Hollow or Solid Sway Bar

[wmhjr]

"
Simple question-not debating a 100 lbs lighter will make a difference for all that light weight stuff also added on-just bar A vs bar B.

You mean like when I said....

Most important, like I said - if you're replacing the bar anyway, no reason to NOT get a tubular bar as opposed to a solid bar. If you don't need to replace the bar, then it's probably not going to make a measurable difference.

[79T/Aman]

Here are a couple pics where practice trumps theory, FEA shows the arm under the most stress, this supports my concerns that the arm of the sway bar should not be ignored and a hollow arm will flex more than a solid one, reducing performance, and as seen in the pic eventual failure (yes, no need to tell me that solid bars also fail)
And as you will notice in the pic how a tube bar bend starts to collapse on itself when formed.
And as I mentioned before why would you spend 2 to 3 times as much for a hollow sway bar that needs to be larger and cause interference problem on some cars with zero performance gain

[David Pozzi]

That is a lousy attempt at making a hollow bar!

The hollow bars I've used have no visible shrinkage in the bends. Budget allowing, I would go with a hollow bar for the weight savings, even though it's a small savings and not something you are going to be able to measure. I installed taller upper balljoints on Mary's 2nd gen Camaro, I couldn't measure that either, but I know it SHOULD be better.

That said, I would not try and talk anyone out of running a solid bar if the rate was correct. That one choice isn't significant either way, but if you were to choose the heavier option every time, your car would wind up weighing quite a bit more, and that would be significant. If there are clearance, fit, or rate issues, that needs to be considered in your choice too.
David

[JRouche]

I have to agree. That bar is a poor example. Every hollow bar that I have used is not necked down at the turn. Might be the diff between using a mandrel bender and just a simple roll bender.

And the end of it? Not sure if corrosion had a helping hand in the failure. Or if it failed and was left out to rust. But the way the end is open l am curious to what it looked like new? Not a design I would put in my car. The manufacture of that bar was doing it on the cheap.

One thing that came to mind. For the issue of weight and is it worth it, for such a small weight loss.

Yeah. A driver may not get dramatic increases in performance, may be the same. Most guys like to see a measurable increase for money spent. I totally get that. Thats reasonable and sound thinking.

But thats most guys. Some guys will look at the entire picture and KNOW they have a decrease in weight, as small as it is, its still a real number. So whether their driving performance increases they know they have shaved a pound or two off the front. And sometimes the idea is to keep whittling away at some of the sections that can be lightened up and before you know it you have shaved 50 extra pounds off.

But really, I think looking for a pound or two here or there should be used by a racer. And then there are still so many places to reduce weight. I find it funny to see a guy looking to shave off two pounds at the front and he has a battery in the engine compartment. Or has a steel bumper and not aluminum bumpers. Or has a steel hood and not a plastic hood (and fenders). Or is worse yet running really large heavy wheel and tires cause they look good instead of using race wheels and tires of a correct diameter. Or too much steel and cast iron on the engine when he should have more aluminum.

It seems like there are SO many places on the front end to shave weight that when a guy starts talking about a couple pounds for a sway bar he might have missed some other areas. Racers usually dont. They have all of the stuff I talked about and MORE. Now those guys really can start to talk about the couple of pounds re: hollow or solid bars.

But unless the battery is in the trunk, aluminum top end parts for the engine (and accessories), aluminum radiator, aluminum bumper, maybe some plastic (fiber glass or carbon fiber) parts for the hood and fenders and a lot of other inexpensive changes are made the couple of pounds for the different bars seems like bench racing IMO.

Kinda makes me think of the guy that rides bicycles and spends 4500 on a bike that has titanium this and that, carbon fiber this and that and he is 30 pounds over weight. He might do better with a steel frame bike to shed his extra 30lbs. But thats a diff story.

Im ALL for reducing front end weight. But I think ALL of it should be looked at. And if a guy needs a new bar anyway, yes, I think he should go for the more efficient bar (weight to spring ratio) and continue to look for weigh savings all over the car.

