Cornering Dynamics - BOMBARDIER 1996 Ski-doo MX Z440 Handbook

CORNERING DYNAMICS

The ideal situation, while going through a turn, is to keep the snowmobile as flat as possible
without the skis or track losing contact with the driving surface.
As you enter a corner and turn the skis, the rest of the vehicle will want to continue straight ahead.
If the skis do not bite the surface, they will start slipping and the vehicle will not turn as tight as the
skis are turned. This is called "understeering" or pushing. If the skis bite very well and the track
starts sliding out, then the vehicle is "oversteering" or is said to be loose. If the ski and track
traction is balanced, then the vehicle will maintain a good "line" though the corner. Because the
center of gravity of the vehicle wants to continue straight ahead and because the center of gravity
is above ground level, weight will be transferred to the outside of the vehicle. This causes the
machine to roll to the outside. As the radius of the corner gets tighter and/ or speeds increase, the
machine rolls more, and more weight is transferred to the outside of the vehicle until the front or
back loses traction or the vehicle tips over.
Roll can be reduced by installing stiff springs on the front suspension and/or a lot of preload, but
this will cause a harsher ride than necessary. Lowering the center of gravity will also reduce roll but
there are practical limits as to how low the center of gravity can go. Most vehicles are equipped
with an antiroll bar or "stabilizer" bar. Common terminology will refer to it as a "sway" bar. (It is
have lever arms from 3" to 7" in length. The ends of the levers are connected to the front
suspension. As the outside suspension is compressed during a corner, the bar is twisted and
forces the inside spring to compress also. The bar is "borrowing" spring pressure from the inside
spring and adding it to the outside spring. The suspension can now resist more chassis roll
(see following illustration).
Section 03 CHASSIS PREPARATION
03-27