anti-roll bar design

[Ax]

hey guys,
im designing anti roll bars for our car and i have hit a rough patch. i followed the formulae in RCVD( milliken)for doing my calculations to get ride and roll rates for a given cornering situation(first example case in chapter 16) now i realised that the example showed the method for deciding the rate for EITHER front or rear anti roll bars. But if we look at the roll analysis example that follows wherein we specify the required roll gradient, it calculates roll rates for BOTH front and rear ARB's. What is the difference between the 2 examples? Which one should i follow taking into account that this is my first time with an anti roll bar?
Also, we are looking to design a simple U-Bar attached to the bellcranks(push rod system) and the bar running under the chassis. How are such bars tuned for required roll stiffness after installation?

regards

[Ax]

hey guys,
im designing anti roll bars for our car and i have hit a rough patch. i followed the formulae in RCVD( milliken)for doing my calculations to get ride and roll rates for a given cornering situation(first example case in chapter 16) now i realised that the example showed the method for deciding the rate for EITHER front or rear anti roll bars. But if we look at the roll analysis example that follows wherein we specify the required roll gradient, it calculates roll rates for BOTH front and rear ARB's. What is the difference between the 2 examples? Which one should i follow taking into account that this is my first time with an anti roll bar?
Also, we are looking to design a simple U-Bar attached to the bellcranks(push rod system) and the bar running under the chassis. How are such bars tuned for required roll stiffness after installation?

regards

[R. Alexander]

The tech tips here should give you another perspective. I found it clearer.

http://www.optimumg.com/Optimu...Others/TechTips.html (http://www.optimumg.com/OptimumGWebSite/Others/TechTips.html)

[Mikey Antonakakis]

I think most people change the length of the moment arm. A lot of teams also run a bladed moment arm. I.e. you have your torsion bar, and the arms that are perpendicular to it that your tie rods connect to. These arms are thin blades, and can be rotated to adjust stiffness, as far as I know. Depending on your setup and packaging, you could probably also just lengthen your tie rods to adjust the angle of your u-bar, which would change the moment on it. We're running a setup on the 09 car (which was designed for a rear ARB that is just now being implemented, which may have had something to do with our disgusting amount of understeer) where we simply have a few holes drilled in each arm so the tie rod can be attached at discrete radii. Then we have additional adjustability by changing the length of both tie rods. I can't tell you how well it works yet, but it was pretty easy to manufacture.

[Bobby Doyle]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mikey Antonakakis:
...you could probably also just lengthen your tie rods to adjust the angle of your u-bar, which would change the moment on it. </div></BLOCKQUOTE>

Beware of radically changing MR's...

[Mikey Antonakakis]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bobby Doyle:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mikey Antonakakis:
...you could probably also just lengthen your tie rods to adjust the angle of your u-bar, which would change the moment on it. </div></BLOCKQUOTE>

Beware of radically changing MR's... </div></BLOCKQUOTE>
Yeah just for minor adjustments