Short tunnels is a big innovation in the mountain machine industry. It’s the second year of production line machines having this feature for BRP. In 2020, the Summit X with the expert package was the only machine with it and in 2021 it is on every Summit X and Summit X with expert packages.
Origin
This trend originally dates back at least 4 or 5 years with Chris Burandt modifying his Polaris Pro RMK’s this way. Basically, short tunnel machines distinquish themselves from traditional machines by either cutting off 5-6 inches the ass end or instead of putting a 165″ frame on a 165 track and suspension, BRP puts a 154′ frame on a 165″ track and suspension (or in the 154″ they use a 146 frame and a 154 track and suspension). This results in having the track sticking out further than rear bumper.
I am in my second season riding Summit X’s with the expert package (2020 and 2021 machines), which includes the short tunnel. There is a noticable difference that takes shape in a few different physical traits.
Characteristics
First of all, the bumper being shorter than the lag and a transformed mudflap that sticks out straight out the back instead of going downwards to redirect the snow to the radiators. When you are plowing through very deep snow and spinning the lag most of the snow is shot out the back, unlike with a mudflap where lots of snow is redirected to the front of the machine under is belly. All that snow that was shot in front under the belly of the machine caused much resistence. So moving forward is now eased with the snow being shot out the back.
Secondly, the bumper not being the furtherest piece in the back when spinning or trenching downwards in deep powder, the lug is the part that sticks out the most. While becoming in difficulty from going deeper and deeper usually the bumper would grab or rest on the snow the same way someone snowshoeing does while walking on snow, thus preventing the machine from going further down. When this happens, the lugs would wash away the loose snow and you weren’t going forward anymore, so you’re stuck. But now with no bumper shelving you on the snow as long as you are moving, it will go deeper but you continu going forward and get out of a bad situation instead of being stuck. Having most of the snow coming out the back and not going under the front of the machine helps tremendously once again.
Another great advantage from the short tunnels compared to traditionnal machines is how much it is able to backup. I know we are supposed to only go forward but while exploring new terrains often it is impossible to turn around easily. The darn mudflaps on tradition machines stops the machine from backing up almost immediately, where as with no mudflap’s the sled is able to back up much further and not put you in a bind.
Negative side
All this greatness comes at a price, not having any mudflap at the back of the machine tends to overheat the motor much more easily due to the lack of snow going on the radiators. With the ice scratchers, it helps a whole lot. Not having any mudflap also causes a blizzard like effect behind the sled for those who are following you, even golf ball size hard snow is projected in the air.
