Solid axle vs. independent in off-roading

[Chris Turner]

Okay, I'm confused:



Why is a solid axle preferable to a fully independent suspension when off-roading?



To my thinking, with independent suspension you gain ground clearance no matter the method of lift: suspension lift or larger wheels & tires. With a solid axle, as soon as the lowest point on the frame is higher than the differential, your axle becomes the limiting factor in ground clearance... so the only way to increase clearance would be with larger wheels and tires.



Have I missed something?



Also, does a body lift somehow change clearance, or is it just for looks?



Thanks for the education!

 

[Chris Turner]

Rats, meant to post under the Suspension topic. My bad!

 

[Jerry Gerner 2]

The only why to get true ground clearance is taller tires, BL or suspension lift will only raise the body/ frame higher off the ground. Tires lift the suspension up higher for true lift. Straight axles are stronger, and can be lifted many ways. IFS is limited by CV axles shafts and angles unlike straight axles.

 

[Tom Schindler]

One word...



Articulation!

Tom

 

[H D]

Jerry and Tom are right on. Strength and articulation are the two greatest advantages to a solid axle.



I had a post deleted for menitoning this information for somebody considering the differences between a Gen1 and Gen2. Since he mentioned going off road, I thought it was relevant. I was afraid to post a whole topic concerning it so as to not offend anyone.

 

[Chris Turner]

What you say makes perfect sense. Thanks! :haveabeer:

 

[Johnny O]

You can't get as much travel with an independent suspension as you can with a solid axle, geometry being what it is. With an IRS or IFS you essentially have two axles, each half as long as a solid axle. A solid axle can pivot about the differential as much as the lift and springs and shocks will allow. With an IRS or IFS travel is limited by the control arms, which are much shorter.



For a point of reference, the Dixon Bros. Gen 1 long-travel setup requires wider fiberglass front fenders because to get more travel they had to make the control arms longer.

 

[Gavin Allan]

Why are Hummers independent suspension, then?

 

[Tom Schindler]

Why are Hummers independent suspension, then?

Good question. The reason is because the government needed something that would work in all situations. The Jeep above is specialized for rocky terrain, where the Hummer is good for rocks, desert, mud, etc.



I would be willing to bet the Jeep above is better at what it was designed to do than the Hummer would be. But the Hummer would beat out the Jeep in a composite course that includes everything.





Tom

 

[Johnny O]

Why are Hummers independent suspension, then?

Hummer H1's also have Torsen differentials front and rear except for Border Patrol models that have Detroit Lockers (less training and not as complicated to drive). If you hang a tire then the wheel on the ground will still drive it.

 

[Dreman]

Hummers are also much wider, allowing space for the longer suspension arms.

 

[Yardsale]

From Wiki: The High Mobility Multi-Purpose Wheeled Vehicle (HMMWV) uses independent suspensions and portal geared hubs similar to portal axles to make for a full 16 inches of ground clearance.



With the portal gear setup, the half axle enters the hub at the top, not the center (there is a ring and pinion setup in the hub) and the brake disks are mounted at the differential, providing more clearence.