Threshing on the 70 Series STS Combines is accomplished with the combination of TriStreamT™ crop flow, stair-step top covers, and pull-and-release tyne separation to let the machine cut into the worst conditions and come out with more grain.

The STS Bullet Rotor™ has been designed to increase material handling, offering increased throughput in tough crops, consuming less horsepower, and extending harvesting hours. Customers will notice how much smoother the crop is handled through the threshing and separator at higher ground speeds, without any compromise to the high grain quality and crop versatility for which STS combines are well known.

The Bullet Rotor is standard equipment on all 9570 STS, 9670 STS, 9770 STS, and 9870 STS Combines. The rotor features a coned front, giving more room for a higher volume of crop material fed from the TriStream™ feed section to enter and be distributed more easily and evenly. Crop slugs are minimised in the coned area more effectively, reducing separator noise in damp tough conditions.

To enhance the improved material handling of the Bullet Rotor™, rifled threshing elements give superior indexing of the crop, moving material through the separator at a controlled speed to optimise separation capacity.

• Bullet Rotor™ technology reduces the force required to move material through the combine by as much as 20 percent. Less power is required to drive the rotor, while ground speeds can be increased; this easier, smoother crop flow reduces the potential for rotor 'growling' at high feedrates, even in damp conditions. This is especially beneficial when harvesting early or late in the day, or at any time conditions impair crop flow.
• The 'rifling' grooves on the elements allow the bullet-shaped rotor to move large volumes of crop material through the rotor more efficiently. Rifled elements 'grip' crop material, providing a pulling action to help even the crop flow, allowing the rotor to deliver better threshing performance.
• Heavy-duty vanes on the top cover of the STS module help propel the crop rearward through the threshing and separating system. Unlike conventional rotaries, STS module vanes never need adjustment.
• The John Deere STS module features a stair-step design. This gives the crop mat room to expand as it travels through the separator module, reducing the chances for roping - and lowering power requirement. THe pull-and-release action frees trapped grain in the crop mat, boosting grain savings significantly.
• Separator tynes feature high-strength materials, a short breakpoint design, and a wear-resistant Gopalite TS coating for increased life (Optional).
• The optional Extended-Wear separating package doubles the life of components, and includes factory-installed extended-wear concaves, extended-wear threshing elements and separator tynes, and extended-wear rotor top covers.