Technical Split-beam Front Axle - Am I nuts?

First off it's a truck!!!!
Your truck only could be in alignment if it was at a certain weight and a set amount of spring rate and height and break in wear.

Soooooooo
Does a guy bring in his truck with payload weight to get his alignment and drive empty out of alignment?.. Or does he come in empty and drive out of alignment when loaded?,,,
Or when the truck is stopping and has front weight transfer, is it then set up for alignment or only driving normal but must stop out of alignment.

Anyone who's ever owned any vehicle with springs has seen them settle. Should it be aligned with new springs? How about driving around out of alignment for A year then getting the axles bent to alignment, but do you choose empty, some percent of payload, regular driving or some percentage of weight transfer from stopping.

These things are only in alignment for Five minutes if and only if the planets are lined up and ALL road conditions are exactly the same as those on the rack.
Great system when static, but under dynamic conditions it is sort of worthhless.


You said yourself proper alignment only achieved with normal load weight.
delivery trucks change weight at each stop
Grandpas truck can see a weight change at any minute
The work truck might just stay loaded with tools
One driver but on weekends there's three in the cab and camping gear

 

Ford dropped the twin beam after rollover crashes due to bad Firestone tires but it was also shown that axles increased vehicle height in evasive maneuvers making them more prone to roll over.

 

Wow how did I ever survive driving 80's ford trucks?
The twin I beam and TTB 4x4 suspension works quite well and is tough as nails. Hundreds of Baja trophy trucks ran the suspension, even non fords.
The biggest problem experienced with them is the short radius arm. The 4x4 aftermarket sells lots of extended radius arms to lessen the bind on the bushings. When the radius arm bushings go out you wear tires.
A long hair pin with bushings at the axle end and a heim at the frame will work great. Just remember the axle and radius arm form a triangle, the size of that triangle will alter the suspension geometry.

 

Twin I beams have a camber change and toe change through suspension travel. Over miles springs settle changing ride height and alignment. A local GM dealer decided to do a pre delivery alignment on new cars a higher % of those cars came back with tire wear complaints GM must have figured early spring settle in.

 

As others have pointed out the Peugeot is an independent front suspension that uses a transverse leaf spring for control arms. This setup has certain limitations of suspension travel, rearward compliance and geometry but worked fairly well for its time, which was the 1940s. Willys and Studebaker used similar setups. Corvette did basically the same thing in the rear, using the leaf spring as part of the IRS.

By today's standards, could best be described as 'adequate'. I don't know what kind of V12 or how fast you want to go. For a boulevard cruiser with a Lincoln Zephyr flathead it might be ok. I think the Studebaker might be heavier than the Willys.

The Bellamy or Allard is more or less a nightmare. It was an effort to fake up some kind of IFS for Fords when they were 15 or 20 years behind the times with their beam axle . It was cheap and easy to make but didn't work very well. I call it a flailing arm suspension.

The Ford twin I beam worked fairly well although not as well as a proper IFS. It would be good if you were using a very heavy V12 and wanted something that could take a pounding on rough roads.

I get the impression you want the looks of a beam axle transverse leaf front suspension with better manners if possible. In that case it might be well to look at a beam axle with 4 link and coil springs or torsion bars. Jeep Cherokee had such a suspension. Or, of all the ones discussed, the Ford twin I beam might work the best if you want an I beam style.

 

Yeah. They ARE goofy. Wondered if one of those would show up.... Back when I was a kid, I swapped a Corvair ifs into my '2wd Jeep wagon... MUCH better!

 

I was speaking about what load a truck normally carrys. Weight affects chassis angle so if a truck is normally used for hauling weight and is aligned empty, chassis angle will change drastically when loaded and the alignment will be incorrect and cause unnecessary tire wear. The guy that owns a truck that hardly ever carrys a load (like most private owners) would need to align it to what he usually drives ie. empty. On a truck used for constant delivery, it needs to be aligned at it's average load weight. It may be empty by the end of the day or reloaded several times. No matter what, a truck with I beam or twin I beam is best aligned while carrying it normal load. Argue if you like, but I did front end alignment for lots of years and we had almost all of local trucking deliveryman bring their vehicles into us because their tires got longer life when we aligned them. An alignment chart will bear this out, showing how alignment is affected by weight load. Alignment does change over different road conditions. All suspension does. Unless you drive in California where we have the dubious honor of driving on roads made up of various sized interconnected pot holes, suspension flex is at a minimum.

 

Not arguing, I’m agreeing

But let’s pin it down because you can not have it both ways and be right.

The truck with twin beam will be aligned correctly only when it’s in the exact same circumstances as it was when on the rack. The rest of the time it’s not and eating tires. The more changes the more it eats them. Drive 10 miles empty grab a payload and drive 10 miles bringing it back,,, 50% of that was out of alignment. How far out - well how much load.

Or are you suggesting to align the thing with average weight loads, 1/2 way between full and empty? That way the only time it’s in alignment is when it’s 1/2 full. Again every other condition is eating tire especially empty and especially full - just not as bad

 

The Flemke was a solid axle with a "split" buggy spring

 

Imo it'll be ok on your application. It's not like you're likely to have a ton of wheel travel in a hot rod. All the guys beating up on the twin i beam seem to forget they ran it for 20 odd years so if they were so dangerous etc I'm sure Ford eould have been long since bankrupt. Seems like they sold a ton of pickups during that period too. Just sayin'

 

SPLIT-BEAM FRONT AXLE - AM I NUTS?
Simple answer is yes!

