Weâ€™ve heard from a number of vendors and shops in regards to issues with track tension caused by the installation of larger diameter rear axle wheels in 121â€ machines. The use of the stronger aluminum wheels adds strength in corner tail landings, and installing larger diameter wheels into long track mountain sleds has been fashionable for a number of years.
However, when larger diameter wheels are installed on shorter tracked sleds there are often problems with varying track tension. In some cases, sleds will tighten the track so much through the suspension travel that it becomes a limiting factor in the total travel. Suspension engineers spend great effort in designing the geometry so that the track tension is maintained within a â€œwindowâ€ of acceptable tension through the entire travel. Simply adding larger wheels to this engineered device can disrupt the tension throughout the travel.
Weâ€™re told the larger wheels do not provide any measurable gains on the shorter track sleds, other than the strength increase (aluminum) and cosmetic appeal. Snow and ice stick to the aluminum ones more often, so there is no weight advantage in the field. The track tension variation is the biggest concern. If a rear suspension has been engineered with the larger wheels, it should work properly, but adding the larger wheels to shorter track sleds should be carefully reconsidered.