Last season could do 122/109 at most anytime. This season 115/103 consistent (speedo Vs GPS). Suspect listed items; Weather and snow, although have run hard packed roads which usually is the best. Can't run ice, not studded, changed gears from 24/38 to 23/38 added Sly Dog skis with ski savers and triple edge carbides, change suspension from Mono to ZX2. With all of these at one time impossible to pull the rabbit out of the hat, but suspect gear ratio and ski savers as most likely. The ZX2 has a much gentler approach and trailing profile and large rear idler wheel, weighs about 5 lbs less and is a great improvement in ride and handling over the Mono. Don't really care about the speed loss at it isn't all that important, not what I bought the ER for. Speed would have been a Doo or Cat. Torque of the 4 stroke is the greatest reason and no disappointment there. Will start back by removing ski savers, then if no help gear ratio. The ZX2 stays regardless. Just looking for opinions.