• C5 Base Suspension: 23 mm-front / 19.1 mm-rear / 3.81mm/2.0mm thickness
  
• C5 Z51 (97-99): 25.4 mm-front / 21.7 mm-rear
  
• C5 Z51 (00-04): 28.6 mm-front / 23.6 mm-rear / 4.15mm/3mm thickness
  
• C5 Z06: 30.0 mm-front / 23.6 mm-rear / 4.5mm/3.5mm thickness
  
• C6 Base: ?? mm-front / 22.0 mm (7/8")-rear
  
• C6 Z51: 31 mm-front / 25.4 mm (1")-rear
  
• C6 Z06: 31 mm-front / 28.8 mm-rear
  
• C5 Hotchkis: 31.75 mm-front / 25.4 mm-rear / 4mm/4mm thickness
  
• C5/C6 Addco: 32 mm-front / 25.4 mm-rear
  
• C5/C6 Addco: 35 mm-front / 25.4 mm-rear
  
• C5 Pfadt (Adjustables): 32 mm-front / 26 mm-rear
  
• C5 Pfadt (Adjustables): 35 mm-front / 28.5 mm-rear (Pfatty)
  
• C5 T1 (GM Racing): 38.4 mm-front / 27.5 mm-rear / 6.35/6.35 thickness
  
• C6 T1 (GM Racing): 38.4 mm-front / 27.5 mm-rear / 6mm/?? thick
  

Hollow? Wall thickness? Solid? Why does it matter? How can something hollow be stiffer than something solid? Does arm geometry factor in?

What role does a swaybar really play? Soft springs, big bars? Big springs, soft bars? Moderate & moderate?

Why tie an independent suspension together with a big bar? Why not? Why would engineers not design a chassis that could work solely with springs? Why throw swaybars in to the equation? Would the spring rates required simply be too much? Couldn't truly progressive rate springs solve this?

Is a large part of this dilemma because the wheelbase is so much more than the track width?

Sway bar stiffness is determined by two things, torsional moment of inertia, and length of the torque arm at the end of the sway bar. Most cars don't have adjustable or different length torque arms at the ends of the sway bar, so the differences between Z51, Z06, base, etc, are due to torsional inertia.

It's proportional to the difference between the 4th power of the OD and ID. The OD has a huge effect, and the material in the middle of the tube adds more weight than stiffness, so some bars are hollow. The hollow bar would have to be a bit larger than the solid bar to be equally stiff. (Or it could have shorter torque arms on either end.)

I can't speak on why it's needed. My guess would be that springs alone could be made stiff enough to be equivalent to the bar, but the car would ride like shit everywhere else. I don't think wheelbase has much to do with it.

wheelbase, as I understand it, has more to do with stability and transient response than anything else.

I have always preferred hollow bars, if only to save the weight.

Quote:

Hm. I was wondering if it was the distance from the CG to the actual weight that could let the spring rates be lower if only controlling front<->rear weight transfer, and that's why we needed to add left<->right roll stiffness with swaybars on top of the springs.

Or is it simply that we can generate more cornering force than braking or acceleration forces? Is that statement even true or can we generate the same forces?

I am a little confused, somewhere over the years somebody told me that with a solid bar and a hollow bar of the same diameter the solid bar would be softer. I never understood that -- it sounds like you're saying that's not true? Also, if the formula says (OD-ID)^4 won't the material required to make an equally stiff hollow bar come to the same amount of material?

Just realized the formula you gave is probably OD^4 - ID. So an OD changed is much more drastic...

OD^4-ID^4

The material stiffness also gets multiplied in.