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Notice dude in the first pic still has a tiny bit of shaft showing( safety margin) also keep in mind limit straps stretch on average 1 inch in length per 12 inches of strap length. Back to that safety margin keep it in mind for the droop position also. Doubled straps may be necissary,( less stretch). Straps also gain a stretch memory over time( they stay stretched out) so u can start with a 10 inch strap and it can turn into an 11 in a year.

Shocks mounted on top of leaf spring plates are about 2 inches, give or take higher that they lower oem shock mount location..

In that Scenario a 18 could be utilized..
This pictures shows a 18" 2.5 fox shocks mounted on the spring plate on a stock leaf spring.

1. Take all but your main leaf out make a spacer to take the place of the other springs and bolt up your rear end.
2. bolt your shock onto the lower mount, compress your shocks with .5" left of shaft, cycle rear to full bump.
3. put a piece of card board where you are going to build your upper mount, swing the shock forward and backward with a pen through the hiem, making a arch on the card board.
4. Cycle the rear to full droop, extend your shock minus .5"
5. Again on the card board, swing the shock forward and backward with a pen through the hiem, making a arch on the card board.

Where the to arches intersect will be your ideal mounting point, utilizing all of the shocks travel. If you need to, error on the side of leaning it farther forward.

I've been able to use wood for the "spacer for the leafs on the crew both front & rear. Just a bit of cutting or sanding to get the size correct.

Here's pics of front & rear




Pics of the cardboard thing he talks about. I used wood & bolted to the frame though & left bolted there to start tacking the shock mounts.

I used a chunk of wood on mine as well, no need to over engineer a temp spacer

Everything on this explorer was built in the last few months. All hand built by Andrew Timm at TRAC Performance in El Cajon, Ca.

The rear end cycles 26" of clean travel. From ride height about 10" of bump travel and 16" of droop. All with a 2.5x12 fox coil over and a 3.0x16 fox triple bypass.

So I was at the HDRA Reno race earlier this year and came across an Silver F-150 Prerunner w/ leafs. I spotted something I haven't seen before on leaf spring hangers, not sure what the purpose was for. 1st thought some kind of integrated sway bar? But it had one already. 2nd was, some kind of internal helper spring?? Was hoping someone could share what they know/think this is??, forgot I had the pics and just came across recently.

Cactus Cooler wrote:So I was at the HDRA Reno race earlier this year and came across an Silver F-150 Prerunner w/ leafs. I spotted something I haven't seen before on leaf spring hangers, not sure what the purpose was for. 1st thought some kind of integrated sway bar? But it had one already. 2nd was, some kind of internal helper spring?? Was hoping someone could share what they know/think this is??, forgot I had the pics and just came across recently.

I had an idea I have wanted to try to use a spindle and bearings for shackle pivots. Perhaps that is what this is. I was going to use a small car unitized hub to make it easier than that though.

The shackle is just on a different type of pivot. When your shackles get too long they allow a lot of lateral deflection which creates high speed instability. If the shackle is mounted to a unit bearing or spindle there is no side to side movement. This is why you see panhard bars on front axles with a lot of spring arch or long shackles.

philofab wrote:The shackle is just on a different type of pivot. When your shackles get too long they allow a lot of lateral deflection which creates high speed instability. If the shackle is mounted to a unit bearing or spindle there is no side to side movement. This is why you see panhard bars on front axles with a lot of spring arch or long shackles.

On my 64 kit the shackle hit the hanger quite a bit I was gonna do delrin bushings to tighten it up but this seams like another option.

I switched to Derlin on my shackles as the upper bolt head was rubbing on the mount. Problem fixed.

Oh the idea is now eating my mind. I have found all the part I need now I just need to spend $$ and get to work.

cs_drums wrote:Oh the idea is now eating my mind. I have found all the part I need now I just need to spend $$ and get to work.

To switch to Derlin? Just switch the bushings out.

Kel Fab Creations wrote: To switch to Derlin? Just switch the bushings out.

Nope spindle mounted shackle

I see.

This may have been covered before, but question:
Pitfalls of spring under vs spring over? Is axel wrap the same in both configs?

I've heard spring under will produce less axle wrap. Kinda hard to tell but I didn't notice any when I took that footage of my rear suspension.

A guy I know told me there's more under and I'm having a hard time wrapping my head around as to why.

Spring under:

1. Gravity helps stop axle wrap.
2. Allows lower ride height with more spring arch.
3. Different geometry due to front pivot being higher. (changes anti squat & affecting roll understeer/oversteer) (usually worse)
Allows a longer spring (due to more arch)
4. U-bolts hold vehicle weight in tension.
5. Less chance for negative arch in compression.


Spring over:

1. More ground clearance.
2. U bolts do not hold vehicle weight.
3. Different geometry due to front pivot being higher. (changes anti squat & affecting roll understeer/oversteer) (usually better)