When Fox first hit the market, they used a simple single rate negative spring. This design worked great for shorter travel bikes, but around 150mm and above you ran into issues. The pressure difference between the air chamber and the negative spring meant that lighter riders would lose travel, while heavier riders would sometimes have top out issues.
Over the years, Fox’s technology has evolved substantially. They’ve gone from a basic coil to multi-rate springs, with bottom bumpers, and finally full negative air springs.
To learn more about how negative springs works, the positives/negatives of each generation, and gain insight into the manufacturing process, hit play. The crew at Vorsprung Suspension does an incredible job of breaking all this information down into easy to understand language.
For more info, visit vorsprungsuspension.com.