While Polaris boasts about their â€œnewâ€ driveshaft design on their 2005 IQ chassis models (Fusion 900 & RMK 900) this hollow driveshaft was actually found on the 2004 Pro-X models, with little fanfare.
This new design is two pounds lighter (thatâ€™s rotating mass) for quicker acceleration. Itâ€™s a full three inches in diameter, with external steel splines that provide a 400% increase in drive sprocket retention. Itâ€™s also 300% stiffer for reduced flexibility and less ratcheting. Being two pounds lighter amounts to a 10% reduction in rotational inertia.
So what we have here is less weight, less track ratcheting, less flexing, and better power transfer. This also allows for less material in the plastic drive sprockets, allowing 9-tooth drivers for improved efficiency. The overall diameter is more consistent for less run-out and friction loss, resulting in reduced rolling resistance and improved drive cog to track engagement. Thereâ€™s also a reduction in backlash when braking, due to the wider cog being stiffer. Bent drive axles are now far less common in extreme conditions. All part of the â€œintelligentâ€ drive train found on the 2005 IQ chassis from Polaris.