C5 Corvette Sway Bar Sizes & Leaf + Coilover Spring Rate Research Notes

While researching coilovers and then subsequently researching why the QA1 coilovers understeered and drove like shit, I took a lot of notes on sway bar diameters along with spring rates. A lot of informaiton I took from other folks and from various forum posts. Here's my collated information from researching these things.

Swaybars

Leaf Spring & Coilover Springs Rates

General Notes On My Findings

• Article from grassroots motorsporst researching and testing coil vs leaf effective spring rates. (TLDR: Not a direct comparison between the two)
• Ultra informative post on measured rate vs stated rate of leaf springs versus coilover springs (TLDR: Extreme leafsprings about Match 500lb coilover springs)
• Differentiation in spring rates on front versus rear is due to leverage ratios. If you look at the rear control arms with a coilover in them versus the front, the front is morevertical, the rear is less vertical. Thus the rear of a C5 corvette will compress the rear coilovers more for the same amount of suspension travel, thus requiring a higher spring rate to help balance the car.
• Spec Corvette runs balanced spring rates and compenstes for it with huge sway bars supposedly. Reviewing sway bar sizing, that very much appears to be the case!
  • Per conversation with a fellow who ran spec corvette for two years, he too wanted to run higher rear spring rates but instead was able to get the handling he wanted stiffening the spec corvette rear sway bars, which are already pretty thick per my findings above.
• I spoke with the gentleman who helped develop QA1's coilovers, and he ran 550/650 spring rates per his testing, and is what he recommended QA1 runs, Not sure why QA1 didn't follow that and instead went with 550 squared.
  • QA1 does have a 700lb spring available they can send. Eibach of course makes 600lb and 650lb springs with a 2.25" ID.