Technical Split-beam Front Axle - Am I nuts?

A while ago, I drew up plans to cut a 4" dropped Ford I-Beam axle and add offset tubes, that went all the way to the other side of the frame. Using the longest available 'bones, the camber change would be minimal, over the short suspension travel.

With a transverse leaf, there would be no outward sign that it is installed.

I might do it, on my mid-engine Model A.

 

My FIL and I campaign an 89 Ford Ranger in the 24 Hours of Lemons series, which has twin-I beams in the front. It steers like shit, but it was his idea. That being said, it steers better than a solid axle in my opinion.

 

Quite a lot of 30s-50s modified cars and "Specials" in the UK had Ballamy IFS usually using the small Ford E93A or Brit built Ford V8 beam. I have an OT 30s car with a pre war Ballamy IFS installed. The key to making them work really well is to have the pivot point as low as possible - the space between the two pivots is the roll centre of the front suspension -also having the lowest possible pivot point gives the least camber change as against suspension movement. The photo of the Lotus 11 in post 28 shows the pivot is right at the bottom of the chassis, the Lotus 6 had a similar setup. Mallock Clubman racing cars used one of these swing axle setups on their clubman sports racing cars some way into the 60s -they regularly beat other cars that had wishbone front suspension, so swing axles can be made to work. But an extremely low pivot point would certainly be an issue for a road car in terms of ground clearance.

 

The John Timmanus sports racer was quite successful in the 50s early 60s road racing. It was originally a Lotus 11 which James Dean had ordered but was killed before he could take delivery of. Not sure how he overcame the camber issues of the twin I beam but in this shot it appears he had it figured out.

 

Appreciate all the input, positive and otherwise.

@Stueeee - interesting point about the roll center location; something to consider...
@Rusty O'Toole - Thanks for the torsion bar points! Might revisit that as a front-runner. I do like how much it cleans up the front end if done right, which is important. I'll be running fenders, but that doesn't mean I want to have to hide a mess up under there!

 

Heavy sway bar, the trick is to keep the suspension as level as possible going thru turns. Limit the suspension travel and you can get away with certain things.

That's why it's a working possibility on a race car, not much suspension travel and low mileage use of tires.

 

Hair pins and a solid axle is a pretty good heavy sway bar

 

I would forget about the twin I beam or split I beam axle. Too much complexity for no benefit.
First choice, IFS. If you don't like that choice, use a straight axle. If you want it to have the best ride and handling use some kind of 4 link to control it, and coil or torsion bar springs. Second choice, parallel leafs. Third choice, transverse leaf spring.

 

That’s pretty sage advice right there

Once the argument of ride height vs ride quality is settled ,,,
once you have settled on the amount of suspension travel needed or tolerance of it,,,
Once you’ve decided that the design mantra of form follows function is good or BS

Then pic your poison

 

Split axle on Hollywood Hot Rods Mulholland speedster.

 

Whenever this comes up, a couple of things get mixed up and confused with eachother.

Bumpsteer.
Swingarm suspension has nothing to do with bumpsteer.
My Mallock U2 has no bumpsteer, and my '03 Superduty has it under control enough that the rear tires wear a lot quicker than the fronts.

Camber control.
Depending on springrates, a long swingarm on a racecar can be really effective.
Arthur Mallock and Max Mosely both drove Formula2 Mallock U2 Mk6's , in the mid to late '60s, and they did very well.
Even in combined F2 & F1 races.
( and no, your modern streetrod is not going to outcorner a mid '60s formula racecar )
And BTW, A arm suspensions are still calculated in swingarm lengths.

Not trad.
Yes it is.
Bellamy has already been mentioned before.


In other words...

Just because it has been done wrong many times in the past, isn't proof it cant work if its done right.

 

Action pic of my U2 Mk6 on the limit.

Camber angles are pretty close to ideal, on all 4 corners...

 

Everyone keeps talking about the camber change on twin I beam... It isn't any more dramatic than on unequal length control arms.

 

Nor is the caster change on loaded vs empty, and unless you put the load clear in the rear, the ride height change in the front is not as drastic as some would like to believe.

 

There are those who may argue that point, but it can be delt with.

 

That is a famous and very successful Mk6 Lotus.

The positive camber is because the swingarms were too short, and the pivot points too high.
Which gave a roll center that was too high, and that gave the jacking effect.

Exactly like Bellamy patented it, and later massively improved on by people like Arthur Mallock .

