It’s rare that we get on the snow in early November but this year we did and found late December conditions with a bit of a base and 4 foot of snow pack in the upper elevations. Instead of just going out for a break-in road ride we were able to perform a more realistic first impression of the production 2018 Polaris PRO RMK 800. We rode around 40 miles and put just a hair under 2 hours on the engine.
Polaris announced several off-season updates that we were not able to experience in late spring when we rode the 2018 prototypes. The cooling system has been changed with a new thermostat, coolant routing and head which they claimed increased flow and dropped engine temperature.
After 10-15 miles of break-in time we began to compare water temperatures to a 2017 RMK we had along on the ride. We ran the trail without ice scratchers just to see what the temps would do and we never saw higher than 125 degrees. In the deep snow on hard pulls the 2017 averaged around 122 degrees while our 2018 stayed around 95 degrees. To be fair the 2018 is still in the factory break in mode so we will continue to monitor any changes after break-in but our initial ride showed engine water temps on the 2018 model have been noticeably reduced to the previous year’s models. Cooler water temps generally equal better horse power but we will need to get more break-in miles before we can see the full effects of the updates.
Polaris also updated the shock calibration for 2018 RMK monotube Shocks with new “Hi Flow” Walker Evans pistons on the front suspension and rear track shock. Our initial feeling is that the 2018 calibration is improved over the 2017 models however the stock rear spring factory settings were a bit soft for our 200-pound test riders. The rear shock would blow through the stroke faster than we prefer and would bottom easy for any rider over 160 pounds or riding a faster pace. We stopped and adjusted the rear spring preload 3 turns tighter which really helped the shock ride higher in the stroke and keep the chassis flatter through the rough patches. The front shocks felt good and compliant, so we chose not to touch the preload.
We will give more evaluation details after we have more miles but for now we are happy with the updates over the 2017 model.