Delivered this today:

Brand new Gleaner 30' Draper head for an S68 combine:

At delivery, the guy really liked the brand new head cart the head had been setting on, and now had his trade set upon so while I was securing his trade in draper head, he was on the phone purchasing this cart. Told me he wouldn't trust his old cart loaded as far as I'd come, (about 180 miles) so he'll run down with his trade in and bring this one back with him.

That was a bit of a jaunt. The trade in head was also purchased here and delivered there when new. I think the combine was also as the relationship goes back more than the current generation.

I'll ask about the tires as I really don't know either. Have seen the same direction, and opposed several times but never asked. I didn't load the new head going up but I could easily run 40mph with good stability. 43mph and she started to sway, and 50mph was white knuckles time. I loaded the trade in head a bit more forward placing more weight onto the steering axle of the cart and gained about 5mph overall. At 53mph it was really swaying badly but 50mph was easily manageable so that is where I returned at.

Driving up I was kinda laying out in my head a temporary bolt on sway control but not sure how often something like that would be used. Not a lot to it but I don't know how many heads they sell as most are local and the purchasers usually pick them up. I've picked up and delivered several but with exception of this one, it's always been on the gooseneck trailer as a forklift available at both ends for loading, and unloading.

Lengthening the tongue would certainly help as it would place the articulation further rearward. I've done stabilizers on wagons in the past to help with the sway and a couple of good heavy truck steering stabilizers and some minor weldments allowing to pull them very close together in a train type fashion rather expeditiously. One guy tells me this has shortened his transport time with a wagon train considerably. I don't think these folks would allow this to be done citing the amount of usage it would get. 

They won't purchase a DOT rated cart that would go down the road at highway speed as that idea has been pushed several times; I'm told.

I do a lot of oversize loads consistent. Nothing overweight, just oversize. This was easy in the grand scheme so really thought nothing of it. 

Here is an auger I delivered almost to Kentucky from west of Peoria last year. It was 12'4" wide at the outside of the wheels:

I get up to Michigan every now and then on dealer transfer tractors. I'll inquire if they have anything in the works as always have additional room. They would appreciate the cost offset I'm sure.

Here is another Gleaner with the steering tires opposite the drives. I asked the owner as he was dropping it off for service and he tells me the traction is much better, (as Steve noted) than if they match the drives. I meant to ask if he meant with the head elevated, or actually harvesting crops but didn't get the opportunity.