Tandem placement and turning radius

That's my wife. And thanks.

 

No one is talking about damage.

Imagine looking down on the truck from above.
If the fifth wheel is forward, it is closer to the steer axle, so it will "follow" the steer tires in their turn more closely, than if the fifth wheel was slid farther back.
It really isn't a lot of difference. But, if you are driving a trailer that does not have sliding tandems, like a tanker, then if may be worth it for that one corner you always seem to just catch the curb on.

Most of the more experienced drivers I have worked with in the past usually only slide the fifth wheel to get their steer axle at the weight they "feel comfortable with".

 

Want an easy way to understand how tandem placement affects turning radius???

Go grab the end of a 20 foot 2×4, let the other end drag on the ground. Now walk around objects while dragging the board. Pretend like you are a truck and the board is the trailer, the dragging end of the board is like where your tandems contact the ground. Watch how far apart your foot prints are from the drag mark of the board.

After going around a few objects, go cut the board down to 10 feet (simulates sliding your tandems as close to the front of the trailer as possible) and drag the board around the exact same course as you did whenbit was 20 foot. Walk exactly where you walked the first time. The drag mark will be much closer to your foot prints with the shorter board (tandems all the way forward).

Tandems all the way forward minimizes turning radius, but maximizes tail swing.

Tandems all the way back maximizes turning radius, while minimizing tail swing.

NOTE: Tail swing is NOT demonstrated in the board experiment.

 

You are completely right on everything, I just wanted to highlight this last point.

One of the things I try and hammer into my guys is that if you don't HAVE to be 90 degrees to the trailer - DON'T BE.

Unfortunately, hauling dry vans there are an increasing number of places where we have to. Some of them are old buildings laid out for COEs and 48 foot trailers. More are newer facilities that are designed to give drivers the bare minimum space to work. That would be fine if the facility was being used as designed, but they end up parking trailers in between dock doors or along the curb across the way. Even in those places, sliding your 5th wheel to get more space is generally a fruitless endeavor.

In my 11 years of driving, there have only been 2 occasions where sliding the 5th wheel to create space was necessary.

The first was at a John Deere cross dock. I was told to drop in spot 12 in the lot across the street. It was a narrow spot with not a lot of space to work with in the aisle. I got the trailer in the hole and just needed to jockey the tractor in front when I realized that while I had 4 inches of clearance on both sides up front I wasn't going to clear all the way back. Can't get the tractor around unless I back all the way in and I can't back out on the street without a couple guys to stop traffic, so I walked across to get a yard jockey to reposition one of the two trailers. After explaining the situation yard jockey said "sounds like a you problem" and drove off.

Doing it again I would have raised Cain until I got some help, but I was prideful and impatient to start heading home. I put the 5th wheel all the way back and the tandems all the way forward. Wiggled the tractor 90 degrees to the trailer while keeping the trailer set 3 feet off the dropped units and then eased myself around. It was so tight I had to get out on the passenger side to GOAL. It was dumb, but I got it done.

The other time US Express managed to get a fire hydrant in between his landing gear and his tractor. I don't know how, but I needed to get him out so I could do my thing. Those extra couple of inches made the difference.

 

Me too ...maybe you can tell me how to slide my trailer axles so I can turn shorter ..also do I need to slide all 3 axles or just 1 or 2 of them ???