Traxxas 6867 rear springs (+10% rate) are a pair of stiffer coil springs designed to increase rear suspension support by about 10 % over stock on 1/10‑scale Traxxas 4×4 models like Slash 4×4, Stampede 4×4, Rustler 4×4, and Rally; these springs help maintain ride height, improve handling under load, and reduce bottoming on jumps and rough terrain for more controlled performance.