horisontal coilover

[kramkieone]

I'm looking at mounting the rear coilovers horsontally with a lever arm to connect them to the diff after searching I only found 1 referance



this picture

any information on this set up would be helpfull

[Z28YJ]

Some monster trucks are set up that way. Samson is/used to be. Google Patrick Racing.

[extremetoy]

plenty of prople do it in the lowrider scene with bags, search canteliver (sp)suspensions

[yoterford]

what would be the point in doing that except to keep em out of harms way and coolness factor

[kwrangln]

Originally Posted by yoterford

what would be the point in doing that except to keep em out of harms way and coolness factor

By changing the length of the lever arm, you can get alot of travel out of a short shock so its a hell of a lot cheaper than buying an 18" coilover and the springs to go with it. Then there's the easier packaging, lots of folks have trouble getting a shock between the tire and frame with out the shock rubbing something through its range of travel. And finally, on full bodied rigs using a short shock and bellcrank arrangement you dont end up with coilovers going through the body taking up cargo room inside or holes in the floor that let dirt/mud/ice/water through.


Just my thoughts while looking at the pic. I saw that heep at a WEROCK comp last year and thought it was a pretty good idea.

[kramkieone]

Originally Posted by kwrangln

By changing the length of the lever arm, you can get alot of travel out of a short shock so its a hell of a lot cheaper than buying an 18" coilover and the springs to go with it. Then there's the easier packaging, lots of folks have trouble getting a shock between the tire and frame with out the shock rubbing something through its range of travel. And finally, on full bodied rigs using a short shock and bellcrank arrangement you dont end up with coilovers going through the body taking up cargo room inside or holes in the floor that let dirt/mud/ice/water through.


Just my thoughts while looking at the pic. I saw that heep at a WEROCK comp last year and thought it was a pretty good idea.

That pretty much covers my motivation for this idea I still want to be able to take both the kids wheeling and keep it as legal as posible.

[kramkieone]

My main concerns are how the lever arm will effect the spring rate and shock valving( I've spoken to a few local racers who couldn't shed much light on this or recomend anyone who is really good at setting up coilovers).

My other main area of concern is the linkage from the diff to the leverarm couple of people sugested bushings

[dahoyle]

There is quite a bit of actual engineering in an application of this sort. Depending on link the design of the cantilever arm, you could end up with a really sweet setup (one possibility) or a complete POS (a whole lot more likely)

I wouldn't try to emulate a suspension design from a monster truck, because, While I don't know it for a fact, I would imagine they have a lot of rising rate built into the design, to keep the suspension relatively soft at normal ride, but really stiffen the hell out of it at max compression, like right after they clear 2 bent up school buses, and come falling back to mother earth.

You can build one with either a rising rate, which would be good for a coil type spring, or a slight falling rate, better for an air shock, or even one with a relatively linear rate, which is what a typical coil spring in a vertical configuration is. If you have the resources, you can get more out of this type of suspension, than any other, but like I said, for any given vehicle/application, there is only going to be a narrow margin between hitting the sweet setup, and the almost infinite number of really fucked up setups. The real trick is in knowing how you want the suspension to behave, and then designing around it. I'd start out with a linear spring rate, or possibly a little bit of rise in the last 25 percent of travel. You don't want too much rise in a crawler design, or it will not allow the tire to stuff. It is more to absorb hard hits (jumping).

If you have the time to deal with that, go for it, if not, I'd look into something else.

I know a little bit about it, and I wouldn't even consider it, unless I was willing to bring an engineer into the design.

Doug

[Nordic1]

Its called cantalever suspension... You'll see it alot on desert trucks

[OnTheSpot]

I call the "lever arm" a bellcrank. Seen it on desert trucks and a few other small buggies.

Some reasons for doing it are you can use smaller shocks mounted lower.

[Nordic1]

Originally Posted by OnTheSpot

Some reasons for doing it are you can use smaller shocks

Or the same shock to get more travel

[russellmn]

I've done this on a street rod before to get the coilovers behind the grill and out of view, thought about doing it on a buggy, never have though... If you do it, post it up and let us know how it comes out.

