There should be a switch for the two speed.
If you dont know if you have a two speed hydro, I suggest reading your operator manual. After reading your manual if you still dont know, dont worry about going faster.
Fastest I've gone is 24.x MPH in a 2388. It is noticeably different from the ~20MPH top speed that is normal. I wouldn't consider it unsafe, but your steering inputs have to be VERY subtle. I usually keep one hand on the steering wheel, the other on the throttle ready to pull back on it if necessary. The laws of physics are enforced universally.
Putting the machine into neutral while going down hill.... I wouldn't do it. If you do, be sure to put the video on youtube.
The newer McDon swathers flip around and drive down the road in reverse. Certain areas of the country could have combines that go 30 mph and other areas combines are probably going too fast already. We can drive 30 miles on good roads without even seeing a car and other times we are pulling over every 30 seconds so some dork can pass.
I'm going tot go out on a limb and say corn and wheat combines are going to be completely different in the future than they are today. They could be signifcantyly smaller with better ways to seperate grain from trash. Combines might go 8 to 10 mph while bringing in 24 rows at a time. They might kick out bales of stocks for processing into biofuels and 1,000 bu sacks of wheat and corn that can be picked up throughout the year. More focus on getting it harvested and in a safe container and less focus on getting it out of the field that day. Who knows where things are going. . . but faster, bigger, stonger, and more efficient have always led the way. I'm all for safe and fast road hog combines.
I don't want to jump on a side here, but when I see a bunch of !!! and a bunch of not so smiley faces I would agree comments come off a bit lecturous. Combiness does post that way more often than not though so I don't think she ment it as sternly as her comments read.
325mag has the best advice I've seen in this thread...
Farmboy, you have no idea just how far we have already come with this speed technology, already. You are just too young to remember that most combines in the 1960's had road speeds no faster than [some not as fast] as what most big machines harvest with!
It was awesome to see an SPC move 10-12 MPH down a road, 40 some years ago. Now we're cutting every bit of at least half of that! Just 30 years ago, it was still quite amazing to run a 510 at 3 to 3.5 MPH in wheat, not corn. That is just about as fast as the former 21/21A traveled. No, the 21's did not have any such thing as a "road gear." They were 2-speed---slow and slower.
I heard of a guy that had went into overdrive in an older John Deere said it wasn't too bad until the brakes wore out and then he jumped a culvert, went about 20 feet. He said it was the wildest ride he had ever been on, and would never do it again.
I' m willing to bet I'm in the top, oh, 100 here of max combine speeds.
Gonna play it safe.
Last fall when I was having my harvestsmart hydrostatic control freewheel problem on my STS 9860 I hit 58 km/hr freewheeling.
This combine has 1100 45R/46 tires front and 28L26's rear no slop anywhere in the steering.
So I rode it out but 40km I think is about safe max on rear wheel steer units with current wheelbases.
I kinda wanted it to hit 60 but it didn't.
Actually, much sarcasm. I know just how dangerous those free-wheeling stunts are. I've heard of this over and over, throughout the years, but since combines are not the most common vehicles about, I guess it never really hits home, till it happens to you or a close friend.
If I can't get to the field at the standard 19 mph, it isn't worth going there! My old 1480 seemed like it only moved down the road at a snails pace(16mph) compared to the 2188 at 19mph. The 3 extra mph's feels like your going 30!