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Discussion Starter · #1 ·
OK... this is entirely Hypothetical (for now) my idea is to make a completly free floating rear axle. Make a one link Rear end, with no solidly mounted springs. Something that attaches (solidly welded) to the rear axle in 4 points (on top, and under the axle, near the current shock-mounts) and one pivot (similar to a pintle hitch), located near (either over or under) the front of the driveshaft. For the springs, i was thinking something like a 1/4 elliptical spring, and then a good size pad (teflon covered) for them to rest on. This would allow literally unlimited droop (limited by shock length, Axle length if you want to get reallllly crazy).


Any plusses or minuses to my idea??
How about any other ideas?? These are all hypotical for now, so give me your Craziest, Off the Wall ideas, I might end up using them for an engineering project eventually

Thanks everyone
BJ

PS, any more Clarificatoin needed on my idea??

PSS, I've read all that stuff about having tooo much Articulation.

"If you chose not to decide, you still have made a Choice" RUSH
 
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Discussion Starter · #2 ·
with a one link rearend how would you control side to side movement of the axle? i think depending on your idea for the one link you need at least 2 more at angles to prevents side to side movement. just a thought. maybe you accounted for that, but i couldnt tell from what i read. good luck if you try it out as an engineering project, i would love to see the autocad drawings for that.
Mechanical Engineering (grades pending heheh)
Texas A&M University
2003 :(

'95 Jeep Wrangler Sahara
33"s, snorkel, 1000+ RTI, Warn xd9000i
 
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Discussion Starter · #3 ·
A lot has been said about having too much articulation. I agreed that it as entirely possible to have too much articulation... until I saw twister in action. For those who aren't familiar Twister is yellow rock buggy owned by Jim Allen here in Phoenix, it is the first tubular rock crawler to my knowledge. Anyway Jim, a really nice guy by the way, built a non-captive suspension for it. it uses one transverse mountted leaf spring on top of the axle which is mounted by a 4 link with long links. The axle can go near 90 degrees. I figured that while looking impressive it wouldn't have enough pressure in the drooping tires to be effective. Apparently no one told the truck this. I watched it effortlessly crawling over giant boulders at the championships. Wow!! I wish I had digital pics to post. It was truly awe inspiring. And as for long travel suspensions tendentcy to fall into holes, I think this could easily be solved by mounting the links in front of the front axle like on Walker Evan's Blazer. I'm currently fiddling with this idea trying to get enough travel out of it. The downfall (or another advantage) of long travel suspensions is the steering problems that develop. Twister runs hydralic steering and I think this is the way to go on a non street driven rig. The final reason I see to run a mondo articulating suspension is simple. I've never seen a truck roll with all 4 tires on the ground. Any thoughts? Happy Jeepin'
Travis

Inquire about my witty original saying contest/wwwthreads_images/icons/crazy.gif
 

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I've been considering this for about 6 months now... and maybe once I go through though my current 31" tires and then a pair of 35" tires I'll have saved up enough to do it. To locate the axle you need 4 controll arms. Two will run right next to the 1/4 elliptical springs and attach to the bottom (or to a plate underneath with a attachment in the front) of the axle in a straight line. Two more will attach just inboard of these arms and connect to A: a single point in the center of the axle, on top (most likely this will be the top of the differential, ala Warn's XCL suspension), or B: just off to each side of the differential, on top of the axle. These will form a V if looked at from top or bottom and should locate the axle laterally, while not hindering articulation, and since one set is mounted on top of the axle, and the other on bottom, axle wrap is eliminated. Shocks should be run in a configuaration similar to the top control arms. The rear arms may need to be bent to avoid smacking them into rocks while drooping (although I dont think are wheel-bases are long enough to allow this). The strange part of my idea was to have this whole affair mounted further back than stock, so the axle actually rested directly under the rear bumper. This would give incredible departure angles, although if you planned on towing things with this Jeep you might want to move the axle a tad forwards. I hope this was of some help to someone and I didn't just type what everyone was already thinking....
 