But if a guy has a bar thats working for him (proper spring rate already) and is looking to replace the bar because of the weight issue I think thats a poor choice. Not saying thats whats going on here. But for anyone else looking at a new bar... Its all good. JR

Here are a couple pics where practice trumps theory, FEA shows the arm under the most stress, this supports my concerns that the arm of the sway bar should not be ignored and a hollow arm will flex more than a solid one, reducing performance, and as seen in the pic eventual failure (yes, no need to tell me that solid bars also fail)
And as you will notice in the pic how a tube bar bend starts to collapse on itself when formed.
And as I mentioned before why would you spend 2 to 3 times as much for a hollow sway bar that needs to be larger and cause interference problem on some cars with zero performance gain

[Skip Fix]

Originally Posted by Skip Fix
"
Simple question-not debating a 100 lbs lighter will make a difference for all that light weight stuff also added on-just bar A vs bar B.
You mean like when I said....

No we're talking about a 100lb difference ONLY a 8 lb sway bar swap! You seem to be missing the point he asked for just a sway bar swap.



"That said, I would not try and talk anyone out of running a solid bar if the rate was correct. That one choice isn't significant either way"

"But unless the battery is in the trunk, aluminum top end parts for the engine (and accessories), aluminum radiator, aluminum bumper, maybe some plastic (fiber glass or carbon fiber) parts for the hood and fenders and a lot of other inexpensive changes are made the couple of pounds for the different bars seems like bench racing IMO." My point

Again asking about one sway bar vs the other not a complete lightening gutting setup.

[wmhjr]

Originally Posted by Skip Fix
"
Simple question-not debating a 100 lbs lighter will make a difference for all that light weight stuff also added on-just bar A vs bar B.
You mean like when I said....

No we're talking about a 100lb difference ONLY a 8 lb sway bar swap! You seem to be missing the point he asked for just a sway bar swap.

Skip, no - you're still missing the point.

I have a 79 Z-28 with Hotchkis springs/Bilsteins and Nitto 555's. I have a 1 1/8" factory sway bar on it now. I am looking at either the hollow Hotchkis sway bar 1 3/8" or the Addco solid sway bar
1 3/8". Losing the weight would be nice, but would there be much difference in the cornering capabilities between the two bars?

The OP was for some reason unhappy with his factory sway bar, and was considering replacing it either with an Addco solid bar or a Hotchkis tubular bar. THAT is what this thread was about. It was NOT about whether or not replacing the existing bar simply with a lighter bar made sense.

If the OP had been asking about the performance of the tubular compared to an existing solid bar, then OK. He was not. Since he had already decided to replace the bar, it was a question about whether the replacement solid would outperform the tubular, and vice versa. In this specific situation, there is certainly no ADVANTAGE to a heavier bar assuming the tubular bar can meet the suspension requirements. And since the price difference between the two is negligable enough to be called non-existent, I continue to be baffled by the way this thread has turned.

Furthermore, in a later post the OP stated that he had purchased and installed the Hotchkis tubular bar and performance was apparently improved.

Seems pretty straight forward to me.

[silver69camaro]

I think this thread is going nowhere pretty quick.

[Skip Fix]

"Losing the weight would be nice, but would there be much difference in the cornering capabilities between the two bars? Any advice would be great." So in fact cornering comparisons for a similar sized solid and hollow was the initial question.

Since it is advertised by the manufacturers and said by folks here -the hollow has the same torsional resistance as solid(although one statement was that they are often made larger to be sure they do) due to torsion in the outer portion only and they are better in performance because they are lighter-usually 8lbs or so. It should then pull more gs and have a better lap time if it is in fact better and has an advantage over the solid-not a wash-ie perform the same. Otherwise it is a coin toss.

My entire question was -can we in fact measure this difference between these two bars? Your comment the solid bar has no advantage does not mean the hollow one does have one unless it can be measured. A simple engineering and scientific concept-it is not different if it can not be measured. And all I have questioned-can we measure a 8 lb difference in a cornering car.

Here's a quote from David Pozzi "and not something you are going to be able to measure." Which is my contention.

If not we get back to the coin toss for the decision.

He made a decision, it performs as he would like so we're OK with how it handles-but is it "better"?

[wmhjr]

I give up. I'm going down to my shop in a little while and will hang barbells on my sway bar.

[David Pozzi]

There's a reason I didn't post in this thread sooner. It seemed like it was going to go on and on and on no matter what. I think enough information has been discussed that anyone could make an informed decision on what anti roll bar is best for them.

