Shocks - Rancho, Bilstein, etc.

[JHanson]

I haven't done it, but aren't airbags more recommended if you are going to be taking the camper off and on?

Air bags augment the springs and help level the vehicle; they provide no damping.

Thom: I'm going to challenge you on your claim about the function of dampers. If the only variable in the dynamic system was the unsprung weight, why would we have the huge variety of valving available to us? The differences in unsprung weight between, say, a short-wheelbase Wrangler and a long-wheelbase Land Cruiser would not be all that significant. Watch a vehicle go over a speed bump in a parking lot, and it will be obvious that it is the sprung weight—chassis, body—that is oscillating after the bump, not the unsprung axle and wheel. Bounce up and down on a vehicle's bumper at rest, and again it is the sprung weight the dampers are affecting. Put the same shock on a RAV4 and an F350 and I'm pretty certain you'd get different results, but the unsprung weight would be completely static.

I can most certainly tell you I feel a difference when I change the settings on the Boss shocks on our Tacoma, yet the unsprung weight has not changed.

 

[JHanson]

Squatch, the Boss shocks (here) are actually manufactured in Australia. I've only dealt with the Canadian importer, but the site lists a few U.S. distributors now.

 

[Stromtrooper]

Just got Bilsteins because of their good reputation. Way way better than stock, only on-pavement testing so far tho.


Sent from my iPhone using Wander The West

 

[Squatch]

Squatch, the Boss shocks (here) are actually manufactured in Australia. I've only dealt with the Canadian importer, but the site lists a few U.S. distributors now.

Thanks I couldn't find any US info on the site I looked up.

I was at Independant4x today dropping off my rear differential to get it regeared. I looked at a couple of project trucks in the shop. A couple had some gorgeous looking FOX shocks on them. These appeared to be non reserviour type and appeared to be rebuildable. They certainly looked very well made and these were street/trail trucks. I didn't really have time to talk about them with the owner.

 

[JHanson]

Fox shocks are indeed superb. I'm not sure—no, I'm sure they're not necessary for the vast majority of the kind of travel we do, but they are impressive.

The best expedition shocks I've ever personally used were Koni Raids, on a 3,000-km loop through Tanzania and Kenya in an overloaded 110. They were magic in their ability to soak up hours of punishment. Sadly they're virtually impossible to obtain in the U.S., and would probably rival the cost of those Foxes if they were.

 

[billharr]

Good spot for this. Bose the speaker guys did a electromagnetic car suspension system. Big $$ and heavy, but look what it could do.

 

[Beach]

Installed a set of Bilstien 4600s on the rear of my 06 Tundra/Hawk 2 yrs ago. They do a great job, very pleased with them..

 

[Riverrunner]

I just put Rancho 9000's on my rig a few months ago and I like them. Made a huge difference in ride too me over the RS5000's that had over 110K miles. At $75 ea I didn't think the price was bad. Over the years on truck forums the Rancho's seem to have a better reputation and a couple friends tried Bilstien's and promptly took them off. Each to their own....

 

[ntsqd]

Jonathan, Which weighs more so which is the more logical frame of reference? This isn't something that I dreamed up. All of my various references on the topic frame their view of damper function this way. It is more a matter of definition than anything else. Everyone talking about it has to use the same reference frame or there will be mass confusion.

The reason that the sprung mass oscillates after a speed bump is because the unsprung mass has been allowed to impart some or most of it's inertia into the sprung mass. Prior to that imparting of inertial energy the sprung mass' inertia had it going flat and level. Notice that it is delayed, the sprung mass' movement only starts to happen after the the tire is past the bump. It isn't the bump compressing the suspension that upset the sprung mass, it's the suspension unloading. So it is not the compression damping that is at fault, it is the rebound damping that is at fault. Or at least is the cause. It is extremely easy to blame the compression damping because that is the direction that you are moved when experiencing such an event, but if you train yourself to look at where that upward motion happens to the sprung mass relative to where the bump is you'll see that the tires are past the bump, so how could the initial compression have caused the sprung mass' reaction?

If the dampers could do a perfect job (slightly over-damped) then that wouldn't happen. But because that perfect damping would only be effective for that size bump encountered at that exact speed there is no point in making it perfect there because it will be imperfect everywhere else. The old "test" for shocks that need replacing is to jump on the bumper and if it only goes up once past ride height and then settles out then they're deemed "good" by that test. That is a perfect example of Critical Damping. Which is what most strive for. In a vehicle that means that some of the inertial energy in the unsprung mass from hitting a bump will be transferred to the sprung mass - upsetting it's perfectly flat & level traversal of the terrain. Put in electronics terms we have a variable frequency, variable amplitude input and we want Critical Damping for it. That's a pretty sophisticated damping function. Velocity sensitive damping is pretty close. If you can add-in position sensitive damping you'll gain that last 10% or so (my guess). Since adding that in is expensive it fails my cost/benefit analysis for a regularly driven vehicle. A race vehicle is a different story.

Having used deflective disc valved dampers for all sorts of types of driving over the last 15+ years I feel that they are the best choice within the U.S. for any purpose. Not that there aren't other good choices too, but on a cost and availability stance there isn't much that can compete.

 

[Captm]

We went from OEM Bilsteins to OME and what a great improvement that was. It was the best bang for the buck that won me over after over researching shocks. I over research everything according to my wife - except her it was a no brainer. Then I stepped up to Icons V.S 2.5 what a fantastic difference over the OME. Yes they cost $$ and are not needed for everyone but for my type of trips they are just what I want/need.
Cheers

 

[ski3pin]

................................I over research everything according to my wife - except her it was a no brainer.

 

[Mickey Bitsko]

Just installed bilstein 4600's on the rear, haven't been off road yet, that will be tomorrow...

 

[JHanson]

Thom, thanks for your thorough and patient argument. However, despite your efforts, I'm still having trouble with this. Consider an experiment in which you drove two vehicles straight off a curb at low speed. Both vehicles have the same unsprung weight—axles, tires, etc.—but one vehicle weighs 3,000 pounds and the other weighs 6,000 pounds. They both have the same springs (or different—I'm not sure that would matter). In essence we'd be doing a moving bumper test, watching the oscillation as each vehicle came off the curb. It sounds as though you're telling me that if both vehicles had the same shocks, they would react exactly the same—same magnitude of oscillation, same number of oscillations. And that just doesn't make sense to me. The same shock would have a more difficult time damping the oscillations of a heavier vehicle. The unsprung weight wouldn't even be a factor. What am I missing?

 

[Advmoto18]

It really is a matter of simple physics which Jonathan has put into excellent plain English. Static v Dynamic loading is a well documented subject; much has been published on the matter. Google for pages upon pages regarding the subject.

I would suggest reading up on Dynamic loading (more precisely, Newton's Law regarding motion) since we are discussing our trucks/camper in motion.