I have read a lot of post on hear about gearing on Pro S model sleds. I was under the impression that the Pro S model switchback 800 had 23/37 (1.61 ratio). So I wanted to gear the sled down for better performance. After a few hours of tearing the sled apart I was surprised to find the sled had 22/37 (1.68 ratio). I wanted to go to the 22/38 (1.73 ratio), but I would have probably not went through the hassle if I would have known the 2016 Pro S came stock with 1.68 ratio. I am still going to switch them out to the 1.73 ratio.