[kramkieone]

Originally Posted by russellmn

I've done this on a street rod before to get the coilovers behind the grill and out of view, thought about doing it on a buggy, never have though... If you do it, post it up and let us know how it comes out.

do you have any pictures or further detail of this set-up and if you were to do it again is there anything you would do differently next time

cheers

Frank

[rednecknate]

Ive done this on bagged trucks IE: Lowriders,mini trucks ,and a prerunner,Never a crawler If you have room to run them conventional DO IT>>> the engineering is a nightmare to do correctly.Bags are easy because of changing in pressures..Best way if your going only for clearance is to do them 1to1 ratio "think the shape of a boomerang"that way you can run off the shelf valving and keep rates to a minimum..just my 2 cents..Hope it helps Also the smaller the shock The harder is is on it..Shaft speed,heat,heim load,etc...

[dahoyle]

A boomerang shape would work pretty well but can still be either a rising or a falling rate. The thing about that particular link is that the end that the shock is mounted doesn't move in a straight line, but rather an arc. If you set it up with the bellcrank directly in line with the shock at the end of travel, that is going to give you a rising rate. If you set it up past that point, then the spring rate will be falling off as it goes thru the arc past this point. Again, as I said, you don't really want your spring rate to get lower as you run out of shock travel. A little bit would probably be ok, but too much could have disastrous results (suspension bottoming hard).

It would be the easiest to set up and build, and probably the easiest to get right, but you still need to have some idea of what is going on with rate, as you go thru that arc.

[53guy]

Back from the dead..... Where can one find suspension theory on this? I understand the concept fine enough, but all the details I'm hazy on.... Does anyone have a book or a link to somewhere that explains it a bit? Everything I search either brings up bridges, low riders or nothing useful in the way of theory.

[1TonOfSh!t]

I'm not webster but i think it's spelled horiZontal.

[Dusty Booger]

Sept 2008 Petersen's 4-Wheel & Offroad had an article on this subject. Off Road Evolution makes a cantilever kit for JK's. Check out www.offroadevolution.com.

[psychtoicj]

they use them on rc cars maybe can use some of the ideas from them.

http://www.youtube.com/watch?v=bIJTT...eature=related

they look like they flex good on the small scale but would like to see this applied to a jeep.

[53guy]

Originally Posted by Dusty Booger

Sept 2008 Petersen's 4-Wheel & Offroad had an article on this subject. Off Road Evolution makes a cantilever kit for JK's.

I read that....almost a worthless article....did nothing but describe how to install the kit. I'm looking for theory and design....engineering aspects really.

[600dollarXJ]

Its also a common setup in open wheeled race cars (F1 and the like). We also used it in Formula SAE (college open wheeled race car design fsae.com), but I didn't actually work on the shock setup so I don't know much about it. One issue would be fading if you did any sort of fast bumps for very long. I dont have much to add, just thought I'd give you a couple other places to look.

EDIT: There are issues with shock travel and wheel travel linearity because of the bellcrank. It was something that was studied on the SAE car, and it only had 1" of wheel travel. Designing a suspension like that basically involves learning machine design (movement of rigid linkages), and then applying it to the shock setup. Here is the book we used: Uicker, Pennock, Shigley, Theory
of Machines and Mechanisms, 3rd ed, Oxford Univ Press, 2003

[Weasel]

Ha, I've been working on modeling a cant. lever setting for the rear of my XJ. I've gotten some information from "The Shock Handbook" and Carroll Smith's "Tune to Win". I've been reading quite a bit one it an I'm still fuzzy on the details, but think I've got a hnadle on how to figurout the rate, rising/failing, etc.

I'm just running the shocks on this system and sticking with leaves in the rear.

Also check out Eng-tip forums.

[53guy]

Weasel, I am trying to do the same thing, but I'm thinking of 4 link and coilovers or possibly just shocks as well. Were the books worth purchasing or should I just go to the national library?

[IslanderXJ]

I've been toying with the idea in Solidworks for a while now, so no real world experience here, just observation and theory...

I've noticed a few things while working with it:
To get the best (most useful) rising rate, the shock must be tangent to the the arc of the cantilever arm at full bump (up-travel). Also, it works best if at full droop (down-travel), the shock is perpendicular to the arc of the cantilever arm.
My observation is that the shock attempts to collapse faster at full bump and slower at full droop with this setup, making the rising rate totally obtainable. Soft for the little bumps, stiff for the big hits.
I'm still playing with the cantilever pivot vs. the tie rod(cantilever arm -> axle) mount on the axle vs length of tie rod.

[53guy]

Islanderxj, are you using a 1:1 or a greater ratio lever? Would this have any effect on your findings? I don't imagine so, but that's off of work in my head.