Question for off-road experts

[cranetruck]

Starting to move the 757 around and looking at suspension components I noticed the limiting effect of the shocks, how wrong is it to have an axle suspended by a shock absorber as shown in the image below?
I'm going to run the same test tomorrow without the shocks to see if there is a big difference.

A discussion is welcomed.

 

[nk14zp]

It is hard on the shocks.

 

[Jetnoise400]

The desert racing crowd uses limiting straps to prevent the shocks from being the travel limiters. If enough force is applied, the shock can fail. Bad idea.

 

[gimpyrobb]

I agree, check travel and see if you can find a longer shock that doesn't bottom out when compressed. I would also add a limiting strap. Alot of the offroaders angle the shocks so they have better articulation with a certain length shock.

 

[319]

I'm no offroad expert by any means but I'd be more concerned about the weight of the axle yanking the shock out of the mounts than the shock itself coming apart.

 

[rizzo]

I agree, check travel and see if you can find a longer shock that doesn't bottom out when compressed. I would also add a limiting strap. Alot of the offroaders angle the shocks so they have better articulation with a certain length shock.

x 2

 

[Srjeeper]

Universal joints can get bound if the driveshaft gets to great an angle at the yoke.

 

[dc3coyote]

Pinzgauers have the limiting straps on all axels. I do agree with what everyone has said the shocks are not load lifting.

 

[mudguppy]

limiting straps are cheap. maybe even cheaper than shocks.

 

[alexace]

Limiting straps are a good idea, but replacing the shocks/springs for better articulation is a better solution for the problem. Increased articulation translates to better offroad performance in general.

That thing stock doesn't seem to have much travel, but I bet it would be a beast offroad with increased flex.

 

[cranetruck]

Thanks for the input! At what speed do shocks stop serving a purpose, maybe the bump stops are all that's needed at slow speeds off road?

 

[gimpyrobb]

Never thought of that. Alot of "wheelers" will pull a pin to disconnect their anti sway bars for better articulation. Maybe you could do something similar for your shocks.

 

[alexace]

Yeah Gimpy. On my Range Rover I have removed the front sway bar entirely, and in the rear i have disconnected it but left it in place so if I need to tow something I can use a wrench and put it back on. Removing sway bars really increases flex in the suspension.. The only problem is that it makes the truck slightly less stable at high speeds when cornering. considering this truck probably won't be on the highway too much, you are probably totally fine to take them off, or at least take one off and see how it handles. Because it is has 4 axles I think that it is probably very stable anyway, so taking off the sway bars will probably be almost unnoticeable. In my Rover I drive it the same way I did with sway bars I just cant jerk the wheel suddenly at highway speeds (60-70 mph)

 

[alexace]

Do you have any more pics of the suspension? I'm really curious to see just how it works now.

 

[Travis89xj]

I have broke the shafts on several shocks on my jeep fro the same thing. I too have removed the sway bars on my jeep.

its not a good idea to run off road with out shocks, atleast on a jeep its not, they get really bouncy but on that heavy a truck it might be ok.

like said before though check to make sure your driveshaft u-joints arent binding once you take the shocks off

 

[BFR]

Bjorn,
I can see the value of limiting straps, but I personally would avoid changing shock lengths as longer shocks of the same design will just create another problem (bottoming out the opposing shock)

 

[cranetruck]

Do you have any more pics of the suspension? I'm really curious to see just how it works now.

The spec: "The suspension allows for 4.3 inches of vertical jaunce and 8.8 inches of vertical rebound. Under roll conditions, the wheel can go into 9 inches of jaunce and 8.8 inches of rebound.
It can cross a 27 inch vertical step without interferences."
The shocks have a 10 inch stroke and a piston dia of 1.75.

I have removed the shocks in the rear and will do another run later today.

Note: The m656 cargo version does not have shocks in the rear....

Edit: Added image

 

[ecostruction]

I had this problem on my rover. Blew a shock through flex. Sway bar removed. Sounded like a canon going off. I don't see the point in that shock especially unloaded. If you haul with it, maybe, but unloaded that shock will never work. Springs are too stiff. I'd remove and test or use axle straps. If you are cruising down the road at 55 with it and no shocks you might get slight hop on the rear axle, but, I doubt it. Plus, it's a bogie style setup right? I can't see it hoping then.

 

[Jones]

Bjorn,
Shocks are there to smooth out the ride and help keep you centered in your lane at road speeds.
At 15mph or slower, I wouldn't think there'd be enough up and down suspension motion for your shocks to worry about; unless you're on a stretch of road with severe pot-holes or an exaggerated washboard surface.
Remember, most off-road construction and earth-moving equipment has no provisions for shocks, relying on lower pressure tires for any dampening requirements.

Longer travel shocks are available but may be hard to find in sizes large enough to work properly in all environments. Shocks too small for the loadings will quickly overheat and fail.

I also vote for limiting straps. They could be made to appear very "factory" looking to keep your rig's original appearance.

 

[cranetruck]

Hauling a ballistic missile (mostly on-road) could have something to do with it.
Anyway, it's raining now so I'll drive it again later.