Front 4 link/coil suspension. Anyone done it ?

[mudguppy]

correct me if I am wrong, but in a leaf sprung suspension ... "pulling" the leaf and the axle back with it, causing the same problem mentioned above. ...

not a 'problem', rather it will ride better than if the shackle were at the rear. the way the OP's springs are set up now is like a 'leading link' system.

... The ideal geometry would walk or push the tire forward as you try to climb, thereby assisting your ascent.

it depends on your objective; if the vehicle is built primarily for offroad obstacle climbing, then yes. but few rigs in this audience are primarily offroad trucks and do indeed spend most of their life on the road. therefore, a leading link system (shackles at rear of spring) would afford a more comfortable ride and handling.

also, right now with the steering arrangement, it could be dangerous to have the spring shackles up front or build a trailing link suspension. the arc of the drag link opposes the arc of the axle in a trailing link design. so unless the steering was changed to a cross-over type, full-hydro, or a complex linkage system utilized.

 

[JCole]

ran across this New Project: M35 6x6/Hino Hybrid (Yes, THAT one.) - The Something Awful Forums

not the way i expected it to be spliced together but it makes sense and was probably a lot easier.

It's heavily reinforced. That area of the frame is stronger than anywhere else.

 

[JCole]

we just finished our new mud truck frame its 4 link with 5 ton military axles.i dont see why a 4 link wouldnt work on your truck.buy good quality hiem joints.we designed all our mounting brackets and had them made on a computerized plazma machine.since we supplied the steel this was pretty cheap .we also used 2x2 1/4 wall thickness tubing for the link bars since shipping and buying dom was real expensive.the front coils are from and f 350 and are huge.good luck on your project

Any pics of the buildup ?

 

[JCole]

not a 'problem', rather it will ride better than if the shackle were at the rear. the way the OP's springs are set up now is like a 'leading link' system.




it depends on your objective; if the vehicle is built primarily for offroad obstacle climbing, then yes. but few rigs in this audience are primarily offroad trucks and do indeed spend most of their life on the road. therefore, a leading link system (shackles at rear of spring) would afford a more comfortable ride and handling.

also, right now with the steering arrangement, it could be dangerous to have the spring shackles up front or build a trailing link suspension. the arc of the drag link opposes the arc of the axle in a trailing link design. so unless the steering was changed to a cross-over type, full-hydro, or a complex linkage system utilized.

thanks for the advice. I would like to do a leading link setup and thought about it, but the way the frame is designed, it tapers down at the front. The cross section is about 4" vertical. Since I will be hanging a large bumper off this area, I don't want to assign it to weight bearing suspension duty also.

 

[mudguppy]

thanks for the advice. I would like to do a leading link setup and thought about it, but the way the frame is designed, it tapers down at the front. The cross section is about 4" vertical. Since I will be hanging a large bumper off this area, I don't want to assign it to weight bearing suspension duty also.

honestly, the easiest thing to do is build on what you already have - your leaf springs are already a leading link design. add a cross member between the spring hangers (or slightly rearward). add a vertical bracket on the axle tube, connect to this bracket via upper control link from the cross member at the spring hanger (or at points on the frame rearward of the spring hangers). not you have a 4-link that will solidly locate the front axle.

i know the leaf springs are doing that now, but i'd add coil-overs. remove all the leafs but the upper two (since they locate the axle). you know or can find out the weight of the truck front end, each corner, and can find the spring rate of the spring pack. with this information, call a shock manufacturer (Sway-A-Way, Fox, King, etc) and they can set you up with the appropriate spring rates for a coil-over.

the remaining leafs will be doing some support work, but will mostly just be locating the axle both longitudinally and laterally (you may want a panhard bar regardless, like the '99-'04 Superduty's). the coil-overs will be doing the majority of the load support work and ride quality. the upper links will control axle pitch as it cycles through travel range.

if i had your truck, this is what i'd do.

 

[JCole]

MudGuppy, Just an update. After a bunch of mockup work using metal tube from a swingset, me and Dad have decided to go with a leading link suspension. Probably going to do triangulated uppers, or possibly lowers. We'll be putting in a huge cross piece across the frame and using it as both a bumper mount, frame reinforcement and to tie the control arms to. We may still do a parallel link panhard setup, but the triagulated setup might prove to be much easier.

 

[mudguppy]

cool. take lots of pics - i think you're truck looks like an awesome project!!!!!!!!

 

[booger]

What a cool looking truck. I'd like to do something like that on my next one. I suspect there's a bunch of us that would like to see some pictures of how you mounted the cab.