Need some design help

[Gary_in_Indiana]

<font color=blue>"I wouldn't go too overboard"</font color=blue>

I'll try to figure out what the greatest length I might need would be and then add a foot. /w3tcompact/icons/smile.gif I'm guessing that total shouldn't exceed 9' from the upright to the kingpin and would more likely be 8' or less. Is that a doable length for the 4 x 4 x 1/4 square tubing?

 

[Anonymous Poster]

9 feet is more than doable with 4" square, but 9 feet is going to be pretty long on a single X city tractor, and may be a tad short on something with an air tag triple.
You could make the piece from the kingpin to the drop adjustable by setting up the top of the verticle like a Reese hitch with a pin to lock the actual toung length. Only thing you'd have to worry about would be a driver leaving it too far back and punching it thru the windshield of the chase car.
Going that route would also be of benefit when towing the dolly with the chase car. as long as you put a boom crutch at the back of the dolly.