2004 Polaris Touring Service Manual, Page 231Get this manual
SUSPENSION Round Springs vs Square Springs
Many snowmobiles now utilize square profile rear torsion springSquare springs are lighter in weight (1.5 lbs, and smaller in packagingThe square coils take up less room, therefore allowing the carrier wheels to be positioned more inward in the tunnelAnother benefit of the square profile spring is the ability to maintain the same characteristics of the round spring, but have fewer coils of wireNOTE: The square profile springs will not retrofit to previous modelsThe length of the coil stack is shorter on the square springs and the inside diameter of the coil stack is also smaller