Technical SUSPENSION, A-bone question

adam..i think thats a kinda sway bar since it looks like hes running a 40s spring..and most of them had those...looks like he just applied that to the rod.

 

Here's a bit of clever thinking that's going on an about 1700# T roadster with built flathead.

Welded to the axle is a ring with channel sides to retain the pivoting piece that bolts it on.
Installed when the axle ends were off.

The outer ring that bolts the split wishbone to the channel ring is two pieces with a step or overlap that is held together with a bolt at each end - 180 degrees apart.

The thinking is this will stop twist at the split wishbones - which are parallel with and outside the frame rails & connected with the larger (3/4") truck tie rod end.

Torque will be controlled by the short torque tube which is perhaps 30" long.

Looks like a viable deal to me and my only criticism is the moving rings are both made of steel and may wear fast.
The guy doing it doesn't think it will if kept lubed.

 

Here's an overall view of the rear axle noted above.

 

Excellent idea ! It may wear after a VERY LONG period of time but, as long as it's kept lubed, it is an idea that's superior to most setups I've seen. The only problem I see is, as the chassis rolls in a turn, it may try to put a slight twisting force in the side-mounted wishbones. Probably not enough to cause any long-term damage.

 

I think the tie rod ends will allow body roll with no probs.
for the most part anyway, they do have a limit and the car does have transverse springs front and rear.
Not sure if they're going to do a sway bar or not, but a light duty one could be a good idea.

 

C9....Assuming the side-mounted wishbones to be both mounted level, when the body rolls in either direction it tries to pull the axle in a forward direction. Unless the torque tube has a slip joint in it like the old Chevy ones, it will not allow the rear axle that forward movement. That's why I advocate a center-mounted torque arm with two spherical rod end bearings at the forward end. the rear can then follow the path(s) dictated by the wishbones without bind.

I agree that a light roll stabilizer bar should be used.

 

That ain't just a bar welded in between the wishbones. There is a large U bolt going around the "pinion" on the front side of the banjo. It's in essence tying the rear end back in to the equation in a third point.

Now, the wishbones are preventing the axle from turning side to side under the car (don't want artifical quadra-steer!) and the bar welded under there prevents the rear axle from rolling or buckling under

 

Yews but you're still transfering all the rotational torque of the rear axle housing [under acceleration and deceleration] to the front of those poor wishbones. Hope the bones are thick-wall tubing.

 

adam , looks like the guy tried to beef it up a little after converting it to a open drive line . lets hope he didnt need to becourse he is putting the force on the side of an unsupported tube an then he does it again by welding that tube to the whishbones , check out the panhard bar mount , scary shit! c9 , that is cool , almost exactly what i was trying to discribe as my plan B . nicely done too .

 

Elrod, that setup is not the best.
The rods are still subject to severe bending stresses when you accelerate in 1st.
A simple torque rod from the front of one or both of the radius rods to the top of the diff would beef things up a treat.
the hotrodworks market such a device.
Mart

 

Getting some good tech stuff here. Any more ideas?

 

This threads timing is great for me, as I'm doin' the rear on the Quad Mod. The look of split rear bones is atractive, but the geometry is bad. Space becomes a problem in a low narrow car.
It helps to build a model for these kinds of things. Using a wooden dowell, 1/2 " dia or so, and some pieces of plywood with the dowell dia drilled into them cut to replicate the planned brackets, one can test a variety of ideas.
The tourque arm idea works OK, but the arm tends to twist, which may result in fatigue and failure. The part could be cheaply replaced as a maintainance item ,though. A 3 link with a common pivot point works very well too. Both systems have to fit between the seats in this case so the are not the best options. A 3 link with a Y shaped link at the top has potential if the room is available AND would allow for the split bones look. Alas, I have not the room.
The next test on my agenda is to sort of copy my old Austin Healey. Since the plan has been to use 1/4 eliptic springs, they can be used as two bars of a 4 link. The Ford radius rods can then be used as the upper links, using thier entire length for the look of split bones. The geometry may be no good, though, as the rear will rotate with the differing arcs, which would be quite a bit.
Does anyone have expeirience wit the Y link or the 1/4 eliptic/4 link with long radius rods? My models won't tell me what real word knowlege would about ride, and traction.
The Frank Mack car and maybe the Steve Grimes mod had solid mouned bones or raius rods. Does any one have good knowlege of those cars and the reliabilty of them?

