Technical I-beam IFS and Banjo Transaxle

The front on my '72 F-100 has a split I -beam and it handles pretty well? I was just looking at an Allard yesterday and dreaming of building something similar! Do it!

 

I agree with volvobrynk. If you want IRS or a swing axle, then go for it. Why would you want to tie the hubs together so that it reacts the same as a standard live axle? What's the advantage for your dream setup?

 

The DeDion can be configured several different ways. It can be above or below the gearbox or even ladder style with 2 smaller tubes, one above-one below.

 

It could be done a lot like this


IRS being the best of them


With careful cutting and grinding, that could be connected Transporter transaxle, with a torque tube between trans axles and engine, clutch cold be front or back.


But running it with small shaft like the upper De-dion, it could be made to look age appropriate. More Miller-Indy-car-like

 

Mercedes Grand Prix cars of the late '30s had DeDion axles, quite a clever arrangement located by a pin sliding in a groove in the back of the differential housing. Thereafter they began trying to make swing-axles work, like everyone else in the German-speaking world. Why, only they will know. Thus the first 300SLs had that lethal set-up. After experimenting with compensator springs they went to the first of the low-pivot swing-axle systems, which was a somewhat happier compromise. I think the main consideration was cost with an eye to use on regular production models, as the system needed only one CV joint. It was the Mercedes standard throughout the '60s, until the W114/115's semi-trailing arm system.

I'm not sure where the semi-trailing arm set-up began. The earliest one I can think of is the BMW 1500 of 1962. It was a vast improvement on the swing-axle, but it still had its foibles. It wasn't really prone to jacking but it would still go to rear toe-out if you were to hit the brakes in a corner, with tricky results. I must say I never had any trouble with my BMW 2002 - which had the exact same 1962 system.

More a bit later.

 

I was not only trying to keep the front end pleasing to the eye, but use leaf springs as they are period correct and keep the front end simple and uncluttered. That availability for the volvo box may be a little too scarce for what I'd be able to find at an affordable price. Hewland would be nice, but again price and availability come into consideration. Also, there are space concerns (see below).

Yeah 928 transaxles are getting up there and are the only one of the group that, besides being rear diff., would be able to handle any decent amount of hp (what I was able to find anyway). The alpha setup is a very alluring setup, as the whole package is already assembled. However, ability to withstand hp is still a concern (albeit more than a 924) and ability and price would not be very favorable. I also agree that a good solid front axle is better than a bad ifs, which is why I'm trying to get the wrinkles ironed out with everyones' assistance.

The beetle IRS is pretty decent (I own a beetle myself) though it is definitely not period as it started in the late 60's. Further, I do not know of any autos that had semi-trailing arm suspension earlier than that decade, which would rule it out as period (please correct me if I am misinformed). The vw swing axles definitely had there problems with the inherently high roll center and large camber and toe change throughout their movement. The Mercedes 300SL/gullwing had a triple sprung (coil for each wheel and one compensator that connected the two) swing axle as far as I know or can find. Due to the high roll center inherent to the swing-arm IRS, jacking occurs on hard cornering, which can lead to rolls as in the Mercedes' case. The DeDion axle is a very stable setup.

The F-100s are slightly different in that the pivot is relatively high on the chassis, which doesn't serve to aid against jacking with the already high CG. However, the swing arm is long, which is preferable. Allards are pretty awesome little cars, though the shortness of the swing arm and high pivot lent themselves to some rather odd handling characteristics. This can be somewhat remedied by lowering the pivot point as done on some rather common modifications.

Whether or not it is on this ride, I do plan on building something with swing arm IFS at some point for laughs if anything.

With the hubs connected, camber is kept constant regardless of cornering conditions (leagues better than jacking from swing-axles). Where it holds an advantage over a live axle is a substantial reduction in unsprung weight.

The IRS is definitely the better of the VW suspension setups and could probably be easily adapted for a DeDion rear. However, the VW transaxles are definitely not strong enough to hold up to much power without substantial and costly upgrades.

