Open the concave as much as you can and slow the rotor down as much as you can. Keeping it full and cutting lower helps a lot too. We have baled behind an STS, obviously straw quality is not like an walker but it is doable.
Don't worry about elvie, I have yet to see a positive comment from him on anything.
With the neighbors Axial flow (don't know anyone with an STS) he always cut the wheat as high as reasonably possible and then would go back in with a mower-conditioner and cut it like hay. Takes longer but if straw is that important.
Do they make anything to replace the tines on the back part of the rotor? Some kind of smooth rub bars like on the front part of the rotor or an axial flow? Seems like the tines would act kind of like the Estes disrupters and really shred the straw. I've never baled behind a sts so I don't know. I've baled plenty behind an axial flow and it makes fine straw as long as the machine has a beater instead of a chopper and/or the straw is a little green or damp. I would definately cut the wheat you want to bale early in the morning or late at night when the straw is tougher
I bale 4000 acres of straw every year with half of it being cut by an STS machine. I don't have any problems. Like someone said earlier, run the rotor as slow as you can and the concaves as open as you can.
Almost everyone around me bales behind an STS, with a few red machines thrown in there too. Some of our success i would attribute to the baler. Hesston 2190's. I have demoed both the Krone, and the New Holland, and while they do a good job in hay, the Hesston seems to make a better bale in the straw.
Breweye this might not work for you but if you have airation on the farm I would try what we do. If you start harvesting your wheat at 17 - 19% moisture you will not only get quality straw but also get a better sample, ( less white caps & #1 Wheat in the bin before any rain downgrades it. Less white caps may be a bit hard to understand. I find that the new varieties we are growing are bread with tighter hulls to protect it from fusarium. As the wheat dryes down the hull seems to get even tighter creating white caps. When I bought our 9770 I thought It would be the end of thrashing at those moisture levels but thankfully I was wrong. Just something you might want to try. Good Luck!
We also cut most of our wheat at 17-19% for the same exact reasons. When we bale straw behind our STS we only drop early in the morning or after a bit of a dew after dark, and I would say the straw is just as good as any conventional would be. We dont have net wrap but the ones who do seem to bale day and night in the chaffiest of windrows.
The one variety of wheat we grow (sable) has very tough staw to begin with. the straw is almost green on the bottom with the grain at 15 %. I was having trouble getting it through our 9500 last year. I can see us upgrading our round baler to net wrap in the near future to help with baling. Thanks for the replies.