Thread: 41 Willys Gasser project

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Originally Posted by Henry Rifle

Not intending to start an argument, but I know that Competition Engineering commonly makes anti-roll bars from 4130 moly tubing, and Hotchkiss has some good design recommendations. Tubular sway bars are common on many factory cars on the road today. Heavy wall 4130 has pretty hairy torsional strength. I agree that tubular is a no-no if there is any bending. However, a properly sized tubular roll bar with the type of links that Steve has shown is definitely usable. Check the following link:
http://www.hotchkis.net/_uploaded_fi...ons162file.pdf

You are correct Jack.

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Originally Posted by roadster32

Roger its quite common place to make anti roll bars in chrome moly tube, I've made them in it for years, it works very well.

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Yeah, Steve, I'm a bit red faced by my comment , especially after Jack posting his info from Hotchkiss. Should have known you'd already done your homework on the material, but it looked "light", and then Jerry's comment.... Sorry for the bother

Thanks for the chart Jack! Been wondering how to figure the rating of a hollow bar vs. solid. Not near as much difference as I figured there would be!

Great work as always, Steve! Hope your cylinder heads arrive soon, waiting eagerly for the maiden blast on the car!!!!!!

Originally Posted by jerry clayton

Steve's tubular anti roll bar will work fine as an anti roll device for acceleration in a straight line---to off set torque roll like on a drag strip --straightline acceleration---

It is not the ideal answer to any chassis roll from a cornering application---If it doesn't break the tube or links , it will tear the mounts loose from the frame member------

Most arb on modern vehicles resist roll by the bending of the bar itself--------

Jerry, did you even bother to read through the excellent technical paper from Hotchkiss that Jack posted? http://www.hotchkis.net/_uploaded_fi...ons162file.pdf In particular the statement on Page 4?

Companies, such as, Porsche, Daimler-Chrysler, Ford and others have started to include hollow anti-roll bars on factory produced cars and trucks.

I would think that Porsche is interested in a little more than straight line acceleration, but you might also look at Pages 5, 6 and 7 where they point out that by changing wall thickness they effectively tune the stiffness for the application, while still shaving weight compared to the solid bar being replaced.

Steve, again thanks for the lesson in fabrication, and also to both you and Jack for the lesson in advances in material application. Another fine piece of work on a fantastic car! Like DaveS said, hope those heads arrive soon! Looking forward to a video!!

Wellllllllllllllllllllll---------------

A few thoughts for you------------

Anti roll bars are a cover up for a suspension system that has short comings in certain areas of travel --------

Any suspension component must transfer/resist/anchor a unwanted force and to do so will be detrimental to the vehicle in its primary function-----------

A tube compared to a solid bar has certain properties because of the added surface(internal+external) I don't recall the physical law/principle, but it gets a lot of discussion at various times-------

Choices of materials and design in production vehicles comes down to bottom line $$$$$, not necessarily prime choice of methods/materials(production arb(anti roll bar) are generally mounted in soft rubber bushings mainly for forgiveablebility---so as there won't be a sudden transfer of force that could get excessive to mount points----------

Roger----I went back and read the article again and again-----My opinion of it has changed--however its to more negative---The article is more a sales flyer than engineering paper and is full of not only incorrect but poorly stated ----------It mixes use of terms and is far off base as far as topics---1000 lbs torque to stop a wheel?????????// 10 inch DIAMETER? and then using RADIUS?? The person who wrote it doesn't have a very good base of knowledge or experience and would not get a passing grade on the way the paper is written---too many basic mistakes---good thing they had spell check or probably would be mispelled words also-----

And as far Competition Engineering----------they have one item come up on a search and its for an adjustable link for the rear sway bar on a Ford Lightening truck to help correct straight line acceration sorta like I mentioned about Steves bar(tube)

Originally Posted by jerry clayton

Anti roll bars are a cover up for a suspension system that has short comings in certain areas of travel --------

Sorry, Jerry, I don't buy that at all. An anti-roll bar is as much a part of the suspension system as a shock absorber, a spring, a hairpin or an A-arm - not a cover-up. Anti-roll bars have a specific purpose long recognized as a vital part of a good suspension system.

Originally Posted by jerry clayton

Any suspension component must transfer/resist/anchor a unwanted force and to do so will be detrimental to the vehicle in its primary function-----------

I agree that a suspension component must transfer/resist/anchor a force (or a moment). However, I really don't understand your characterization of "detrimental." The primary purpose of most of our vehicles is to provide proper ride comfort (a property unique to each of us), and acceptable performance in straight line, cornering, acceleration and deceleration. Proper transfer of the forces you described will actually enhance the that primary function.

If you meant that enhancing a part of the primary function, such as cornering, another part might be affected, I agree with that.

By the way, I did not find the Hotchkis article to be a masterpiece, but other than the typo substituting "diameter" for "radius," it is factually correct. Also, I wasn't concerned about the 1,000 lbs-ft torque on the wheel. It's just an example with round numbers.

Originally Posted by Dave Severson

Thanks for the chart Jack! Been wondering how to figure the rating of a hollow bar vs. solid. Not near as much difference as I figured there would be!

Great work as always, Steve! Hope your cylinder heads arrive soon, waiting eagerly for the maiden blast on the car!!!!!!

Thanks Dave, I can't wait either, its so close I can taste it !!!

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Welllllllllll--later today/evening I will go back and try to get back into my thought progress that I was in while I was drinking my coffee---now that I am in the ice tea portion of the day I have other things to think about----

But, do you agree that the article was more a sales flyer than an engineering thesis???????????????/

Finished the blades last night.

Just to throw another spanner in the works guys but all our touring race cars use moly tube ARB's, they corner quite hard.


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Steve----what is the wall thickness of the tubing your using??????????Sorry to create controversy??

I was reading some of your posts about liking the 60s machinery-------so do I, except my Pratt & Whitney lathe is supposedly off an early 40s boat----I've got 3 bridgeport mills plus an Index mill, 20 inch bandsaw(new in 1970) 2 Lincoln tig(one new one old) an Linde heli arc that was owned by a company that built stuff for the space program(some of the stuff they left on moon was welded with this machine)

Steve you always make this look fast and simple. In stainless no less! I'm with Dave can't wait to see the maiden launching of the Gumpmobile!

Originally Posted by jerry clayton

Steve----what is the wall thickness of the tubing your using??????????Sorry to create controversy??

I was reading some of your posts about liking the 60s machinery-------so do I, except my Pratt & Whitney lathe is supposedly off an early 40s boat----I've got 3 bridgeport mills plus an Index mill, 20 inch bandsaw(new in 1970) 2 Lincoln tig(one new one old) an Linde heli arc that was owned by a company that built stuff for the space program(some of the stuff they left on moon was welded with this machine)

Jerry thats top secret information Or in other words I can't remember I think its .90" but I will check and let you know, Its what Andy Robinson Racecars use for their ARB's

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Originally Posted by jerry clayton

But, do you agree that the article was more a sales flyer than an engineering thesis???????????????/

Jerry,
I don't see where anyone but you has held the Hotchkiss information to be any type of engineering thesis or analysis?? I simply pointed out that in that information they referenced that several of the OEM's are now using hollow ARB's as a regular part of their design process, allowing them to tune the suspension by simply increasing or decreasing the wall thickness of the tubing. Porsche was one cited, and I find it difficult to imagine that the suspension engineers at Porsche are concerning themselves with pennies saved, nor that they're focused on straight line acceleration. It's purely up to you, but I don't see any need to further pollute Steve's build thread with more discussion of tubular ARB's. Seems that they are widely used in the racing world, as well as in production design, and only a few of us fossils didn't know about it. I, for one, appreciate being set straight and learning something new.

Steve, I really like the final finish on the end pieces. Great work!!