I need the area aft of my rear axle for a sub tank on my 80 series land cruiser. I am more than willing to massage the shape of the fenders and even tub the rear fenders a bit but I want to keep the shocks out of the interior. The only place I could have a shock hoop inside anyway would require attaching the bottom of the shock to the axle or close to it reducing travel with a given shock length.
It is not to scale for sure but just the basic concept.
It would allow for a traditional type of lower link and for the mounting of shocks a bit farther forward than a "helmet" link or some of the other cantilever systems I have seen. I also think the two links for the bottom of the shock are a simpler way than a rocker arm.
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The main problem with that is your motion ratio is going the wrong direction. AT full bump your shock would be doing almost nothing. You would be way better off with a bell crank set-up.
It will work but with that design you will find that the shock performance curve is ramping down...
Right at the start of the wheel travel (from bottomed out) the shock will compress at the fastest rate, and the further up the wheel comes the slower the shock compression... just looking at it I'd say the last 4" or so of wheel travel would have next to no shock response
The ride would be harsh on small bumps and it would bottom out aggresivly on large landings
If all you are worried about is locating the shock under the floor of the truck... run fixed pivot pionts off the chassi and a cantilever arm this will make your shock perform the same as dirrectly attacted to the swing arm
you havn't changed the design... the motion on the shock will be exactly the same
I was going to draw a pic to show you the motion and how it effects the shock but I've got a couple of clients in the shop so I'll make this quick
hold your hands out infront of you, so you can look at the sides of your hands, fingertips piont to piont, this is where the shock attatches one palm is the chassi the other the swing arm, now keeping your fingers straight move the shock mount a bit... with your fingers near flat notice how your palms dont get closer but you have alot of movement at your tips, so if that was on your truck the shock & spring would be working ALOT for very little wheel travel
Now peak your fingers this is simulating full travel notice how your palms can move in and out easily with no in and out motion at your finger tips.... so you suspension on the last of its travel would be increadably soft bottoming out very harshly
Have you thought about what chaplain did on his 4runner? you wouldn't have room for a coilover but you wouldn't have to mess with all the complications of a cantilever system. http://www.ttora.com/forum/showthread.php?t=88480
Not enough travel.. 12" of travel can be done on the 80 by modifying the existing shock mounts.. 10" is pretty easy to do.. But in either case you need to lower the bump stops to prevent bottoming the shock out. It works out ok for crawling articulation but reduces whooptybility.
As you can see form that shot that a large shock could fit if it was closer to paralleling the frame rail. I kind of like the challenge and think it is all worth it if I can get a bunch of travel out of it.
This is all just the basic concept. Once I have a direction I will use a CAD program and crunch some numbers.. Does this look more like it?
Can you make that any smaller lol getting better but you need to make your cantilever arm "L" shaped so you shock mounting arm will compress the shock .... at the moment its not really compressing the shock....
Your heading in the right direction with your last design. I would put a little more thought into the design of the bellcrank. I posted some photos of other cantilever designs people have built in the past. Granted most of these are mounted on leaf spring vehicles but the concept is the same. The last photo is the old Baldwin TT. Here's a link to a thread not too long ago which has some good info.
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