I run 17.5 on an indoor carpet track and just switched to a 3 gear setup. I could feel the difference immediately. For me the truck always felt like it was "tippy" and on edge. Now it just feels smoother everywhere on the track to me. i was faster and more consistent than the prior week, motor temps were down as well.

To be fair I also switched from running an inline shorty pack to a saddle pack at the same time so Id bet that added to it being more planted as well.