For those of you who take your trucks offroad, do you like the solid rear axle? Are the advantages of a solid axle worth the increased vulnerability?

If anyone isn't initiated in the pros and cons of independent suspension -vs- solid axles, some basic differences exist. With solid axles, when one wheel goes up it forces the entire truck up in the air, effectively increasing clearance. Alternately, if one wheel winds up over nothing because the truck is on uneven terrain, a solid axle will force a wheel down where it can touch something solid and get some traction. You may have seen pictures of jeeps with one wheel way down low and the other wheel way up high, they call this suspension agility or flex.

Those are very nice advantages for some offroad situations, possibly (i have practically no adult experience with solid front/rear axle vehicles so i'm thinking about it more than relating experiences).

The advantages of independent suspension can sort of be understood by looking at the front -vs- the rear of the H2. The minimum clearance of the front is about 12 inches, while the rear is about 10 inches. Further, on the factory truck a nice skid plate covers all the innerds of the truck and only those arms attached to the front wheels are exposed to take a hit.

The rear end, on the other hand, is basically a sitting duck. Only if one tire is on a rock does the clearance advantage i described above occur, and if a rock happens to be between the wheels, the differential housing takes the blow (as the front skid plate often in my experience clears rocks that smack the rear diff, forcing me to drive slow and be careful).

So, i think that its reasonable to say that with independent suspension a truck that is less vulnerable to rock damage / impact damage can be had. Provided that the armor is up to the task. In the case of the H1/Humvee, this is taken one step farther as the unique design allows almost no possibility of hitting a moving part.
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On the H2 the front drive parts aren't tucked up as high as the Humvee, but I have some DIY armor that a friend and I put together that is basically invulnerable. I've just crushed it on rocks and it just scratches the paint (it does weigh about 200lbs though).

And I, for one, would take some DIY super-armor and an independent rear in a heartbeat. I'll give up a little bit of clearance in some situations for protection in any situations, and i'll just slide the truck over a mound of rocks on its belly (which could then be all armored) -vs- trying to wiggle my way over to protect my rear diff.


Jeepers swear by solid axles, and the US Military has sworn by 4-wheel independent suspension for decades (M151 and Humvee).


Thoughts appreciated.

 

The solid axle has major benifits over an independant design in strength and durability. The independant setup has many moving parts and all are made of thinner, weaker materials that a comparable sized solid axle. The independant setup also looses ground clearance when one tire is on an obsticle. The solid axle will take an impact that will break independat components such as ball joints. The centersection can actualy go down a slight amount before it starts to go up, where as the entire assembly will go up with the solid setup. Another drawback is the limited articulation offered by the independant desin as you were leading to in your post. The independant stuff just doesn't move like the solid stuff. The independant setup has a benifit of a smoother ride, but compared to the simplicity, parts availability, and strength of a solid axle, it doesnt offer any other gains.

The M151 and HMMWV are both designed by AMGeneral, and I would believe that is the only reason they both have independat suspension F&R. I doubt that was adesign criteria the military imposed when they put out the design request, unless it was chosen for parts interchangability. The suspension setup on th HMMWV is interchangable from front to rear. Everything else in the military, except for the new 7 ton truck the Marine Corps is using has solid axles. It by the way, does have independant suspension at all 3 axles.

In my opinion, give me solid axles any day.

 

i'm fairly sure that IDS was in the military spec both times. i don't have time to google for where i've read that, but i'll post a link when i can.

with respect to the durability, twice in my life i have bent solid axles, and only 1 broken drive shaft for an independent suspension. And a bent tie rod that happened at the same time as the broken shaft.

I hear what you're saying about the mechanical components, but where i offroad surprise rocks that you can't see through brush or snow or grash are commonplace, and my rear diff isn't nearly as capable of taking a blow as my front skid plate.

 

Although I've never worked on the HMMWV, the H1 does not have interchangeable half shafts front to rear. It has 3 different size halfshafts, only 2 are the same size, and i believe it's the 2 in the rear that are interchangeable.

 

the mercedes G500 gelandewagen is solid axles front and rear
the jeeps are solid front/rear (cherokee, wrangler)
the old land rover defenders were solid front/rear
i know pickups used to be solid front/rear, because my brother and i kinked the front axle of our old mans pickup so badly that we briefly contemplated leaving the country rather than facing the music

now pickups are independent up front, solid in the rear, i think. mine is anyway
the H2 and H3 and Tacoma are independent front/solid rear

The VW Toureag and new Land Rovers are all independent, but not really independent in a way that's meant to offroad as clearance is really limited and underbody protection isn't really there.

And that leaves basically just the M151 and the Humvee/H1 that are independent all around and nothing hanging down to get damaged.


Does it seem to anybody else that independent front/solid rear is more worst of both worlds than best of both worlds?

 

The left front and right rear suspension is the same, as is the right front and left rear, i.e. A arms, tie rods. The geared hubs are the samefront to rear, right different from side to side. I dont recall the half shafts being different length. We always had at leat two with us, and we never had any problems reguardless which ones we broke, although the most common ones to break were the front ones for some reason.