Skip Fix, what exactly do you want, a vote?
I don't see the point in further discussion, but I'm not going to lock this thread.
David

[MrQuick]

It seems to be one of those threads where everyone is arguing in agreement. I could be wrong.

vince

[Roadrage David]

mmmmm just pickt this tread up and i think its a good one. Nothing wrong with a serius discusion. I have something to say myself . i didnt go tru all the posts so it might have been said alredy, But if there is no mesureble diferense in a hollow ore solid sway bar, could it be that when you have a all out race car with all the ""exstra"" weight savings on the car that are availeble today , that the hollow sway bar is the one to go for, iven the hollow sway bar critics should see and understand that the ""mutch"" lighter car would not put the hollow sway bar under enoughf presure to have it work any diferend then a solid sway bar!!!!!. just in case i runn Helwig solid up frond!. nothing in the rear as i have a mini tubt car with fat tires. simple Hodkish coils DSE leafs koni classic shoks.( no airbag ore coil over stuf just stuf that works) only cars that past me on the former F1 cirquit in holland was the Ariel Atom and a 2010 corvette C6 Z06. i had to let them go due to radiator cooland leak producing smoke!!. caught some c5 c6 corvettes and brand spanking new saleen mustang and new shelby mustang. my car weights in at 3692 lbs with halve a tank, and im the 320 lbs fat guy driving it!oohh pasenger weights in at 175lbs.. http://www.youtube.com/watch?v=mbq-y...layer_embedded http://www.youtube.com/watch?v=Opza1...layer_embedded http://www.youtube.com/watch?v=QSWpn...layer_embedded

[Skip Fix]

David I guess arguing ineffectively with wmhjr that neither bar has an advantage if track times/performance are the same regardless the advertising or engineering theory. Around too many engineers and scientists to take statements as truth without measured backup.

[wmhjr]

I'm convinced. I rode my harley to work today. It had less than half full fuel tanks and I couldn't notice any difference in performance, so I'm not going to fill my tanks anymore. Tomorrow I'm going to check whether or not there is any difference in performance if I disconnect my lights. I'm testing everything on a 1 mile stretch of road, and anything that doesn't result in measured performance differences is going to be discarded.

[zbadone]

Wow, this thread has really taken on it own life. I appreciate everyones input, but like WMHJR said, I was just wondering which bar someone would choose given that the bars were the same diameter, very close to the same price, and that one happened to be hollow vs solid. If they performed nearly the same, then I believe it would be to my advantage to have less weight on the car. Also, just an FYI, the hollow Hotchkis bar was actually $20 less then the solid so I figured it was a win-win. Do love this new bar however. It really keeps the car flat and doesn't push out the front end at all. Maybe I'm just not pushing it hard enough......

[Skip Fix]

"Tomorrow I'm going to check whether or not there is any difference in performance if I disconnect my lights" Well the correct theory to test there is disconnecting the alternator to reduce the HP draw spinning it uses Why do you think so many drag guys are hooked up to battery chargers between runs? Although depending on the electronics and ignition you may loose more than you gain as some folks that do that test have found.

zbadone-glad the sway bar deal worked out and gave you the performance you wanted-after all that's all it is about anyway.Since the two choices would probably be a wash in performance on your car the the hollow was cheaper it was a win-win. The rest is just engineering theory exercises unless you want to buy that solid and do a back to back test them for us

FWIW my old NMCA Top Stock RAIV motor was dynoed with 3 different intakes(all made within 1 hp of each other even the factory HO intake vs the aftermarkets).2 additional on car tested. Had 5 cams, 2 different header sizes, mufflers,2 rear gear ratios,shocks, as well as different timing/jetting setting-so I really don't believe in real world testing to prove what the theories are at all;) So what can I say I guess I'm not so bright to want to try things-even free mufflers for the manufacturer that swore theirs will go faster.

[John Wright]

What I got out of this thread.....with regards to hollow vs solid bars.

With the Hollow bar:

You get to upsize the bar (due to less weight to keep the same front end weight), and gain more bar rate by using the larger, lighter bar.....and that this thread is powered by the Energizer bunny.

[silver69camaro]

Next topic: Mild steel vs. 4340 sway bars and how rate is affected. Discuss!

[John Wright]

Next topic: Mild steel vs. 4340 sway bars and how rate is affected. Discuss!

Hollow or solid?<bwhahaha>

[JRouche]

Do love this new bar however. It really keeps the car flat and doesn't push out the front end at all. Maybe I'm just not pushing it hard enough......

Ya know, Im guilty. I missed the part where you had already changed the bar. My bust. I woulda stopped the exchanges.

Really glad you got the handling you were looking for, and it sounds like you have some extra confidence to take the car a lil deeper or faster into the turns if you want to. But you got some flattening out of the ride and that exactly what you were prolly looking for huh? Good job. JR