Technical No-bind long ladder bars?

Has anyone ever tried to get the great look of the 1960 era long ladders with a decent suspension action? I am having ideas of a pivot arm across the chassis that pivoted in the center of the car below the rear u-joint. Then have the ladder bar front rod ends bolted to each end of the pivot arm. This could allow the pivot arm to let the ladder bars equalize without bind. Might cause some clearance concerns for working room. Wouldn't it be similar in action to a wishbone configuration?

Another idea it to use regular ladder bars but only connect the lower rear mounts to eliminate the bind, leaving the unbolted mount in place just to preserve the looks. Then add a hidden third link over the top of the pumpkin (adjustable, for bite?) to control axle windup.

BTW, I am considering an alternative like this on a street driven 32 Roadster done in a 1959 A/SR drag racer style with a buggy spring. I like the looks of the wide mounted ladder bars, but want the system to work correctly, be reliable, ride reasonably well, etc.

Any ideas?

 

I meant pivoted under the front u-joint, sorry.

 

Panhard bar would be necessary.

 

I have an 8 inch rear end with wish bone under my 2 door.
The anchor point is directly under the front u-joint. Rides as good as a model A can be expected to. Handles good. I have run it in a couple of backwoods rally's.
No panhard required with cross spring.

 

I don't have a pic but I drove a model t rpu with a stock rear leaf and 4' long ladder bars paralel to the frame rails for over 12 years, this was on an old time hotrod which had been built in the 60s. With the ford leaf you don't need a panhard bar and it also had a set of old motorcycle shocks. Guess I didn't really answer your question but it sure could hook up.

 

I use Pete and Jakes ladder bars on my Roadster. 29 Buggy spring over the axel, Hiem joints in front and Clevises in the rear. Front mounts at the front U joint one on each side of the U joint. Heim joints allow for twist.

 

as long as you aren't using parallel leaf springs you shouldn't have any bind , its the parallel leafs mounting points that created it by making 2 different rotational radiuses , we used a slipper to locate the axle in place and allowed it( axle and ladder bar to rotate and lift the body. we still use this set up today on our short ladder bar car , no diagnal or wishbone needed .

 

Years ago I posted a similar thought, including child like drawings! The problem is, looks good and rides better then normal ladder bar front mounts, BUT it would be very greasy under serious power due to the engine rotational forces and the opposing axle torque. Ladder bars no matter solid shank or heim joints become a hinge that pivots in the bolt area, period. They can not, do not allow one wheel in the rear to rise or fall differently then the other rear wheel. Period. Just the nature of the beast. Want a good ride and traction? Run a 4 link. Ladder bars are caveman traction, but they work! The world is full of tradeoffs.....

 

still tryin to figure out how well these worked?...the front pivot has to be well in front of the front u-joint?

 

As long as you don't go past the U joint bind should not be a problem. I effectivly makes it a truck arm suspension like an early C-10. If you are running leaf springs you have to have floaters at the spring.

 

I'm guessing nose up

 

wouldn't want to be in it if the front bolt snapped and you touched the brake .. ( I know what happens to the cheapie slappers when they do that .and that wasn't pretty . )

 

That's why NHRA requires a safety loop at the front mount on ladder bars. It saves you from pole vaulting your car if the front breaks.

 

Jim Meyers Racing http://www.jimmeyerracing.com/ has a setup that could probably be copied with long bars.

If you dont want to do that style, and just want to avoid bind, mount the forward end of the ladder bar to the TOP end of a spring shackle that anchors to a crossmember below the ladder bar.

The shackle will handle any dual-radius swing binding, and the front of the ladder bar will lift the car by the shackle. Much like the adjustable 3rd link of the 4th gen camaros. -rick

 

Thanks for all the input. There is, of course, no bind with ladder bars when going straight, the bind comes in when the body needs to roll, or when one wheel hits a bump and the other doesn't. It is simple to cure this by making the long bars angle in to the center, but in all the early examples ('59 or so) they are all connected to the side rails, or close to them. This was great for straight line, but not so much for street use where parts got broken, bent, or a wheel lifted off the ground when entering a driveway, for instance!

I am trying to set it where it looks period correct, but works better.

Again, thanks for the input so far!

 

Thanks for all of your input. Of course, the long ladder bars do not bind when going straight. They only bind when the body needs to roll, or when one wheel moved differently than the other. In a drag race situation, the long bars mounted to the frame rails work great. But when used on the street, they bind, break or bend parts, or even lift a wheel off the ground when doing something like entering a driveway on an angle.

Of course, the simple fix is to simply move the front mounting points to the center of the car, but I am after a more authentic 1959 look, where they are all mounted wide.

I want the look of the wide, with an improved street manner. It may be a tradeoff that can't be fixed, but it sure seems like there is a way.

Thanks again for your continued input.

 

Ok, you could use long bars mounted to the top of a spring shackle but attach them to the shackles with a rotating swivel (one for each bar). Rubber bushings in the shackles should take up the sideways action.-rick

 

Putting street car stuff against real race cars makes you second in 2 place race aka looser.

Putting race car stuff on the street that doesn't work like race car stuff but kinda looks like race car stuff makes you something else. Poser maybe?

 

the u bolt on the set is the part that did break ( rusted at the threads ) , when it caught the street it made some noise till it caught a expansion joint then pulled the spring right out of the mount on the chassis . have to say them J bolts are sure strong !

