what you didnt know about track noise
Amsnow
50% OF ALL NOISE is produced while riding a snowmobile that can be attributed to track noise. Many people believe falsely that the vast majority of sound coming from a snowmobile is from the engine. This was true with the loud pipes of a couple decades ago. With advancements in engine technology and exhaust design technology, this is no longer the case. In addition, tracks create significant levels of vibration and harshness.
Ski-Doo has been ahead of the curve combating track noise with their SilenTrack technology on numerous touring models for several years now. The following is from a technical preview of the new 2014 SilenTrack2.
“The original version of SilenTrack Technology debuted in 2010 and reduced sound by reshaping the interior surface of the track to compensate for the bumping of the idler wheels against the track reinforcing rods.
SilentDrive for 2014 goes much further, evolving into a system of track drivers, track design and modified suspensions. The result is a 70% reduction in vibration at cruising speed. New 1.43 pitch track drivers are the key to the system. They are perfectly round and interface with the track using 16 smaller lugs to engage complementary track lugs. They are positioned in the center area of the track and are internal drive only. Doubling the number of lugs reduces the load on each one, reduces sound, backlash, and vibration. This also separates sprocket frequency from track frequency, reducing vibration and harshness. The sprockets are painstakingly engineered to reduce ice and snow buildup on the drivers for increased efficiency.
For Ski-Doo’s SilenTrack2 several modifications were made to the interior track design. The center of the track has twice the number of molded lugs to interface with the new sprocket design, so they engage smoothly and quietly. The area in the center of the track is thicker to increase rigidity in order to reduce noise and vibration. For 2014, the Silent DriveSystem is available on the Grand Touring LE model with the rMotion 137 rear suspension. On this version of the rMotion suspension, the rails are made longer at the front to eliminate the sound of the track flexing between the drivers and the front rail tips. And the idler wheels are mounted 1.4 in. (35mm) more forward, eliminating track slap when the suspension compresses.”
In conclusion, the SAE and several OEMs have been working with new ways for coating or wrapping rear suspension idler wheels as well to dampen track noise. You will be seeing more from all the OEMs in the future as the industry combats increasing noise restrictions. More info: www.SAE.org. For more info on Ski-Doo’s SilenTrack technology visit: www.ski-doo.com