Tandem placement and turning radius

I didn't understand Bill's explanation.

Are you calling the drive wheels "the tandem" here? I know that the dictionary definition of tandems just means two things that work together, but I've never seen or heard anyone call the drive wheels the tandem before. Every other time I've seen or heard tandem in my career, people were referring to the trailer wheels. That's why I have to ask.

 

Ok, if Hammer166 won't explain what he meant when he said that "A 5th wheel centered above the drives means the kingpin moves with the tandem", can someone else explain it please? Even though I've never heard or read anyone refer to the drives as a "tandem" (or "tandems"), I think that Hammer166 means that "A 5th wheel centered above the drives means the kingpin moves with the drives", but I don't know for sure. First of all, Hammer166 refers to the drive wheels as the "drives" in the same sentence. So if Hammer166 calls the drive wheels the "drives", I am hesitant to think that tandems refers to drives since he refers to the drives as the drives. Secondly, the kingpin is always above the drives because the kingpin is connected to the trailer. When Hammer166 says "a kingpin centered above the drives", I am guessing that he means "a kingpin centered more towards the front of the semi-truck than the drives", but I am not 100% sure.

What does Hammer166 mean?

I always strive to make myself crystal clear. For example, look at my post #128. I went to the trouble of drawing a picture to explain my definition of a "tighter turn" and a "tighter turning radius". I wish everyone else would strive to be clear as well.

 

Let me translate this for any new drivers or anyone else who does not understand Hammer166.

A 5th wheel centered directly above the drives means the kingpin moves with the drives. But if the 5th wheel is forward of the drives, the rotation of the tractor moves the kingpin towards the inside of the turn sooner. One would think this means more off-tracking, but because the 5th wheel is forward of the drives, the kingpin follows a longer arc than the drives, effectively reducing off-track. That's why I said I thought moving the 5th wheel with the intent of changing the cornering behavior wasn't a productive endeavor.

P.S. Hammer166, did I translate this correctly?