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All The 52" Threads Right Here

If you're not planning on crossover, then you can only move the axle forward so much (and 2" is probably too much).

I'm just starting to wonder what portion of the "scary flexy/wobbly" ride with 52's is from the extreme shackle angle. Anybody with B-52's ever test this theory?

What's wrong with locating the front spring hanger directly under the body mount (with 52s) to move the front axle forward 1" and get a slightly better shackle angle than stock?

People seem to say that 30 degrees from vertical is a good shackle angle and 45 degrees is too far, but I've never seen math to reinforce this. It makes good logical sense that the rig will handle bumps better with some shackle angle since the spring is moving in the same direction the wheel wants to move.

shackle angle is not just about a number. It depends on the arch of your spring. A flat spring can have a whole different angle than one with a good amount of arch. and a harder spring whith alot of arch would need a different angle.
 
So for flex, when the spring is basically flattened the shackle should be up around 40 degrees or so? But for cornering on the road, it seems like you want the shackle near vertical at ride height, to minimize the corner sag. With a 45 degree shackle, every 1/2" the spring lengthens causes that corner to lower another 1/4". This is probably why the factory shackle angle was chosen even though here we usually call it "bad" - body roll is minimized.

I've heard a couple cases of swapping 52s in without changing the shackle angle. Apparently the flex isn't much better. So do we have any examples of changing the shackle angle on 48" springs? I wonder how much we confound the results of the two changes.
 
Here is how I have read on how to determine "optimal" shackle angle. Optimum would be where you get the greatest use of the shackles available movement.

Say the fwd spring eye is your fixed point. We can only locate it in a few places. Measure the length of the main leaf of your spring. Not eye to eye, but the length the spring will be when flat.

Now take that measurement from your fixed point (fwd mount) and determine where the rear eye will be when the spring is at maximum up travel.

From this point you can determine where the shackle will be at its maximum angle during compression and adjust the shackle hangar accordingly to your shackle length.

Now with this method very flat springs will result in a different angle that arched springs, but you will get the maximum amount of use of the shackles range of motion.

With 52's you generally end up with a bit of up travel before the springs get flat and a steep ~40* static angle which results in a lot of down travel available. I imagine if you did this with 48's the same result would occur.

The stock shackle setup (probably for handling) is near vertical which provides a decent amount of up and down travel, but the down is limited by the lack of angle available for the shackle to move forward.

Just my .02:waytogo:
 
Let's also remember that the true stock front shackle is designed for neg arch springs and the shackle moves forward with compression. So when we add lift springs or 52s we are changing how all that was designed to work...
 
So for flex, when the spring is basically flattened the shackle should be up around 40 degrees or so? But for cornering on the road, it seems like you want the shackle near vertical at ride height, to minimize the corner sag. With a 45 degree shackle, every 1/2" the spring lengthens causes that corner to lower another 1/4". This is probably why the factory shackle angle was chosen even though here we usually call it "bad" - body roll is minimized.

I've heard a couple cases of swapping 52s in without changing the shackle angle. Apparently the flex isn't much better. So do we have any examples of changing the shackle angle on 48" springs? I wonder how much we confound the results of the two changes.

my holesaw has evaded me so i still have my stock shackle location for my 52s. i will be moving it in the next week or so. they still flex damn good for the crappy shackle angle.
 
Also just a tip when you redrill for the shackle. Make the hole the larger size to fit the aftermarket DIY or ORD shackle hanger. Much easier to drill it large the first time than try to open it up later on. :waytogo:
 
Also just a tip when you redrill for the shackle. Make the hole the larger size to fit the aftermarket DIY or ORD shackle hanger. Much easier to drill it large the first time than try to open it up later on. :waytogo:

I'm still huffy that you can BUY them now ... I decided early on I wanted a single bolt size across the shackles, but had to build my own. :doah:

-- A

new-spring-hangers-welded-8.JPG
 
So if you want the soft spring rate of 52's for ride quality but don't need immense droop, why not just leave the shackle angle to limit droop? Then you may not need crossover or a long slip driveshaft. Or at least you can get to those later on. If the front spring eye is right under the body mount the axle isn't far from the stock location.
 
So if you want the soft spring rate of 52's for ride quality but don't need immense droop, why not just leave the shackle angle to limit droop? Then you may not need crossover or a long slip driveshaft. Or at least you can get to those later on. If the front spring eye is right under the body mount the axle isn't far from the stock location.

sure you can do that, but its like getting a built motor and putting a 1/2 throttle stop on it :haha:
 
edit: Never mind, all the links are dead....
 
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First and foremost, Jekbrown's 52" swap tech writeup: http://coloradok5.com/52inchspringswap.shtml

Zcarzcars's writeup: http://www.zcarczar.com/spring/install.html

52" Spring Drivelines

Some 52" Flex Pics

Reasons for moving the rear mount

More reasons

2" Lift 52's

Lift height of standard 52's

Crossover and 52's

Using 56's instead of 52's

General info and why 52's aren't for everyone

Number of leaves and lift they give you

Shock solutions for 52's

MTMike's swap thread

Another swap thread by Mike

Mike's spring prep

52" Road manners

Using lift 52's

Pro's and Con's of running overloads

Spring lengths

Another swap thread

Shackle length

Con's of 52's on a DD

Another leaf number thread

52's vs. normal lift springs

brake line length

More ford tower info

More 52" flex pics

52's and swaybars

More 52's vs. 56's

Zcarzcars impressions a year later

More 56's vs. 52's

Why you need to move the spring mounts

That's all I've got for now. There are some threads I didn't include because their validity and importance is trivial. If there's a thread that you know of that should be added, post it up. Hopefully this answers most questions if people bother to read these before the start a new thread that's been answered before.

Oh, and just so this shows up in a search I'm gonna throw some keywords down here. spring swap lift tuff country tough 52 56 52" 56" front 3/4 ton mcdonalds and french fries clearance axle move relocation kit rough search more often jekbrown shocks ford towers 14" travel

Sucks that all those links are dead minus the CK5 article posted first...

The only real thing I've disliked about the new format, sooooo many links posted in threads lead to a Error page.
 
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