates that let you relocate the spring pin as well.

 

[bp71k5]

Like Scott said, lift springs are stiffer than stock springs so the ride quality is harsher with lift springs. A shackle flip lets you keep the stock amount of "harshness", but I think ride quality depends a lot on how much weight you have back there. If you have a lot of weight back there, lift springs might not be a bad choice since the weight will tend to balance the stiffness out.

A stock first gen with no hardtop, heavy bumpers, etc. is pretty light in the back and even my stock springs were kinda harsh when the back was empty. I installed a 4" spring lift in front and a 2" spring lift in back along with the rear 4" shackle flip. The truck sits about level with all the junk in the back and sits just a tad higher in the rear when it's empty and topless. I can't tell any difference in the stability after the shackle flip and I do plan to tow with it at some point.

 

[fishinnutt]

I am unsure which shackle to purchase from ORD for my application. I have a 71 K5, I want to end up with 6" of lift. I want to do the shackle flip and zero rates. Any insight as to which shackle length to choose would be appreciated.

 

[bp71k5]

The shackle flip will provide about 4" of lift and a zero rate will provide 1". You would have to get 2" longer shackles to get up to 6", but I'd prefer to just leave out the zero rate and use 2" lift springs instead.

 

[fishinnutt]

What length springs are the hot ticket? Do you stay with the factory length or do you gain some advantage by having a longer leaf spring?

 

[bp71k5]

Longer springs = flex more.

I think 52's are stock? Which ones are better depends on what you want to do with the truck. Someone else will need to comment on that, but im happy with the stock length. I may switch to 56's someday.

 

[argonaut]

I'm assuming that if you switch from 52"s to 56" then you'd have to move the front spring mount fwd 2" and the shackle back 2" to keep the axle centered in the stock location.