Solid vs. Hollow Sway Bars

[DILYSI Dave]

Not sure how much it goes into the thought process for a swaybar, but hollw would be stronger torsionally than a solid bar. There is more surface are resisting torsion than a solid bar. Same idea applies to gun drilled axles. It saves weight, but makes the axle stronger as well

Incorrect. Hollow is stronger for it's weight, but solid will always be stronger given the same OD and material.

 

[NoTicket]

So, does anyone have any info on the actual weight of the Whiteline sway bars? I have been searching this forum and the rest of the internet and haven't found it. In the how much does it weigh thread the stock bar is weighed in at 13.8lbs, but I don't see the Whiteline bar weighed anywhere.

 

[Roadracer350]

I have my weights written down at home but it will be a couple days before I'm back.

 

[Full_Tilt]

A hollow bar can be stiffer and lighter than a smaller diameter solid bar. There are packaging issues with large diameter swaybars which is why its common to see them made solid on many cars where the stiffness is needed.
This is why roll cages are made out of tubing and not skinny solid bar. Tubing can be equally strong but lighter.

Another example would be cars with DeDion suspension. In order to keep it light and very stiff (ideally it does not flex at all, unlike a swaybar) you typically see the DeDion tube made out of large diameter, thin-walled tubing:

 

[JAJ]

Don't mix up stronger and stiffer. Stronger is whether it will break, while stiff is how hard it is to twist.

Stiffness of a torsion bar is proportional to the fourth power of the diameter, which is a really high factor. A 19% increase in diameter is a 100% increase in stiffness. The stiffness of a hollow bar is just the stiffness of a OD bar minus the stiffness of an ID bar. Putting it another way, a 1.19" OD hollow bar with a wall thickness of 0.19" is the same stiffness as a 1.00" solid bar, but it only weighs 42% as much. And it's only 42% as strong, so while it's as stiff, it's more prone to crumpling or breaking than the solid one. If you went to a 2.00" OD bar, the wall would only be 0.032" thick to create the same torsion as a 1" solid bar, and it would weigh only 13% as much. But the wall would be so thin that under most uses, it would just crumple the way an aluminum can does when you twist it.

 

[Department Of Boost]

I would think we could leave peoples driving skills out of the picture and talk objectively about tech instead of kiss assing a bunch of your favorite drivers.

You sound like you're just justifying your decision.

Not trying to bust your balls, but it sure SOUNDED like you were saying that unless you're Terry, Sam, or have a national title, there's no way you'll feel a weight reduction in the car.

And again, yes you kind of did imply it when you brought up your titanium IoM bike failures. While I agree that lighter is not necessarily better, there was no reason to even bring up the example unless you were trying to imply that a tubular (lighter) swaybar may have the same durability issues. With the wall thicknesses needed to give the correct "spring rate," there's no chance that simple use or basic track abuse will cause it to shear in half.

I'm really not trying to bust your balls, I'm just pointing out that what and how you post can have a profound impact on the message you're trying to convey...

Patterns.

 

[NoTicket]

So does anybody have those Whiteline sway bar weights?

 

[Sky Render]

So does anybody have those Whiteline sway bar weights?

http://www.whiteline.com.au/product_detail4.php?part_number=BFF55Z

http://www.whiteline.com.au/product_detail4.php?part_number=BFR65Z

Those are the packaged weights.

 

[Roadracer350]

Patterns.

Oh look... Here comes King of the Mustangs spewing his crap again... Enlighten us common folk.

 

[Roadracer350]

I talked to a couple drifters today( no not road racers ) and they are running solid bars due to they HAVE broken hollow bars in crashes. One of them runs a 240 with a LS1 an the other runs an older Supra with a 2JZ. The 240 guy said he broke a Tien bar when he crashed into a barrier. Not saying this would happen on our cars but just putting it out their.

 

[BMR Tech]

I agree with what has been said, in regards to the same rates - one hollow, one solid - it would be better to go with hollow.

We would never make a solid front bar. There would be no reason to, unless we wanted our customers to shop our parts based on price - but that's not us.