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Discussion Starter · #6 ·
If you were serious, you could control the side to side axle shift by changing the attachment to the frame. I'll try to explain this...but it may be difficult. Assume that the rear axle is attached to a 4"x4" steel tube...attached to the axle however you wanted, but securely. At the frame, you could have the basic equivalent of a heavy duty spring mount, with a 4" opening in it that the tube could pivot up and down in, but not side to side, and with no rotation (use some sort of very stiff poly bushing). Then, a few inches behind that up and down pivot, have a rotation only joint, no up and down, no side to side. The tube could be cut into two pieces, and connected with a heavy bolt to pivot upon. (make two fists, put them against each other. Now take a pencil and put it between your middle and ring fingers on each hand, still fisted, so that your hands can rotate around the pencil, but can't move up or down). Limiting the amount of droop and the amount of rotation would be very easy, and side to side movement would be impossible, if everything was strong enough.

Trying to come up with a witty line to end all of my posts...
 
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Discussion Starter · #7 ·
hey farm... i am flexing your suspension in my head and its seems to be a pretty good setup, EXCEPT, as the axle rotate with the diff as the fulcrum, like a see saw, the more it is off horizontal, the closer the ends of the links would be horizontally. take a loop of string and hold it with 2 hands, with 2 finger on each side kinda of like that little kids string game... now pretend that 2 fingers are the frame attachment points, the other 2 on the opposite hand are the axle connecting points, and the string itself is the links... as you rotate on hand you can see that the ends on the axle side get closer and closer with respect to the horizontal the more the axle is rotated.. this means that the links need to have some rotational motion allowed like the 4 link does.. i couldnt figure a way that your setup could. if you can figure out what i mean (i know it is hard to understand, it is equally hard to attempt to explain) I love articulation and axle movement conversations, there are so many ways to achieve what tyou want out of a suspension, I wanna hear MORE!!

'95 Jeep Wrangler Sahara
33"s, snorkel, 1000+ RTI, Warn xd9000i
 
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Discussion Starter · #8 ·
Ahhh.. such refreshing thoughts

Farm.. idea sounds good to me, even the fulcrum part...
Lets see if i can explain it a lil better.
make a Solidly attached "Y" (in red on attachment) to the axle with 2 attachement points welded straight on. the 3rd "leg" goes to a twisty joint (Dark blue), allowing rotation, about the center of the axle. Following this, is another joint, allowing vertical movement (light blue).

The axle mounts can be solid.

Anyone else??
BJ

"If you chose not to decide, you still have made a Choice" RUSH
 

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Discussion Starter · #9 ·
That wishbone seems similar to what the scorpion uses in the rear. It would probably work good.

Tim Springer
1980 CJ7
WALSTIB/wwwthreads_images/icons/wink.gif
 

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Hmm,
i've thought about using a '78/79 ford bronco front axle (reverse cut Dana 44) for the rear axle in a jeep using a Spicer 18 (offset) transfercase.
So my idea is use the factory radius arms backwards, with a big "Hemi joint" instead of (radius arm bushings) i think the way the radius arms mount to the axle will control axle twisting (also you can buy different caster bushings for setting pinion/driveshaft angles)
Also needed is a way to control axle side to side movement, and trackbars/panhard bars will limit extreme articulation (i think). so my thinking (or copied idea is to build a solid "V" with 3 Hemi's and mount the V point above the axle diff. and the 2 forward ends somewere between the front U-joint and the radius (now called "trailing arms"?) mounts. (i think the location would be very imprortant)
of course i would also make a 4-wheel steering system /wwwthreads_images/icons/smile.gif

3/4tonYJ
My Jeep Page
 

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/wwwthreads_images/icons/crazy.gif You want insanity? OK how's THIS/wwwthreads_images/icons/crazy.gif You use the triangular wishbone with a big ball joint under the transfer case. The suspension is two HYDRAULIC cylinders with the rod ends down. The cylinders are mounted in their own spring buckets with coil over. The oil compartments are cross-plumbed so that as one cylinder extends, the other can retract. Side to side play is controlled by a scissors in the center, ball-mounted on the axle. You have an electric solenoid to cut-off the cross-plumb line for non-articulation driving/wwwthreads_images/icons/crazy.gif One of my hung-over moonguys/wwwthreads_images/icons/crazy.gif just came up with that./wwwthreads_images/icons/crazy.gif

CJDave
Quadra-Trac modified by the crack moonguy/wwwthreads_images/icons/wink.gif/wwwthreads_images/icons/smile.gif/wwwthreads_images/icons/tongue.gif transfer case team.
 
