Solid vs hollow sway bar

[tremolo]

In terms of handling, what's the difference? Is one inherently stiffer than the other

Let's say you've got 2 bars:
1. 22mm solid
2. 24mm hollow

Which is stiffer (as a rule)?

[Gammaboy]

Depends on the wall thickness.
You can make the 24mm hollow the exact same stiffness as a 22mm solid, but it'll be lighter.

[PLAYA]

with torsion its stiffness is like the radius^2 ( i would have to check formulas again) anyway point being you are HEAPS better off getting a larger diameter thinner wall tube then a solid bar. The centre of the bar is doing effectively very little.

[GTSBoy]

stiffness is actually proportional to radius^4. So the outer part of any bar does simply masses more for stiffness than the inner.

So if you take the 4th power of 22, get 234256.
take the 4th power of 24, get 331776.

Take the difference between these, get 331776-234256 = 97520

Take the 4th root of 97520, get 17.6.

So you can have a 24mm hollow bar with a 17.6mm hollow section and it will be the same stiffness as a solid 22mm. It will also weigh only 55% of the 22mm bar.

[denmaster]

GTSBoy FTW. Of course, this assumes they are made of the same material...

[tremolo]

Awesome, thanks fellows.

I bought a replacement OEM front sway for my car - the original was the hollow & the new one is solid - and was curious.