 

69 Fury, I don't think you are understanding what is binding with ladder bars. With two rigid beams attached to the frame, it doesn't matter how it is mounted there, unless the axle twists or the ladder bars do, there will be bind. The only way to reduce this is with 4 bars or a central pivot (i.e. wishbone), as far as I know. If the ladder bars only mount at one point on the rearend and swivel both there and at the front, they become simply lower control arms, while still appearing to be ladder bars. Then if a single or dual upper arms are added (like hidden over the top of the third member, everything pivots correctly without bind.

Though I didn't use long ladder bar looking bars for lower mounts, I did this three link system on a V/8 Volkswagen I built back in the 70's. It bit hard and ran straight. My concern with the 32 is the amount of space necessary to get the correct geometry on the upper link.

And yes, 31 Vicky with a hemi, it is kind of a 'Poser'. a 1959 A/SR would not be very competitive as a racer in original configuration. Like a LOT of the gasers on the board, I want it to look the part, but not actually have to be a real race car. So, is your vicky an all out race car, or a street car? How quick does it run?

Thanks

 

And yes, 31 Vicky with a hemi, it is kind of a 'Poser'. a 1959 A/SR would not be very competitive as a racer in original configuration. Like a LOT of the gasers on the board, I want it to look the part, but not actually have to be a real race car. So, is your vicky an all out race car, or a street car? How quick does it run?


Your A/SR should be competitive in a 1959 vintage class, that's where the fun is anyway.
Most racing today is brackets and you run against yourself and the dial in.

I have no clue how fast it runs, and to tell you the truth I'm a bit scared of it and it Hasn't been fired yet. Lol

So with long bars mounted close to parallel that act as lower control arms and a hidden third link, isn't that going to give the pinion angle hell as the suspension travels? What about your instant center?

 

Truck arms kind of sound like what you are trying to do?

I have also heard it called a "triangulated two link".

Careful, though. If Johnny hears (sees) you call it that, he may light you up pretty good!

 

""Another idea it to use regular ladder bars but only connect the lower rear mounts to eliminate the bind, leaving the unbolted mount in place just to preserve the looks. Then add a hidden third link over the top of the pumpkin (adjustable, for bite?) to control axle windup.""

The above is the OP's second combo and will work fine..Third link does not have to be as long as the "ladders" but should have adjustment for pinion angle and total bar angle for instant center adjustments...Only negative I see is you may get some rattle from ladder unattached upper rear mounts but some rubber spring bushings should [like for a spring eye/shackle] should take care of any noise...

 

Thanks again guys. This isn't my first rodeo, I have built lots of street rods and race cars from scratch. I am well familiar with "truck arms." (I've had a few 67-72 C10's, too, over the years) Truck arms are simply long traction bars that have their ends moved to the center of the truck to lessen the bind. They are purposely built of relatively flimsy channel so that they can twist in action.

I am well aware of the intersecting arcs, instant center computations on the 3 or 4 link systems. With the long traction bars it is more difficult to get the lift point to lie on the line from the contact patch to the center of gravity, but possible.

Of more concern is the change in pinion angle due to the difference of the length of the bars. In this case, after a little measuring, I think that I can lengthen the upper arms and adjust the pickup points on the upper and lower bars to correct the instant center. And given the limited travel available, I feel like I can manage the pinion angle change.

So, at this point, I think that I will design traction bars that look like regular ladder bars, but have only ONE ball joint on the rear. They are, in actuality, a single bar, and if inspected closely will not even appear to have two mounting points at the rear. I will use a wishbone or dual upper links in order to lower them on the housing, clear the driveshaft, and locate the rear laterally if I decide to run longer shackles on the buggy spring. All mounting brackets will have a couple of adjustment holes to adjust for proper bite.

Vicky with a Hemi, I have made more than a few passes in the last 40+ years that I have been racing, so, while I will likely make a few passes in my deuce, I will probably just run my 23 T altered. I have also made a few passes in the twin turboed 355" sbc powered VW Beetle with 95" wheelbase I built in high school back in the early 70's, so I can understand your concerns.

Let me know when you get the Vic to the track, I might line my "poser' up agin' it!

 

Thanks, Seb Fontans, you have it correct, and understand the problems. I have decided against even having an upper mount. The ladder bar will just return to the single spherical rod end behind the wheels. It will sit pretty high, but you would still have to crawl under to detect the skulduggery, I think.

 

Driving "real" ladder bar cars on the street is just a compromise, kind of like a spool on a street car, just more compromise.....

My street car is a 8-71 540 on E85, should make decent power and a Lenco trans, with a spool and S&W 42" gasser ladder bars, and I plan on driving the wheels off of it!

Good luck with the project. See you at the HAMB Drags soon.....

 

What would be wrong with having a slotted floating front attachment for the ladder bars on a leaf spring car instead of using a floating leaf spring mount on the axle?

 

Lobucrod, that is not the problem. If you have two solid bars and then try to lift one wheel, there is no way for it not to bind. One front mount would have to move up while the other moves down. Front to back slotting would not affect that.

 

Also, remember that this is on a cross-leaf arrangement, not parallel leafs.

 

Never had a set of the slapper bars with the U bolts. And real ladder bars don't use them either. Most the slapper bars I owned many decades ago were welded to the spring perch plate, and had a small U bolt that just went over the spring. Even if it fell off the slapper bar was still a long ways from hitting the ground.