Even Chapman's own Eleven was a lot better than that, with lower pivot points, but still not as good as it could have been with longer swingams.

Again, just because there are some early versions out there that could have been improved upon, doesn't mean the system itself doesn't work.

If that kind of thinking was valid, double A arm front suspensions would never have been tried again after the Lister Jaguars...

 

It's not the caster change it's the camber change, and indeed the camber change is more dramatic on twin ibeams vs. Control arms.

Take two exact vehicles, 1 with twins, 1 with standard control arms in a average street driven vehicle, now take camber reading with both vehicles, now load the front 1" . The ibeam will have a greater camber variance not only from static height but also side to side.

And that 1" inch load change ? It's easily achieved just by the weight of and number of passengers in the front seats.

Again run twin beams but stiffen springs rates, heavier shocks, bigger sway bars and you help alleviate problems with STREET DRIVEN ibeam design. But at the cost of ride.

People keep mentioning race cars and that's fine but who wants to drive a stiff suspension car thru the average city streets ? I sure don't.

 

The racecars absolutely belong in this discussion to illustrate that in competition, where all out cornering performance is vital, a well designed swing arm setup can hold its own.

As far as springrates and street driven cars, my '03 250 Superduty has a softer ride than my '28 Roadster with its I-beam...

 

The picture of the split I beam, with quarter eliptic springs looks better than Ford's ugly coils, on their trucks. Torsion bars probably could make it even more appealing, in the looks department.
I have own 2 twin I beam trucks, and never had tire wear issues on the front. And handling was more than acceptable. I drove them empty and overloaded too. So yes, weight at the time of alignment is a factor, but some middle ground must have been settled upon, otherwise, all of them would be out of alignment, almost all of the time. And with no real issues with tire wear, they must have picked the right number, when it was set up.
I have seen a Willy's front end in the junkyard. It looked interesting to say the least. I do have to wonder about the spring twisting from front to back though. If something had slop in it, I think it would become a problem.
But if you are going to use a V12, then perhaps you should consider an I beam with springs on both sides. I recall International advertising it was used to spread the load over more points of suspension, on the frame.
Good luck!

 

Dominator Street Rods has a similar front clip available. Gary

 

Do a search for Lee Osborne and Steve "The Greek" Panarites....they do a ton of the torsion bar suspension chassis with great success.

Sent from my SM-G950U using The H.A.M.B. mobile app

 

We are getting off topic... but I just got a frame from Steve. Only TB in the front. Back is still TBD. Gary

 

This is the car I was referring to on page one.

 

So to get back to your original question...

No, I don't think you are nuts.

A Swingarm IFS has lots of potential.

It has its drawbacks and strengths, but it can be made to preform very well if designed and dialed in right.
Even compared to systems that, at first glance, look to be superior.
Same could be said about something like a McPherson Strut, and those are everywhere.
(but for some reason, not nearly as many old wifes' tales are told about those...)

It would take some determination, because it looks like there are no off the shelf setups that are suitable, but the right guy with the right skills can do it.

 

When I say the McPherson is a OK design with it's limits that are reached quickly even mechanics look at me funny, usually their answer is : why do you think they're everywhere?
Me : because they're cheap with ok results.
Then they argue.

 

this has to be the "safest" post I have ever seen...

came across this thread as I was day dreaming about my post T project, a 50's hot rod of course...cause Allards are just hotrodded Fords

 

agree with mr. Palmer on the Flemke front axle. Was one piece... with two springs and two jack bolts..... was the hot deal in modifieds for a long, long time, where ever they raced. Never saw a twin -I -beam on a circle track car in the northeast, but I'm guessing it was probably tried at some point. What I have seen is a tube axle cut at center, with a slug inserted into both haves to free up the front end regardless of suspension type, I'm thinking some thought and time went into getting it all to work right, and as usual to survive the rough and tumble of short track racing. Sorry to veer off course on the twin- I deal.

 

I'm lookin at this again and really like that setup!

 

Here are pictures of a road race '34 Ford from Argentina from January 1959 Hot Rod Magazine.

 

My father-in-law farmed his whole life. He once told me "he wouldn't ALLOW anything other than a Ford truck on the hill" ......until they went to the split I-beam front suspension!! Shivel-layz from then after. He later said he had forgotten how good a truck could ride until he switched from the split I-beam Ford to the Chevy!
Don't think he was the only "Ford-Man" to switch over to the "dark side"!
6sally6