Technical Why Are Tube Front Axles So Common on T's?

I don’t have any kind of fact based answer but they sure do work well.

 

I think it was to emulate the V8 60 look of Ivo's and the Kookie cars on a cheaper more readily available basis. On a side note you can use conical washers on each side of the rear heim joint on the hairpin to get more articulation.

 

A lot of the early near-Fad & early Fad 'T's, mid 60's -> had the sort-of appearance & emulation of the Fuel Altereds of the day. So the large slicks, rearend pushed forward, & tube axles + real mag wheels (often as not = spindle mounts) or motorcycle wheels, like they used. Somehow it wouldn't surprise me to find out that a lot of the chromed tube axles were from the race cars in CA.
Marcus...

 

Damn thing is smiling at me. LOL

 

Great looking car!

 

This is in a scanned T-Bucket building book I obtained a long time ago. It's a scan of a printout with hand written notes and multiple holes visible from a 3 ring binder. It shows how to make a tube axle, frame, hairpins, & brackets (with patterns) in your shop with mostly simple tools, a roll of tape, and a couple boards. It does suggest a mandrel bender for the axle though.

It shows how to mount a Jag rear end so that probably dates it.

 

I almost built a dropped tube axle once. Then I priced them. Unless the axle needs to be custom, an off the shelf unit is cheaper if your time is valuable.

 

Tube axle with split bones makes one hell of a sway bar.

 

I never thought of it that way. My plan is custom bones on a tube axle. My son is planning hairpins on a tube axle. If I could find the right car or body for my ultimate T build, it would be bones on an early I beam.

 

That's not a good thing!

 

I never said it was a good thing adding a massive sway bar will change handling sometimes not in a good way.

 

Sorry you misunderstood. You are correct. My response was actually directed at Loose Ctrl's statement. Bones or Hairpins on a tube axle is not good engineering practice for exactly the reason you stated.

 

So what then, a four bar set up? I know if pins or bones aren't set up right, they will bind and/or cause bump steer really bad. Also, they can pick up death wobble.

When I set up a split wishbone front end, I do them like Ford does their TTB front axle radius rods. I have even used Ranger bushings on one set up where the transmission ends were tucked under the chassis on brackets. It wasn't a really low car.

 

Neither bump steer nor "death wobble" are related to the axle locating method. Bump steer has only to do with the steering box and linkage locations. Death wobble can be caused by any number of issues, but probably not the choice of bones, hairpins or 4 bar.
Imagine rolling slowly through a very lumpy parking lot. Your right front tire is about to roll up on a 6" bump. Your front axle has to articulate. The axle has to twist to allow this motion. The tube axle with split bones won't twist very much, so the left front tire wants to lift off the ground unless your frame or something else flexes enough. (Not good.) An I beam axle will twist enough to allow this motion. A 4 bar puts no twist in the axle at articulation. Bones as Henry made them put no twist in the axle at articulation. So unsplit bones or 4 bar with a tube axle.

 

I get what you're saying. Axle induced chassis flex due to limited axle articulation. That was my reason behind using the Ford radius rod bushings and mounting the ends more under and central. The bones I built were faily long, I believe 38 to 40 inches overall. The chassis ends didn't get much movement with six inches of up and down movement, 12 inches total. The front end seem to swing pretty freely with just the bones and panhard bar attached. Of course the panhard can induce some strange things as it causes the axle to push to the sideas the axle swings past center. I don't think a front panhard is need with a transverse leaf spring. It got one anyway.

 

I would have to say that most of the T buckets out there started out as a kit car and that is what the supplier uses tube axles.

 

If shackles are around 45 degrees on a cross spring a panhard is not needed. If the shackles are at 90 degrees they act like a swing allowing the axle to move side to side not good on a cross steer and a panhard will help.

 

They were not quite 45 but far from 90. They had just the slightest hint of up turn from the spring to the mounts on the side of the bones.

 

37 tube axles "were the way to go "on track roadsters because they acted as a rude antisway bar in the corners . Later ,T bucket hotrods were inspired by front engine dragsters at the time .
America was about " if some is good , more is better !" Including putting the largest engine in the lightest car . Wild looking chromed out T buckets were insane looking next to a 56 whatever grocery getter in traffic !

 

The non v8-60 tube axles were used in the kits because they had next to zero Early Ford content. They were built from scratch with all new parts (except for the drivetrain).

 

Somebody earlier mentioned that it's easier to get a big drop out of a fabricated tube axle. Here it is, taken to the extreme :

 

While technically correct the T chassis under most buckets is a ladder frame , flexes like crazy,.also a T frt end rarely travels more than ,3" total up and down , so binding is , at best ,a negligible problem . You can wax poetic with your " poor engineering" talk , but that's the long and short of it .. My opinions are based on 50,000 miles of driving my T on public roads... And engineering is the accurate recording of what works and what doesn't.....

 

I stand by my statement.

 

This statement has bothered me since I read it. Recording what works and what doesn't is trial and error not engineering. Engineering is an effort to eliminate trial and error. Trial and error is what happens after engineering has failed.

 

How does one " know" what works or doesn't work without trying it , untried=unknown

 

I don't have any science to back this up, only impressions and observations.
My guess is Model A roadster builders are more predisposed to beam axles and Model T builders are less choosy. Maybe it's something to do with a touch more "tradition" factors with Model A's. Sort of like the ol' what kind of haircut to use on certain breed of dog(s).
Of course, there are plenty of crossovers and exceptions. But if I had to slice my own brand of baloney, that's the way it feels most likely to me.

 

I think "kit" T"s come with tube axles because the makers specialize in fabricating steel.Its cheaper to cut 4 feet of tube,and weld one up,and make money doing it than it is to out source a forged axle.They try,and keep kit prices "cheap" to get you to buy.If their pile of parts cost just as much as you collecting your own they would be out of business.Cars always go over budget,but at the outset the kit price looks good enough to pull you....and your wallet in.

 

if something is re-engineered, it's because it was subjected to the trial and error method and failed. If everything was engineered correctly, trial and error wouldn't exist. Without one, there would be no need for the other.
And I used a tube axle on my first T because I wanted a seven inch drop, and an Ibeam couldn't be done in the way I wanted it..

 

2OLD2FAST
and
jaw22w...
You're both right.
It's true that a mechanical design can appear to work on paper, but not so much in reality. But so much engineering has been done in the past, that we rarely have to reinvent the wheel... as they say. So engineering is relying on what we've learned in the past... and recorded... and applying it to new designs.

Mistakes still happen, though. I designed machine tools for 25 years. Every once in awhile, the guys out in the build shop would bring the drawings back into the design shop, lay it down on somebody's drafting board and ask...
What the hell is this?
LOL

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I like I-beam axles.

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