When modifying a car to perform at it's absolute best, I believe it is silly to pick a heavier part over a lighter part, assuming both parts are similar in performance and price.

I don't understand people justifying, or trying to, a "minimal" weight difference. Weight is weight, and it all adds up.

 

[modernbeat]

So does anybody have those Whiteline sway bar weights?

You know you can always come to us for weights.

Whiteline bar:

Eibach bar:

There are some middling reasons for going solid. But it's usually fitment. With the Eibach bar we rubbed the bar on the tires and the end links on the inner fender wells (slightly). With the Whiteline we have no rubbing. And while we'd like to have the lightest car possible, or have the weight on the rear, once you are competing in a class with minimum weight limits that require you to run a full tank of fuel AND additional ballast, the additional hardware weight is moot.

 

[SoundGuyDave]

There are some middling reasons for going solid. But it's usually fitment. With the Eibach bar we rubbed the bar on the tires and the end links on the inner fender wells (slightly). With the Whiteline we have no rubbing. And while we'd like to have the lightest car possible, or have the weight on the rear, once you are competing in a class with minimum weight limits that require you to run a full tank of fuel AND additional ballast, the additional hardware weight is moot.

You make some very valid points, BUT, even in the weight-restricted series, there are choices that can be made... Go with a lighter front swaybar, and leave the spare tire in the back... Instant rearward weight distribution. There are also a LARGE number of "cheatey" ways of doing things like this. There are no CCR restrictions on placement of a cool-suit cooler, so you could mount it in the right rear for optimum weight placement. Need more? Dynamat the spare tire well, underneath if you want. Weight is low, and all the way to the rear. I guess what I'm saying is that there would have to be a pretty solid reason TO run a solid bar, rather than a hollow piece. Fitment is certainly one of those reasons. On the S197, though, it's just not that hard to find a hollow bar that will clear what you need it to clear. If the Eibach rubbed, and you know where, just find a hollow bar of the appropriate rate that has extra clearance there. Try Strano's bars, try the FRPP bars, try the BMR bars, etc. I just can't see the ONLY solution being a solid bar. 5lbs isn't much, but adding that weight is just going in the wrong direction, particularly up front.

 

[BMR Tech]

Interesting. Our bar is substantially lighter than that Eibach. I actually have one by the scale as I type this. Pic to come in 5 minutes.

 

[BMR Tech]

Our 35mm Hollow Bar is 15lbs on the nose, with the bushings and wrapping attached.

 

[NoTicket]

So the Whiteline bar is about 6.5-7lbs heavier than the BMR and is 7.7 lbs heavier than stock.

It sounds like the only reason to use it is for fitment of large wheels and tires in tricky situations.

 

[BMR Tech]

Well, it also depends on the rate you desire.

If the WL piece achieves a higher rate than ours, or anyone elses, and the user needs that rate - well, then that piece would be the route to take.

There was a thread about sway-bars quite some time ago, and the rates never popped up for the WL part. Maybe the Vorshlag guys can share the rates. I would be interested to see what they are. If they don't want to do it, I can do it in 30 seconds if they will provide me with the bar thickness, bar length, and lever arm lengths. It may not be 100% accurate, but would be an easy way for comparison.

 

[Sky Render]

I use the Whiteline parts because I wanted a rear bar that was easily adjustable and 4-way adjustable. I believe in using "matched" front and rear sway bars because it's easiest to dial in your setup that way. There's no guesswork as to which bar is stiffer.

 

[Roadracer350]

Our 35mm Hollow Bar is 15lbs on the nose, with the bushings and wrapping attached.

Ok do your bar is 15lbs. What all does it come with? Adj end links? Lateral locks? How adjustable?

 

[Roadracer350]

I use the Whiteline parts because I wanted a rear bar that was easily adjustable and 4-way adjustable. I believe in using "matched" front and rear sway bars because it's easiest to dial in your setup that way. There's no guesswork as to which bar is stiffer.

This is why I went with the whole Whiteline system but but apparently people want to pull excerpts from my posts and put words in my mouth.