2005 Ski-Doo Racing Handbook, Page 119Get this manual
SECTION 04SUSPENSION SC-3 SC-4RAS
THE SC IV REAR SUSPENSION
All suspensions in the past have been designed with the fact that the rider was sitting over the rear armWith this in mind, engineers have designed most of the bump absorption into the rear armThe front arm was for the most part looked at only as means of adjusting weight transfer and has always been of falling rate designThe SC-10, IIIII are both excellent suspensions and have been finely tuned to work very well over the past few yearsHowever with the advent of the REV and it's forward riding position engineers decided to rethink and improve the rear suspension