couple of 4x4 vans in idaho falls idaho.

[carringb]

Originally Posted by shenrie

i dont understand was a proper load path is.

Basically, steel members are really strong in tension and compression, but not so much in bending. Bending concentrates the load into a small area of the total cross section. Ideal suspension designs keep control arms out of bending. OEMs however often compromise, and instead they alter the profile to also take bending loads. For example, the Ford IFS uses I-beams because the springs are inboard of the load (the tire contact patch). This requires much heavier components than if the load went directly into the spring. Coilover suspension and even McPherson strut setups can pretty close to direct load paths, which allows for less unsprung weight, and also reduces resonant loads, like you get when a beam flexes.

In the case of those vans, the braking moment (i.e. torque on the axle applied by the brakes) is on the magnitude of several tons. This force pushes on the lower control tube putting it in compression, while the upper tube is pulling. Since its pulling on the middle of the lower tube, its applying a bending force, essential pulling the middle of the lower tube upwards. Add in some transient forces like some wheel hop or a bump, and you can even higher loading than braking alone.

Since I haven't seen those vans in person or done any sort of analysis, I can't say for certain it won't work. But if they haven't done their analysis or testing, they can't say for sure that it will work all the time. I sure wouldn't want to become their test driver by buying one of those vans.

Ramsey's pic looks like the exact same setup duplicated in those vans. It works fine under a jeep because they weigh much less, and have MUCH smaller brakes especially in the rear. This van's don't even look like the control arms were scaled up to match the heavier weight of the vans.

That design could be made much stronger without using larger tubes, simply by using larger clerics or adding a truss to the opposing side of the clerics. Or by using square tube. Or larger tubes. Or the load paths could be vastly improved by mounting the upper tube to the frame ala Quigley.

BTW - I don't know for sure what setup was under the MRAP in the video. But I've seen similar failures first hand in smaller cars because the load analysis was insufficient.

[shenrie]

^^^ if we had a reputation button, yours would be maxed out. thank you for always taking the time for explainations like you did above!

Originally Posted by carringb

That design could be made much stronger without using larger tubes, simply by using larger clerics or adding a truss to the opposing side of the clerics. Or by using square tube. Or larger tubes. Or the load paths could be vastly improved by mounting the upper tube to the frame ala Quigley.

i did an image search on clerics but all that comes up is pictures of wizards and dungons and dragons looking crap, lol. is the clerics the actual piece from point a (axle) to point b (fame)?

anyway, what i picture is something like this:


i know thats not the right part, but its got a truss for re enforcement (and my pic searches are not working in my favor this morning). so if he offered something like that on the underside of the bar would that help? not saying that would fix his design, more or less trying to comprehend where your coming from on where the design is weak and what ways he could improve it.

i also wonder if you think that design would be ok for the light duty offroader? i know the amount of weight you carry with your rig that you wouldnt be willing to try it out, but what about someone like myself that would only be hauling a small utility trailer with a few bikes in it at the most? would you feel comfortable using that setup in a light duty appplication, or is it just the amount of force the brakes on these vans can generate that concerns you?

i heard back from derek. the van was 2wd when he converted it, so he didnt get a chance to drive that setup. would still like to hear from someone who has driven one of these vans converted by zahes lot though.

[carringb]

Originally Posted by shenrie

i did an image search on clerics but all that comes up is pictures of wizards and dungons and dragons looking crap, lol. is the clerics the actual piece from point a (axle) to point b (fame)?

anyway, what i picture is something like this:


i know thats not the right part, but its got a truss for re enforcement (and my pic searches are not working in my favor this morning). so if he offered something like that on the underside of the bar would that help?

Haha I didn't even noticed it got corrected to "clerics". It was supposed to say "clerics". Dammit "Clevises". I just got a new laptop, so I'm not use to this much autocorrect. The part where the rod end from the upper tube connects to the lower tube is the clevis.


But yeah, you're on the right track. In this case, it wouldn't need anything near that elaborate. A simple 1"x2"x0.25" C-channel welded to the bottom of the lower tube would add a tremendous amount of strength.

And it's not even the off-roading I'm worried about. It's hard braking on dry pavement.... I.e. panic braking on the freeway, when you're really standing on the pedal. Maybe 4-lo with the diff locked might come close to the same moments (but opposite), but a buckling failure while rock crawling is unlikely to be as catastrophic as a buckling failure at freeway speeds, and while rock crawling you probably won't have as much grip under the tire.

[shenrie]

ha! ya im familiar with clevises... too funny. so ya, i understand what your trying to say and makes complete sense. appreciate the clarifications good sir. id be more concerned during a high speed brake than a low speed rock crawl as well. these vans arent light...

and yes, i know that pic was total overkill, but thats the only pic i could find with the bracing style i was picturing in my head. ill mention the idea to him next time we talk. im still waiting for the mail with all the 4x4 specifics.

as always, appreciate the spoonfed responce

[jage]

Don't be knocking D&D now

[shenrie]

lol, no disrespect intended. promise

[fourdown]

If anyone is interested i can shed some light on these conversions. From the horses mouth!

[bigskyguy]

Originally Posted by fourdown

If anyone is interested i can shed some light on these conversions. From the horses mouth!

I'm interested. Also Interested in contact info for the van.

[shenrie]

^^^ sorry, link is now down in original post. lot info:

Right Price Auto Sales
1480 N. Woodruff Ave
Idaho Falls, ID 83401
Ph. 208-535-0920

http://www.rightpriceautoid.com/

fourdown, are you the builder?

i also think one of these vans from price right was staying at the same campground as us around aug 17th just under palasades. a buddy told me about the rig, but when i went looking, they had already loaded up thier boats and were gone.

[BroncoHauler]

Originally Posted by shenrie

Right Price Auto Sales
1480 N. Woodruff Ave
Idaho Falls, ID 83401
Ph. 208-535-0920

http://www.rightpriceautoid.com/

Loose the fiberglass running boards, throw in an Agile or U-Joint 4x4 conversion, and this one could be interesting. Priced too high though IMO.
http://www.rightpriceautoid.com/2006_FO ... 464650.veh


Herb