Backing 48' fixed spread axle trailer in tight spots

Indeed if you're turning around yes that's a half circle so 180 degrees in rotation, you are correct.

We were referring to the geometry of a truck with the fifth wheel being the pivot point. So the truck being in a straight line would be 180 degrees, turned around like you say would be 360 degrees or 0 degrees it's the same thing minus a rotation really.

 

Look; you are over thinking this. The truck going in a straight line is zero degrees. Any deviation; start your counting....10, 20, 45 degree whatever.

 

I think I can explain this easier.

Think of 360 like the 12hr clock.

If 360 is the same as 12 oclock, then 180 would be the same as 6 oclock. He is correct.. you would be facing the opposite direction.

When I was 16 the mall cops threatened to have me arrested if I didnt leave for practicing 180's in the parking lot.

Lets face facts... we were never meant to be engineers.

Hurst

 

Starting off at zero degrees yes but that would mean you're driving a straight truck. The key word is pivot point being the fifth wheel. Axis or whatever math term is used.

I'm overthinking this sure but I've got the image of a protractor in my head and 0 degrees is both arms pointed the same direction and 180 is fully extended in a straight line.

To hell with this math stuff anyway it's Saturday!
Dang it drivers, I can just picture us all sitting around the horseshoe in a truck stop arguing over geometry. That poor waitress lmao

 

I could see this arguement while BBQ'ing, beer and confused wive's who already know the answers, just not sure what exactly we are debating over and know better than to correct loud men while consuming adult beverages. LOL

Hurst

 

A few more posts and this will be thread of the year. Or at least argument of the year.

 

Your trainers statement "you just got to figure it out" is probably the best advice as far as a fixed spread goes.

 

Then you are 'confidently' wrong.

 

The trailer as it relates to the truck is at zero degrees when you are in a straight line. As you begin to back and the trailer begins to turn, so begins the change of relationship between the tractor and the trailer, and it happens in degrees. It isn't rocket science. This is basic stuff here. It begins with being 1 degree and if you could literally back it all the way around over the space your truck occupies it would be 360 degrees.

 

Okay take the shades off @Rock 'n Roll Relocater - no one claimed this was rocket science.
Since you wanna get complicated lets do it. See if you can keep up.

We agree firstly that a tractor perpindicular to a trailer is 90 degrees but if it were perpindicular to the opposite side it would be 270 degrees. See how that works?

Now perfectly in the middle of those two perpindicular points is STRAIGHT.
Perfectly in the middle of those two numbers is 180 degrees.

Back to the clock, 1200 is 0 degrees. Both hands (tractor and trailer) pointed in the same direction. Straight up.
Move the hands around to 1159. This is a called a circle. 360 degrees. This position also has both hands straight up. A position a semi cannot physically be in.

0600 on the clock. Both hands are pointed away from each other. Holy #### does it kind of look like a straight line now? Oh my god it does! That's 180 degrees.