 

I've got some ideas on split bones using a version of the "wristed arm" used on a lot of high lift Broncos. I'll draw it up tonight and post it.

Meanwhile, search the web for "Wristed Arm Bronco"

 

Hmmmm....I dunno Modernbeat!
I respect your opinion but that setup has issues...
High potential for wheel hop, DOUBLED torque loading for the solidly attached wishbone...
Do you intend to set it up as lockable, like the guys with the Bronco's are doing?
Actually, the Bronco system gives plenty of articulation as-is for a street driven vehicle. A little FUNKY on the axle attachment...but workable!

Ya know what would work? With no bad manners...good flex...no welded joint near the axle to fatigue and fail from torque loading etc...etc?

Land Rover(?) I beam control arms!

And as my brain twists...I see heavy wall wishbones, complete with TWO inline rubber bushings, (a small diameter front bushing paired with a larger rear would be best), at the rear attached to 360 degree double shear plates around the axle housing.
Done this way, bones COULD be run parallel to the frame without articulation issues...without fatigue issues and would still be able to control wheel hop to a fair degree.
Sorta like this...

Pic is crappy but you get the idea...
Small bushing at front of axle keeps the bone thick enough to be reliable. If more strength were needed, the bone could be braced with plate internally, before the bushing tubes are installed.
Parallel bones, with flex and strength!
What do ya think? Workable?

Bill

 

cornfield rodder....The torque arm with double spherical rod ends does NOT twist at all !

 

SJ,
Yeah, I figgered that out, my model used a common bolt for mounting. It was late and I wanted to save time so i could get to bed. Sorry for the miscalculation.
I like the idea of the soft mounted radius arms. Wonder if wheel hop or bushing fatigue would be a concern?

 

I don't think it would be Cornfield. Think of the beating a regular leaf spring bushing takes over its lifetime. Mercedes G wagon and some versions of Land Rover have been doing it like this for years!
Wishbone strength is the biggest concern I can think of. (The OEM builders use I beam like arms.)
Internal gusseting should solve that for all but the most powerful vehicles. Have to be damn powerful too, to bust the braced bone!

Bill

 

Hacker , that should work , where does the spring go ?

 

Depending on the axle used... the shear plate(s) could be designed with a spring mount built in.
Hmmm... might be an issue with a rear mounted spring constantly loading the bushings... Quality OEM suspension bushings would handle the stress OK,IMHO.
Naaa...shouldn't be a problem... those type bushings are used in leaf springs and see loads of weight ALL the time!

The bones could also be used to actually mount the spring...Like a 36 setup...That would work fine with no issues to speak of.
Top mounted spring should be no problem either.
Naturally, some early rears had the spring mounts in place already.
Anyone see anything I'm missing here?

Bill

 

Okay, here's what I was thinking of.

The first setup in the image is a modified version of the stalwart '36 design. I replaced the bolts that connect the arm to the axle with spherical bearings. Using two bearing in line with the arm keeps the axle from being "floppy" at the end of the arm like most Bronco Wristed Arms.

But, that '36 setup really concentrates the torque at the front conection point of the axle and threatens to bend or break the arm during heavy accelaration or braking.

So, I redesigned the attachment plate to line the attachment points up with the axle to lessen, but not eliminate the rotational stress. Then, I'd make the arms out of something very stout and twistable like a pair of straight Econoline I-beam front axles. Weld a gussett to the back end that sandwiches the spherical bearings and a heavy duty tie-rod end on the front.

To simplify it a little, bushings could be used to replace the "traditional" tie-rod end and the spherical bearings.

 

i think i would only use one soft bushing per bone , so the axle can only rotate a bit , and not move up and down .and then put the spring on the bone behind the axle . and the shocks on the axle

 

Hmmmm.... Looks like we're on the same track!

Can't see the sphericals working... Won't allow missalignment in the vertical plane. The main issue is to allow some movement up and down at the front end of the bone if its mounted to the rear axle...fully split.
The Bronco guys addressed it by hinging one arm at the axle. With two sphericals and two bolts on the axle end of each arm you won't get the hinge effect.
Rubber bushings have enough elasticity to flex over and over, in multiple directions, with no wear or noise. They give a built in hinge effect to the locators...without the looseness of an actual hinge!
Maybe a combo of a spherical and a bushing? Big bushing at the rear and a spherical at the front axle mount...with another bushing or a tierod end at the very front?
I dunno...I'm a bushing fan just for the durability!