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Discussion Starter · #12 ·
I don't know if anyone here has seen the running gear off of a farm wagon or hayrack..but...while they don't have the joint to allow up and down pivoting, they do have a very h/d rotational pivot. The front and rear are solid beams (with a provision for turning the front, but that's unimportant for this scenario... Picture two solid axles about 10' apart. Coming back from the front axle is a round tube, about 4" diameter. Coming forward from the back axle is a round tube, slightly smaller in diameter (just large enough to fit inside the tube from the front.) The front tube ends, cut off squarely. Cut into the top of the front tube, about 4" away from the edge where it ends, is a slot that cuts out the top 180 degrees of the tube, about 1" wide. The rear tube is slid in the front tube until it is past that slot. A hole is then drilled in the rear tube, through the slot...but just through the top of the rear tube. That hole is threaded, and a bolt is screwed in (a bolt with a head that is just under 1". Now...if the axles are on uneven ground, the bolt can slide laterally in the slot until it reaches the end of the slot, where it stops travel. The rear tube is prevented from moving fore or aft because the bolt is just narrower than the slot is. There is no up and down play, because the tubes are sandwiched tightly. Get it? To this we add our up and down "spring hanger" joint...and some sort of heavy duty bushings. We can control the amount of droop with a limiting strap at the spring hanger joint, and can control the amount of articulation by cutting the slot a different width. This eliminates the problems that concerned jeepman...remember, we are working off of only one arm...not two. If we make the completed assembly attach right by the rear of the transfer case, as CJDave said, we could have our suspension perfectly parallel the driveshaft...although because it would have to be either higher or lower than the driveshaft, there would still be some extension/retraction in the driveshaft.

Trying to come up with a witty line to end all of my posts...
 
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Discussion Starter · #13 ·
WARNING: long winded dreaming post
3/4 ton yj,
I've also been dreaming of 4 wheel steer for quite a while. I think I'm going to set about building a rockbuggy with 4 wheel hydralic steering for competition when I get my Jeep done. Here's what I was thinking...Now my dad works for Gradall Co. (hydralic excavators and material handlers) and has a pretty good working knowledge of hydralic systems so he can help where my knowledge ends. Now if anyone is familiar with the Gradall shooting boom excavators they'll know that on the rear axles the tires can go 90 degrees, this would make for some extreme capabilities for getting out of trouble on the trails. Now my original plan was to run a full hydralic buggy, cummins diesel hooked up to a huge hydralic pump, four wheel indepedent suspension using huge a-arms and pnuematic struts linked side to side. I also wanted to run hyrdalic motors on each wheel with individual cylinders to steer each tire to 90 degrees. Well that was the dream, unfortunately the cost was prohibitive to say the least, and apparently the gradall axle assembly has several patents. But if I could do it I think Overkill Offroad would be in the winners circle at every competiton around./wwwthreads_images/icons/smile.gif But I have a slightly simplier and slightly obtainable goal. First off I think a diesel is a must have. Torque is good /wwwthreads_images/icons/smile.gif, Secondly, a good steering system is a must. At the phoenix championships a few weeks ago almost every vehichle had steering trouble at the obstical I was on. A few trucks had the driver and spotter hanging on the steering wheel trying in vain to get the wheels to turn. Now making a 9 point turn is a sure way to rack up points in these competitions. I've been in simular situations on the trail and I'm going to try hydralic steering, and while I'm at it I'm going to go for 4wheel steering. Now my dad says he can get me a valve off one of Gradall's material handler's to allow me to select between front steer, crab steer, and 4wheel steer. Know the simple addition of another valve will allow rear wheel steer only. I'm thinking gm or dodge dana 60 up front, and a ford 60 front end in the rear. 4links with pnuematic struts linked side to side for suspension and a dana 18 tcase. I was also thinking of running front 2.5ton rockwells on both ends, but I'm waiting to see how Avalance Engineering does with getting the brakes out of the way.

Here's a few more dreams I haven't had time to explore yet.
Mounting the reduction unit off a Quadratrac tcase on to the pto port of a model 18 tcase. CJDave can your crack moonguy squad help?

Also I was thinking of getting the longest travel air shocks I can find and linking them side to side trying to get pressure on the drooping tire.

