Sway bar differences?

[ChargerST]

What's the difference of a hollow and solid sway bar performance wise? I know that the hollow ones weight less but are larger in diameter. Summit sells the hollow Hellwig bars for $163 (55904) and the solid ones for $193 (5904). I always thought that the hollow ones are more desirable because of reduced weight and added stiffness?

[HPP]

A hollow bar will have reduced resistance compared to an identically sized solid bar, which is why they tend to be a larger OD. A 1.25 hollow bar should be close to the same resistance of a 1.125 solid bar, so there is a reasonably close interchange. Since so many cars out there still use bars that are under 1", going to a 1.125 hollow bar will help step up performance while loosing weight, both good things.

[Mike DC]

Yeah.  The hollow bars are really not quite as stiff as the solid ones.  But when you swap out a solid bar for a slightly larger hollow bar for the same final resulting stiffness, the latter hollow setup weighs less than the original smaller solid bar did. 

[ChargerST]

So getting the 1 1/4" hollow bar saves weight and money compared to the 1 1/8" bar while retaining the same stiffness? Interesting 

Only issue would be if I can fit a 1 1/4" through my 70 Charger K-frame.