Military-Wrap Leaf Spring Performance & Testing

[Nd4SpdSe]

Well after some mileage and some use, I finally got some use and pics of my leaf springs under various conditions to post up some results on their performance if anyone was interested in doing the same.

For a while when I first seem them in use on military vehicles, I became curious these leaf springs which are known as "military-wrap" leaf springs, which is to have 2 primary leafs. In researching their application, I found no reference of them being used on an Xterra, and even then, limited info even in Jeep forums but did find out they did some stock on some older Toyotas, but in the end, I was mostly on my own. What I had in mind on how they would function would be:

- Better load handling and should compensate for the removal of the overload leaf, which was removed to allow for better flex, especially with the combination of the Revolver shackles.
- Redundancy if a leaf breaks, would facilitate to be able to limp off the trail and go home for repairs.
- Stiffer ride
- Less sag over time.
- And of course, provide some rear lift.

The rear part around shackle with the wrap looped around the original primary leaf. The secondary leafs were replaced since one was found to be broken as we dd the lift.


Pic of the truck with my lift installed. SLR UCA's can allow the front to be cranked a 0.5-1" more which should level the truck out, but she may stay like that for now since I have heard it's better to have the rear up a tad more than the front.



The front section can't have a loop because of the design of the truck, so it's made with just a hanger. Since it's not fixed in a loop around around the main leaf, it's probably the reason why it has more flex and isn't as stiff as I had suspected it was going to be since it gets to move and slide rather than force tension against the main leaf. If it's possible to design the military wrap to sit on top of the original main leaf rather than under I think you can get her to loop on both sides, but I think you'll get less support in the situation of redundancy if the main leaf breaks; the shackle/mounting bolt will want to slide through the gap in the loop from the weight of the truck.
(pic to follow)

One of the interesting side effects for the setup was that my leaf pack is considerably thinner with only 3 leafs total and no overload lead. Combining that with the Skidderz, the standard shock length is too long.


Although there are a few ways around this, I went with the (cost more than I was quoted, and expecting) inboard shocks relocation. But with that done (and an extended brake line), the shop was anxious to flex-test my truck on their RTI ramp.
Droop.


And stuffed.


The limiting factory to stuffing the rear at the moment is the offset of the rims (running Pathfinder rims that have the sae offset at the stock Xterra), where the tire is resting against the frame/inner fender well. But with that, flex is rather well and unlike as some has suspected, doesn't seem to be limiting it at all. So the flex part is tested and I'm pleased with the results.

Next will be if I sacrificed the trucks ability to handle being heavily loaded. The change to test it was doing camping, with all my tools (suspecting easily over 200lbs worth in a toolbox and contractors bag), 2 boxes of wood loaded right at the back against the hatch, and food and camping gear for two, along with the RTT, the truck couldn't be more loaded. As my girlfriend posted on Facebook, there wasn't much room to spare.


Must say however all that, that the truck handled that exceptionally well!


At the moment, the one drawback is the softness of the rear, especially on acceleration, which I can't say it IS the leafs. The fab guys who did the inboard shocks say I have axle wrap because of the thin leaf pack and want to do a 3rd link or add a leaf. Also my Rancho RS9000XL's aren't in the best of shape since they probably blew (again) a week after doing my lift because of how compressed they were (before the inboard shocks relocation, which was done to rectify that) and that relocation might be making the shocks less effective.

[Nd4SpdSe]

This section saved for off-road testing, which will probably end up being at AW