Rear Sway Bar
 

With my front strut bar, coming close to completion, its time for the next project.

I wanted to make a Rear Sway Bar, kinda like this:

http://images.soliton.net/protege/te...t%20piping.jpg

http://images.soliton.net/protege/te...Suspension.jpg

This picture is obviously from the MP3. Looks really good, just wondering what would really be involved in making one like this?? Does the bar have to be an actual BAR? Or can it be square with rounded corners??

Sounds corny, but just want some help/details on how I can make it look good, cuz usually a rear sway bar can be seen if you're driving behind a car.. I'll probably anodize it red as well...

the reason why most bars, if not all are circular, is because a circle is stronger than a square, or a shape that has flat sides.

Re: Rear Sway Bar
 

Some anti-roll bars are tubular (for weight savings), and the trailing arms can be made out of flat stock (common for custom applications). But a box section bar would be a bad idea, because it is loaded in torsion (twist). The edges of the box create stress concentrations, which would tend to bend and not bend back.

The math for how to build equivalent stiffness is too complicated, but essentially, stiffness is radius (or diameter) to the 4th power. And a tubular bar would be the stiffness of the outer diameter minus the inner diameter. A 24mm tubular bar of 2mm wall thickness would be slightly (7%) stiffer than a 20mm solid bar, assuming the same material, with only 44% of the weight.

Hope this helps.

interesting... =) thanks for the info...

I guess I can always get some 1/2" - 3/4" piping, and just get the guy next door to weld on some pieces at the end, which I can machine out on my dad's machine to fit on the car.

Would I need to do any mod's to my car to have it fit?

Obviously it has to meet certain specs. Thats why I was thinking of getting my Mazda dealership to order one for me, so I can get the specs of it, then make my own. If it doesn't work, I can always trash it, its only my time I'm using up...

I would also really recommend against welding a swaybar. Welds tend to break when they're loaded in shear (i.e. loaded parallel to the direction of the weld) and the average welder typically doesn't have the skills or the equipment necessary to lay down a weld that's strong enough to withstand the repeated twisting forces that a swaybar is subjected to. Welds also tend to weaken the metal surrounding the weld and make it more vulnerable to corrosion. Summary: this is a REALLY BAD IDEA :eek:

I really, really don't think you should try this. It is not "only your time" that you're using up. If your homemade bar breaks in mid-corner (which is when it will break) your car's handling characteristics will suddenly change drastically. This may mean wreck, which may mean serious car damage, personal injury or DEATH :(

There are better things on your car for you to mess around with. If you're determined to have a pretty red swaybar, pull a stock bar off a junkyard car and have it powdercoated :)

Is it just me, or doesn't the middle of the bar need to be round because it pivots in the frame bushings as the suspension moves up and down.

Not the first time I've been told that... :confused: