Why is it better to have the tandems slid forward when alleydocking?

When inserting the trailer into docking spot at an angle, the point of least clearance to the obstacle on the inside of the turn happens when the trailer tandems pass that obstacle. That significantly changes how far forward you tractor is at the point based on trailer wheelbase. That's why it takes less space to get in a spot with the tandems forward. You are effectively backing a shorter trailer.

However, depending on the angle at which the trailer enters the spot, you are also effectively backing a much wider trailer because of the tailswing. If the docking spot is so narrow that the trailer has to be straight as it enters the front of the spot, one loses most of the benefit of having the tandems slide forward, as the overall trailer length, not the trailer wheelbase, determines how far forward the tractor is at that point.

However, even in those situations, having the tandems forward can require less space in front of the truck, because the shorter wheelbase trailer reacts much faster if one needs to pull up to make a correction.

 

I was going to try and properly explain it but now I'll just say.

Ditto to what he said.

 

Y’all fell for it again

 

Completely unrelated to tailswing or anything else but just a reminder: if you're backing into a dock that has a steep slope that comes down from a flat lot, keep the tandems forward until after you get down the hill so you don't destroy the side skirts if your trailer has them.

 

I was honestly expecting more obtusiveness like previous threads. Glad to not get it.

 

Tandem placement and turning radius

 

Lol had no clue. Fool me once blah blah blah