This is true and definitely something to be considered. The reason I had planned to have the DeDion tube behind the rear diff is due to clearance concerns whether it be between the body and transaxle or the ground and transaxle. I also do not want to reduce the travel to some small distance that would only befit a track car. This will be a driver after all. If you think it could work, shoot me some ideas.

I like your clarity and depth of your explanations! That low-pivot swing axle is something else too. Kinda pretty and would look right at home! That would definitely be an alternative to consider to the DeDion. It is also similar to what I was thinking of doing in the front (minus the drivetrain and pivots moved to opposite sides of the chassis.)

Don't get me wrong, I like semi-trailing arm IRS and it definitely has it's place. I think it would be an odd looking thing with anything other than coil spring, however, which just doesn't sit with me as 'period'. Believe me, I've thought about it. I have even thought about leading or semi-leading arm IFS as a quirky and different approach to IFS but have found almost no commercial success in that regard while researching, exempting the roll crazy 2CV. Alas, I digress.

 

Here are a couple of pics of my Mallock U2 Mk6.
( which was the last type with the swing axle front suspension, the Mk7 has double a arms,
and BTW, was not as quick as a Mk6 )
The IFS front suspension is built out of the I beam from a Ford Pop/Anglia, cut in the middle, and then both pieces were lengthened so the pivot point for the RHS is on the left, and the LHS is on the right.
Kinda like a Ford Twin Ibeam, but with carefully developed geometry ( lengths of the swinaxles, height of the pivot points, and placement of the R & P so there is no bumpsteer, etc ), as well as the right spring rates & shocks.
In the pics you can see there is absolutely no trace of the outside wheel trying to tuck under like early Allards and others with the same kind of suspension used to do.
It handles like a typical single seater of the period ( mid '60s ), which is pretty damn good...

 

Here is one more pic where you can see the front suspension a little better.

 

Another car you should check out is the Lycoming Special from New Zealand.
Because it has a lot of things you are talking about.
It has a home built transaxle made out of a Studebaker gearbox and a early Ford V8 diff, and a DeDion using Jag parts.

http://classicdriver.co.nz/the-lycoming/

 

Here is the later, single-CV Mercedes Benz low-pivot swing axle:

The final drive tilts with the left-hand axle, so it's not much use with a transaxle.

The great advantage of solid axles is that they maintain constant camber under all conditions except single-wheel bump. To a large extent the history of high-performance independent suspension has been that of attempts to get it to behave like an axle, without the shortcomings of an axle. You could say that a DeDion axle is the better part of the way there. And a lot of the early appeal was the ease with which ifs could be got to make the front end grip as badly as the rear, which isn't as crazy as it sounds.

By the way, the 2CV's extreme roll angles come more from the famous umbrella-on-wheels/basket-of-eggs/ploughed-field brief than from the suspension's geometry. 2CV racers cut and thereby stiffen the springs drastically, resulting in much greater roll stiffness:

The leading/trailing-arm suspension still gives camber gain equal to the roll angle, which isn't ideal.

 

Yup. I posted a How-To article from hot rod in 1954 a while back.

 

http://www.jalopyjournal.com/forum/...ditional-swing-axles-for-your-hot-rod.998930/

 

Granville Grenfell unfortunately didn't have a patent in the USA for his overlap suspension for when Ford 'borrowed' it....

 

I'm guessing Rene Panhard and Jules Albert DeDion didnt get paid either...

 

Your car is part of the inspiration I had for my ideas. Of course, I contemplated the use of parallel leafs as the beam locator and spring. Question: what is the travel on your suspension? I'd assume it isn't much given the ground clearance and intended purpose of the auto.

The car looks like a blast!

That car looks awesome! The rear is almost exactly what I had in mind for the rear end! The use of the lycoming is also very unique.

That is indeed my reasoning behind the DeDion, along with the period feel and performance gains. On another note, I had no idea they race 2cv's! It must be a sight to behold and experience.

Yup! I have seen it before and it is truly an interesting read. I might consider a similar build in the future if possible.