Bill

 

I've seen this used on a few high-articulation trucks. It's a modified version of that slip joint version shown above.

This slip joint on a CAE front axle on Cotton Werksman's car prevented axle bind. The opposite wishbone was bolted rigidly to the front axle. The same setup could be used on a rear axle.

 

Unless I'm missing something, having a hairpin type radius rod attached to the axle with a bracket that is able to rotate would certainly do away with axle bind problems, but the radius rod could equally be just a single rod. Problem is, it would just look like something is missing. I think AV8 referred to Kent Fuller using a 3 bar setup on some dragster front ends.
Mart.

 

ALL modern sprint cars use the 3-link design on the front axle. 2 on the right and a single on the left. The reason is when the chassis rolls to the right in a turn with a 4-link and a panhard bar, it lifts the left front wheel off the ground. This is NOT a desirable situation. It proves that the 4-link/panhard combo has a built-in bind. The street rod 4-link setups use urethane bushings to lessen that bind but it is still present. In fact, that bind acts as a roll stabilizer because it only allows a minimal amount of body roll before the bind kicks in.

 

Oooohhh.... I think I get you now Modern!
I didn't realize that you meant for one of the shear plate assembly's to mount like that...able to rotate around the housing!

The solid mounted bar would be transfering ALL the torque to the chassis...is that workable? Could cause some weight jacking...although with a long bar...I guess it would be controllable.
I wonder would it make the car dart under braking or acceleration? Wheel hop on the hinged side?

Still...Cotton Werksman had it on those 2 little Mod's so maybe it's a non-issue!
Have you ever seen it on the rear?

Actually...I might have!
I know Soni Honneger had a Mil Jeep with something like that only different.
Offset diff allowed him to build a "Y" shaped link that was mounted flat with a donut bushing at the frame and two regular bushings tabbed to the axle. That link controlled side to side movement and located that side of the axle, front to rear. On the side with the diff he had what was basicly a ladder bar to control torque and location...a donut bushing at the frame and reg bushings at the axle.
NO other links were necessary to control the axle! Two frame bushings held the whole front end. NO Panhard rod either! I THINK the rear was much the same. (Offset diff as well...)
Articulation is a much bigger issue for the 4x4's than for us... Our total would only be in the area of...8-10 inches???

I still like the 4 bushings myself. It's proven under some high dollar rides and it has no potential for metal to metal wear. Sure would be nice to have all that room in the middle of my chassis!
Sunken floor and lots of head room! Hmmmm......

Bill

 

Totally different track here....

How about adapting the SPRINGPLATES from a VW?

Don't use the torsion bars, just the locating arms. By using a sheet or two thinner peices of spring steel you can introduce bending in a single dimension and twisting to make up the reduction of track width relative to the frame when a single wheel is raised.

As a bonus, they can be used in a fairly short, compact area like the area behind the cockpit of a modified that's received a serious Z in the rear.

Don't want to use VW parts in your Ford? I don't blame you. Just use the principal instead. Make your own spring receivers for the axle and the front attachment point. You can use spherical bearings, urathane, tie-rod, heim-joint (which is just an adjustable length spherical bearing), etc...at the front.

Bonus number two. When used in a solid axle application, the spring plates natural resistance to twist acts as an anti-roll bar. Uses some of the same principals as the De-Dion axle.

The OEM looking VW stuff:


And a purpose built version - not to scale. The axle is on the left and the attachment to the frame is on the right. The gray bars are spring steel.

 

i saw the original , '59 Bocar X1 , ( the other cobra , cheeta type racecar ) is uses the whole rear susp. out of a bug , but , only as the lower links . it has 2 bars coming off the axle to make it into a short 4bar setup . must have workt good tough , is was very succesfull . i think that setup would be to wide for a fenderless hot rod

 

This is also an untraditional way, Volvo PV 544 used this set up during the 60´s. A mild splitted "wishbone" attached to the rearend with rubberbushings and a U-bolt. Then the pinjon house is attached to the body and finally a panhardbar is there for sideway movement.
Simple,safe and ugly. Volvo even competed succesfully in rally with this car model. I can´t help it, but i would prefer to copy the old ideas, with all its bending and breaking. Now i´m runnin K-link on my 8 inch, don´t tell anyone...