Usually when i talk to people about this build, the first thing they say is either "that wont work" or "why"... and genuinely, i'm kinda on board with that and totally understand the sentiment.

I wish i had some cool stories about how no one believed this would work, but i heroically pulled it off anyways... but every time i talked to a peer about it i received nothing but support, and belief in me that i could get it done.

The thing is, there's no real reason to build a rear suspension like this. This truck had a very specific set of variables in a specific order that pretty much required this setup. That being said I'll now be building our personal truck this way after seeing just how good the handling characteristics are (especially on the road), but more on that later.

When this build first started it was supposed to be a simple solid axle swap that kept the rear a more traditional spring under leaf spring setup. We quickly realized his original truck bed was beyond saving and opted to build a flatbed. With the customers design for the flatbed in mind i built a simple rear frame section the exact width of the spring mounts and with enough room for storage for trips. ( and yes those are jumper cables going through the sun roof, the dual battery setup didnt have a negative lead ran forward and would not keep the vehicle running lol).

There was no mention of an exo cage or anything else at the time i built the flatbed so i designed one that was simple and i thought looked cool, although i didn't build it to easily terminate an exo cage main hoop into, which explains the goofy structure acting as a massive C pillar. I had a plan to make some cool looking tube fenders but the customer just wanted 2 straight tubes which are now plated and act as work stations/lunch tables.

Anyways, the big issue with this is the spacing. The main square tube rails of the bed are the exact width of the OEM leaf spring mounts to make it easy to land the mounts to. I designed a cutout in the bed to fit the 3.0 bypass for the original setup which coincidentally did not fit a bypass/coilover combo for the link setup. Couple that with the rear axle being the narrowest 14 bolt variant ever produced lead to some interesting fitment issues.

After mocking up the spring under leaf springs, they of course hung down a ridiculous amount. With the springs this thing had a worse departure angle than a stock jeep, which is a bit rough for a solid axle truck on 40s.

Eventually we decided to link it using 3.0 IBP coilovers i had laying around, but the fitment issues persisted. The bed was never designed for links so the only way to achieve any kind of seperation at the axle side was to run the upper link mounts way up on either side to miss the bed completely. At full bump the upper link mounts sit well above the base of the bed, but this was necessary to achieve the suspension geometry the truck needed.

When mocked up with a panhard bar, any orientation of the bar would cause the tires to smash into the bed on one side or another during travel. I mocked up a triangulated 4 link as well, however with the goal of keeping the stock gas tank in mind there were very few options for frame side upper link mounts. The Anti-squat throughout travel and the pinion angle would not play nice with each other while maintaining enough angle in the upper mounts to hold the axle laterally while also not causing really weird wheelbase changes throughout travel.

As a side note, a great trick i use for setting up parallel link mounts is running a piece of 5/8 all thread between them. My best work is done solo in the shop just cranking stuff out so figuring out how to align things and maintain tolerances without another hand is key. To get the all thread out you just cut it in the middle and you can use coupling nuts to reattach it with some lock nuts for later use.

I'd been thinking about a watts link rear end on a truck for at least a decade now. It was originally patented in the 1700s as a reciprocating device for steam engine pistons and has since been used on a ton of vehicles. Some of the major ones including, cop cars, PT cruisers, land rovers, and the new ford ranger raptor. My goal with the rear end was no more than 22" of travel... i find that high rear travel numbers on rock crawlers are actually a huge detriment overall and have slowly changed my build methodology to limit the front to 14-17" and the rears to 18-24" or so. With that limited rear travel number, some quick drawings revealed i'd be well within the angle limits of a horizontally mounted watts link.

This would solve several problems:

1. It would not limit any up travel because of its short packaging, while still allowing the vertical seperation required to play nicely with the limited options for link mounts at the frame side
2. There would be minimal side to side swing, so the tires/link mount wouldnt contact the bed
3. There would be a fixed roll center that is slightly higher than a panhard would have (this could be good or bad though, you do want some body roll and weight transfer to the outside corner in a turn to create traction to pull you through)
4. Because of the position of the upper link mounts, the frame side watts link mounts could be lowered substantially. This horizontal watts link setup could handle another 4" of droop and about 8" more up travel with the heims i spec'd for it.

This photo above was actually from the day i decided the only fix was the watts link itself.

This truck has been all over Johnson Valley, driven to and from the Rubicon a few times, and spent lots of time in the local desert smashing trails. Currently it's a daily driver, taking kids to and from school and is used to haul Safe's for my friends Safe moving business. The watts link has had exactly 0 issues... the bearings are as tight as day 1, the heims are great, nothing can bind under any situation, and it's probably the last part that will break on the whole truck.

Building this was fun, but unfortunately i lost many tens of thousands of dollars doing this build. I have shifted away from custom fabrication all together to focus on my real passion, performance suspension products.

I've had the opportunity to work with phenomenal builders in the past and have been scouted by several auto manufacturers to work on suspension projects which has been really humbling. This build was fun and challenging, but its nothing compared to what's next. Thanks for following along!