 

Yeah, the springs are pretty stiff. ( not that much suspension travel)
But it doesn't feel any more harsh than my '28.
I think that type of front suspension would work really well on a Hot Rod.
And a DeDion as well.

I had one of those on a racecar I built out of what was left of an old Sports 2000 Lola.
( see pic.
The DeDion was a separate spaceframe that wrapped around the engine & gearbox, and it was adjustable for camber, toe in/out, roll center, and the front pivot point was adjustable for height as well )

 

Some of the inherent problems that the twin-I-beam Ford suspension design has is in the steering arrangement. The drag link is connected from the steering box to the right spindle and the connecting tie rod for the left wheel is attached to a point that is inline with the left axle pivot. A better way to go would be to use a center link with an idler arm and then attach the left tie rod to the right side inline with the left axle pivot and the right side inline with the right pivot. The hard part is getting them to cross without interfering with each other. This can be accomplished with careful bending of the tie rods.

My dad and I used a 65 Ford truck with twin-I-beam to build his car on. We cut and dropped the frame in the middle so that essentially it would be the same as having the back of the frame on the ground. This gave it more king pin angle and it would corner quite well with the low CG and wide track along with the geometry change.

For the rear design I have thought of using torque tube ends inboard and out board use the ball and knuckle from a Willys 4 wheel drive. To do this you would need to rotate the steering knuckles 90 degrees so that the trunion bearings are horizontal to the ground. You could then use the steering arm as an upper or lower link dependent on which way you wanted to go. To control the fore and aft movement and rotation of the outer knuckle you could use a rear bone off of an early Ford rear as it is not taking the torque of the rear but just the longitudinal force.

This set up would give you a full floating design on the hub so that if an axle or half shaft broke you would not lose a wheel or suspension. The disadvantage is that it makes it hard to have inboard brakes. This can be overcome as well by using the brake design that a lot of tractors use and was used on Chrysler limos in the 50's.
https://en.wikipedia.org/wiki/Ausco_Lambert_disc_brake
http://www.bing.com/images/search?q...5bfb830e9b1074b2901b2de33b6ec65eo0&ajaxhist=0

 

Inboard brakes are enticing but often not very successful, they are right next to a hot diff where it is difficult to get cooling air. Also there are problems of service and repair. Outboard brakes are more practical.

 

That's actually quite surprising that the ride difference between those two is not terribly great. Another point for the split I-beam setup! I've seen a post you made on that setup before and it is insane. I see that the woblink can be adjusted with the lengthening/shortening of the two arms and the mount on the DeDion can be raised/lowered with the various attachment points, but where do the other adjustments come into play?

I was thinking of avoiding that linkage problem all together and using two separate drag links for each wheel with rockers and a tie rod farther towards the rear like the Foose P-32 used or using two pitman arms and two drag links like some early indy cars had. The center idler arm would also have its issues with suspension travels, as the two tie rods would be shorter than the length of the swing axle, effectively 'toeing-in' the wheels with suspension movement. However, it is definitely better than a single tie rod.

That IRS design is very interesting and quite possibly may work. The only issue I could see is the angle built into the 'king pin' which originally would change camber with the turn of the wheel would now (I think) change toe angle with vertical suspension movement. That brake design is also something else! Quite interesting to be sure, but they seem to have been abandoned only a few years after their introduction to production. I can imagine parts would be a bare to source.

Yup, I've thought of that. I figure I'd be under the car anyway so it wouldn't be much different. I also was thinking of running cooling ducts anyway.

 

I was going to suggest the double drag link but forgot. I plan on using Fordson tractor steering in one of my hotrod projects. With the limited travel on the suspension I would think that the trunion angle would be negligible and you could make your bone mount inline with it so there is no binding.

The lambert brakes were expensive to produce and were a bit sensitive due to the ball ramps being too long and creating too much leverage. The ones used on tractors have shorter ramps and the disc spins instead of the outer housing.