Just a few of the ideas that have been rattling around in my head for awhile. I also have a setup currently in development that I think will help out a lot of amc 20 and dana 44 owners who want to add track width, full float, and disc brakes for cheap. I'm hoping this will cost less then $400. Once I get the prototype installed on my scout and beat the holy crap out of it I'll post it here and give y'all first dibs. Anyway I hope I didn't bore you too much, keep those ideas flowing. It'd be cool if we could beat the gun posts with Jeep stuff. Happy Jeepin'
Travis

P.s. 3/4 ton YJ, the inhibiting factor to ford radius arm articulation isn't the radius arm bushings it's the c-bushings. That was the point of my post before I started rambling./wwwthreads_images/icons/crazy.gif

Inquire about my witty original saying contest/wwwthreads_images/icons/crazy.gif
 
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Discussion Starter · #14 ·
By the way, DmsCJ7, that picture is of Jack McCullen's CJ5. And Samarai's can be cool. I'm helping my buddy with his Sami right now. When it's done it'll be sporting a Toyota driveline and axles. It'll be cool. I used to hate sami's until I wheeled with them. Those annoying boogers just fit everywhere. But Jeeps rule /wwwthreads_images/icons/smile.gifHappy Jeepin'
Travis

Inquire about my witty original saying contest/wwwthreads_images/icons/crazy.gif
 
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Discussion Starter · #15 ·
If anyone is interested in seeing Twister in action go to Rockcrawler.com and click on the birthday bash.
Travis

Inquire about my witty original saying contest/wwwthreads_images/icons/crazy.gif
 

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/wwwthreads_images/icons/smile.gif The Quadra-Trac gear reduction unit is surprisingly similar to the Saturn overdrive in that the input is internal and the output is external. If I were building for extremes, however, I would want to go with Bull-Gear axles instead. Planetary axles are nice, but the ground clearance doesn't improve, whereas with reduction gearcase axles or IRS gearcase hubs, it would. Plus, you can run inboard brakes which are "up-ratio" and that is a big help as well. So you have IRS, with inboard brakes...shafts to the outers which have a gear or chain case to the hub. No brakes out there, less unsprung weight. There are OODLES of gear cases like that around. I was in a salvage yard and there were a slew of junked wind generators. They were relatively new, but were flops in some way so they junked them and they had some dandy gearboxes on them. GET OUTRAGEOUS!!/wwwthreads_images/icons/crazy.gif

CJDave
Quadra-Trac modified by the crack moonguy/wwwthreads_images/icons/wink.gif/wwwthreads_images/icons/smile.gif/wwwthreads_images/icons/tongue.gif transfer case team.
 
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Discussion Starter · #17 ·
Not a bad idea but if I were going to run independent suspension on a rockcrawler it would only be with my hydralic motor idea. But seeing as how I don't play the lottery I doubt that'll happen any time soon/wwwthreads_images/icons/frown.gif. I was thinking about trying to track down some unimog axles to put on my buggy. But seeing as how everything to do with unimogs is $$$$$ I haven't done more then dream. I saw a picture of Jeep a soldier in europe built with unimog axles, It had tons of diff clearence. My mom has a friend who is in the military surplus racket, He mainly deals with planes but I've had him track down stuff before. Maybe he could score some unimog axles for me, Hmmmm. If nothing else I'm sure he could get me some reduction hubs off a humvee. steerable unimog axles front and rear with the "slow" gearset, hydralic steering, and some 44s. Drool/wwwthreads_images/icons/tongue.gif I think it would spell V-I-C-T-O-R-Y. Oh well next time championships come to Phoenix I plan on competeing, I'd like a fully twisted buggy, but with My best bud Mopey spotting I think we could make a showing in my Jeep. We'll see
Happy Jeepin'
Travis

Inquire about my witty original saying contest/wwwthreads_images/icons/crazy.gif
 

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/wwwthreads_images/icons/tongue.gif You could market an after-market offset gearcase set of axles. That way the axle shaft spins at a much higher speed, and the whole gear train benefits. The money you made with your company will buy you a super-twist hybrid Jeep./wwwthreads_images/icons/crazy.gifLook at an older farm tractor sometime. They had the clearance problem, the torque problem, and the brakes [problem figured out a LONG time ago.

CJDave
Quadra-Trac modified by the crack moonguy/wwwthreads_images/icons/wink.gif/wwwthreads_images/icons/smile.gif/wwwthreads_images/icons/tongue.gif transfer case team.
 
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