 

Debuted in 1965. Left the half ton market after 1996. But it's such a poor and dangerous design that the 2019 Super Duty 2WD still leaves the factory with it. Properly maintained it's not an issue. Eating tires is the result of poor maintenance and/or over loading.

The longer the arm the less significant the alignment change.

 

The design does have more camber change and can have toe changes, depending on how steering is set up. Also can have caster issues if the radius rods are shorter. Longer is better for them. If you want it for novelty, I am sure you can get it to work with an acceptable ride. Just be cautious of the geometry changes during suspension movement up and down. I just don't think you can beat the strength and simplicity of the solid axle though.

 

You can't
and since it's a package deal you can't beat the good looking aspects of it either nor its versatility.

 

Interesting point on the height change during evasive maneuvers, I hadn't considered that, but I could see it, especially if it had a high spring rate...

I think I'm starting to see a common thread here... split beam on trucks.

Rusty, you got it right! Problem is, I can't wrap my head around how to get a solid axle to work with torsion bars. Seems like I would need an additional a-arm or pivot point..

This is interesting! I don't see a benefit over a single spring though. Seems like it would be MORE prone to body roll.

That's the conclusion I'm coming to.

 

Rusty, you got it right! Problem is, I can't wrap my head around how to get a solid axle to work with torsion bars. Seems like I would need an additional a-arm or pivot point.

Here's how Frank Kurtis did it on his legendary race cars and sports cars. Notice the trailing arms, crossed torsion bars and reaction point links.
Coils would be easier, torsion bars cleaner looking. It might be better in your case to have the torsion bars parallel to the frame with control arms parallel to the axle.

 

Here's another idea called Indy-Pendent
https://www.hotrod.com/articles/1002sr-indy-inspired-suspension/

 

I've been following and taking it all in. "Nut's ?" you ask, no. Yes time has ruled out what works and doesn't. But why let that or anyone stop you. I for one enjoy seeing different or out of the norm builds that challenge other builds in complex engineering.

 

That’s VW ish.

 

There’s another where the torsion bars run in the frame rails front to rear.

 

"That's VWish"

Tex Smith used a VW torsion bar front end on his AMBR winning XR-6 roadster. It only had a slant six engine, if you wanted something heavier for a V12 powered rod the VW bus 1979 and earlier had the same suspension in heavy duty form.

 

Deucemac is absolutely correct, I've been doing front end work, alignments since 1980, learned from a man who started in the 50`s

Ford twin ibeams are definitely weight sensitive. And shocks do make a big difference on that design. It's a game of finding a happy medium on weight and ride height.

Simply put it was a bad design 40 yrs ago and still a bad design. The only reason ford used it so long was it was a cheap design to build and manufacture.

There's a reason no other auto manufacturer picked up the design to use unlike upper/ lower control arms, straight axles etc. That alone speaks volumes...

 

It was done so you can run two different spring rates with a buggy spring. Notice how the right side springs have more leaves.

Also, the spring rates could be changed more easily side to side then with a single buggy spring.

 

I seem to recall a split dropped I beam axle advertised in Street Rodder, 2-3 decades ago. Similar to the Fat Man setup but it was Stainless IIRC. Anyone recall it?

 

I do, IIRC it was IFS with the axle being lower A arm and spring the top. Don't remember details

 

Yup, Ford found a cheap bad design and the ad people made it salable for more years than it deserved.

 

I put a million miles on twin I beams loaded and unloaded. No issues or bad tire wear.
I don’t think the OP is nuts. The ford style spring towers or coil overs would look unsightly in my worthless opinion
The transverse spring like the Willys set up looks cool
I agree with others the Henry straight axle is hard to beat

 

Parallel torsion bars could be used with Mopar type sockets, or later GM 4wd. The beams would have to be short or long though, if they were to run along the sides of the oil pan.

 

The only vw-ish thing on Frank Kurtis's front suspension, are the trailing links, which are actually just backwards from "normal" 4-bars. Still a solid axle, in this case a true "straight axle". What it gets you is the axle arc "cup" is facing forward rather than backwards on normal 4-bars. So you get to pay attention to the arc-swing of the draglink (steering box better be in front of the axle, draglink better be parallel & same length as radius rods), & see how it affects toe-in, camber, castor,& bumpsteer under "loads". . Another similar setup to the 'Indy-Pendent' uses 1 solid torsion bar in place of the 2, like a FED &/or acvwVolksRod(Kent Fuller, Tom Medley, Andy Brizio, etc) just heavier-duty. Lots of ways to skin the cat...

Ford has(had) an internal design problem: NIH = Not Invented Here, in which they won't use something someone else invented if they had to pay royalties on it. So it got stolen/litigated-to-death, or circle-engineered-'till-it's-unrecognizable. Unless they happened to figure it something 1st. Does seem to be changing somewhat. Yaya, the others aren't much better...

~'90 Jeep Comanche used a similar front-4-link (iirc) setup on it's 4x4 front w/coils,
~'90 (iirc) Ford Ranger used parallel torsion bars on it's 4x4 front.
Both somewhat compact n easy to find/get parts for.
Marcus...

 

The Bellamy, Allard, and a couple of others cut and welded standard ford axles. They were reasonably successful in off road "trials" racing in the UK. Think rough terrain and mud.
Garpo