 

A couple of my friends recently bought several cars out of Houston, two of which were '22 Chevies. One was a touring, the other a depot hack, and both have dual quarter-elliptic springs at each end. The front axles are typical I-beam types and the rearends are typical banjo-style. No independent design, but this was 1922. I guess quarter-elliptics just didn't catch on.

 

Quarter-elliptics were a perennial part of the cyclecar technological toolbox, famously surviving on things like Frazer-Nashes and HRGs. A few others used them over the years, too: the definitive Bugatti rear suspension featured back-to-front quarter-elliptics, presumably to give a tad of roll countersteer. Later, some Jaguars had cantilever semi-elliptics at the back.

 

About the steering:
My Mallock uses cut wishbones ( the ones that came with the Anglia/Popular axle ) , just like a trad Hot Rod setup.
And the lengths are chosen so that when you draw a line between its pivot point and the pivot point of that half of the axle , and then do the same for the other side, the lines intersect behind the axles.
On the centerline of the car.
So that point is where the center pivot points are for the steering.
( Rack & Pinion in the Mallock)

No bumpsteer...

For the Camber & Toe adjustment on the little single seater, I made sort of a upright that bolted to the DeDion cage.
The attachment points were in a L shape at a 90 deg angle, with the outside ones slotted.
So by loosening two of the bolts I could adjust one without changing the other.
You can see the two bolts for camber adjustment in this pic ( the top one is slotted )

 

That rear suspension was part of my learning curve, and I wanted all the adjustability I could get.
Turned out that once the toe and camber were set, there was no reason to change it.
So if I was going to do it again, I'd just build a regular beam, like most deDion's are.

I really do believe in the DeDion rear suspension.
That car was super short, with a very low polar moment of inertia ( the weight concentrated near the center ) so it was a tricky car to drive.
But I'm sure the DeDion calmed it down, somewhat.
And in outright cornering force it was a match for late '70s Lola Factory front suspension.

 

I had the water tank out and thought you might like to see a picture of a rear end built 40 years ago to the Hop Up story. Note this car has seen plenty of passes in the last 40 years and is not rusting into a heap like so many say

 

WWWWWWWOOOOOOOOOOWWWWWW. Thanx, Gary

 

Almost forgot... I was planning on posting this earlier but forgot until this thread came up again. On a recent trip to the bay area I stopped by Dominator Street Rods to look at their dual axle IFS for street rods. I don't know how it relates exactly to the Ford dual I beam design, but I liked it. It just has to be better than splitting a straight axle in the center, eh? I believe it's also sold thru Flaming River. Down side for me, it that it was designed for use with coil overs. Ifn I used one, I'd somehow figure out how to get torsion bars on it. From where the display was located in the office and my non-wide angle lens, I couldn't get very good pix so I can't speak to just how the dual tube axles are mounted / work ICW each other / keep the spindles in the same plane(s), but it's a very nice looking rig. I didn't ask about the cost, either. But I did take pix! Gary

 

Actually there has been some talk of rebuilding the roadster to accommodate some real horsepower. Which requires a new frame and rear end. So if that happened this one would be for sale. V8 quickchange, spool, '56 Olds halfshafts and brakes. Cross torsion bars. Many gear sets. If you are interested PM me. Wouldn't happen for a few months if at all.

 

Anyone have more to share? Gary

 

I had a thought today. If one shortcoming of the semi-trailing arm system is that it reaches its maximum toe-in somewhere around ride height and goes to increasing toe-out as it departs from that, why has no-one tried to turn it back-to-front? That would be semi-leading-arm rear suspension, and it would tend to increase toe-in with suspension travel.

Porsche started the whole multi-link business (which is more often than not a desperate attempt to get a semi-trailing arm suspension to be better than a 90% solution by throwing complexity at it) with their Weissach Axle. I wonder if anyone at Weissach thought of simply running it backwards?

An incidental benefit would be improved launch behaviour, as packaging constraints prevent putting the arm pivots high enough for geometry conducive to hard launching if the pivots are ahead of the axle, unless the rear tyres are very short. Tall tyres and low pivots behind the axle would instead be good for hard launching.