What is it that makes short trailers difficult to back?

[Peter417]

A couple decades ago I got my first towing experience with a skinny little PWC trailer. It was extremely difficult to back but both my wife and I got good at it. Any other trailer is a breeze including my caravel. This bring us to my question. What is it that makes a trailer more or less difficult to back. Is it the distance form the ball to the trailer axle? Does width play a part? So maybe the distance from the ball to the wheel? Do dual axles make a difference?

[Peter417]

This shows how a short vs long trailer react but there is not discussion of what other factors might come into play.

https://www.youtube.com/watch?v=PhE-n_zyUmU

[Peter417]

and to take my thread off topic, competitive trailer backing is a thing somewhere...

https://www.youtube.com/watch?v=MN_AxxHFRU0

[BayouBiker]

The neat video shows how geometry impacts backing. Geometry makes the short trailers more sensitive to changes in steering angle and as importantly how the angular accelleration multiplies much faster.

Width and number of axles alter resistance to angular acceleration ( rate of change in direction of the trailer) so larger trailers with multiple axles are also less sensitive to minor mistakes.

[GCinSC2]

Time for VW to get er done!

https://m.youtube.com/watch?v=IOXlZbAfcdo

[Bill M.]

Pretty much it is the ratio of the turning radius of the TV and the length from tongue to the axle of the trailer. Somewhat affected by the absolute length of the trailer.

[Jim J]

In the diagram, R is the distance from the tongue to the axle.

L is the distance your tow vehicle pushes the ball to the right
( or the left).

Theta is the angle your trailer moves through from your starting position to your ending position.


From Geometry, L = R x Theta in Radians

or Theta = L/R

Shorter trailers have smaller R so angle is high for movement L compared to a longer trailer with a bigger R.

[ROBERT CROSS]

KISS....The closer the trailer wheels are to the pivot point the quicker it reacts.🤓
So...the slower you go makes it feel longer.

Bob
🇺🇸

[GetawA-S]

Peter417,
Competitive caravan backing is actually a thing...
When I was a kid, the farmers knew such of the hay workers would be able to back a farm trailer into the barn. (I was not one of them.) The front wheels turn with the tongue, and the rear wheels are about 15 feet further back.
And yes, there were competitions at the county fair...
Backing a travel trailer is a cinch by comparison!

[Peter417]

Originally Posted by GetawA-S

Peter417,
Competitive caravan backing is actually a thing...
When I was a kid, the farmers knew such of the hay workers would be able to back a farm trailer into the barn. (I was not one of them.) The front wheels turn with the tongue, and the rear wheels are about 15 feet further back.
And yes, there were competitions at the county fair...
Backing a travel trailer is a cinch by comparison!

I almost brought that up in my first post. I have backed one of those a bit as well. I did it with zero precision with the super H but it was close enough. That one definitely takes some practice.

[OTRA15]

. . . similar to striking a wooden match on a surface to get the tip to ignite . . .

Short match . . . quick flick . . . not so easy with a long match . . .

[richw46]

I have backed up various trailers since I learned to drive more than 60 years ago. In the 70s I worked for UPS and got a chance to attend a tractor trailer driving course. I drove a Mack 5 speed cab pulling a (about) 55' trailer from Louisville to Cincinnati and back. When I got back to the yard the instructor told me to back it up to the loading dock. I put that thing square in the hole. He said "lucky, take it around the building and do it again", so I did, put it right back in there.

I have to say that it was pretty easy. Like others have said, the shorter the distance between the steering axle and the trailer wheels, the more sensitive it becomes. It was no big deal to put that trailer where I wanted it to go.

[OTRA15]

Well said, Rich.

I remember in college watching a big semi make a delivery next to the cafeteria, early in the morning during a snow storm. He had to back in from the street and make a number of minor turns to get lined up to back into the dock. Obviously he had done this many times before, as he covered the 50 yards or so without a correction, and was going probably 5-10 MPH the whole time -- in the dark . . in a snow storm.

Yes the driveway was well-lighted, but still . . .

When he got out of the cab, he noticed this young dumb-founded college freshman staring at him . . . and just nodded with a slight smile on his face.



. . . as if to say . . . "no prob" . . .

[Silvr_Bullet]

Actually a smaller trailer is easier to get in position to back into a campsite. What’s the secret? If it’s not working on the first or subsequent tries..pull up several feet and reposition.... much easier to accomplish this maneuver than a comparatively longer trailer. Now some will know the full story

[Kim06]

Things to remember:

Yes, shorter trailers do react quicker to steering input than do longer trailers. (A 55' trailer is easier to back that a 28')

Proper setup for the back is very important. If you do a proper setup the trailer will practically park itself.

I cannot say this loudly enough. Before you back, get out and look (GOAL) at where you are and where you are going.

If at any time you are unsure. STOP and GOAL. Pull up and reposition if necessary.

Back slowly, take your time.

When you turn the steering wheel of your TV use small increments and wait for the trailer to react. Do NOT oversteer. Patience is a virtue.

Spotters are important, but....Trust your instincts and GOAL.

[DavidsonOverlander]

Originally Posted by GetawA-S

Peter417,
When I was a kid, the farmers knew such of the hay workers would be able to back a farm trailer into the barn. (I was not one of them.) The front wheels turn with the tongue, and the rear wheels are about 15 feet further back.
And yes, there were competitions at the county fair...
Backing a travel trailer is a cinch by comparison!

That is how I learned to back up a trailer. Growing up on a farm I had to be able to back up wagons with a tongue that turned the front wheels, and implements with a single axle. The actions you take are the opposite when it comes to steering. The real fun was backing up the baler with a hay wagon behind. As an added challenge our hay wagons were older and had a fair bit of play in the linkages between the tongue and wheels. The hardest thing to reverse was a small utility trailer that had a distance of about 7' from hitch to axle. In my early teens I jackknifed it and broke the tongue. I still have the axle from that trailer. It's from a 1932 Dodge that was one of my family's first cars. I'm hoping to find someone who can use it in a restoration.

[DavidsonOverlander]

Originally Posted by richw46

I have backed up various trailers since I learned to drive more than 60 years ago. In the 70s I worked for UPS and got a chance to attend a tractor trailer driving course. I drove a Mack 5 speed cab pulling a (about) 55' trailer from Louisville to Cincinnati and back. When I got back to the yard the instructor told me to back it up to the loading dock. I put that thing square in the hole. He said "lucky, take it around the building and do it again", so I did, put it right back in there.

I have to say that it was pretty easy. Like others have said, the shorter the distance between the steering axle and the trailer wheels, the more sensitive it becomes. It was no big deal to put that trailer where I wanted it to go.

So this makes me wonder as I've never driven a fifth wheel or a tractor trailer. Does it make it easier or harder to reverse having the hitch above the rear wheels?

[richw46]

Originally Posted by DavidsonOverlander

So this makes me wonder as I've never driven a fifth wheel or a tractor trailer. Does it make it easier or harder to reverse having the hitch above the rear wheels?

I have not pulled a 5th wheel but I can tell you that backing that 55' trailer was a breeze compared to the boat and cargo trailers. I was in my mid-30s had never driven a tractor-trailer before that day and had no problem at all putting it into the loading dock. It's the distance between the trailer wheels and the tractor (tow vehicle) wheels that make the difference. Location of the hitch/5th wheel made no difference to me.

After driving for UPS for 8 years I learned to backup using only the side mirrors and not looking over my shoulder. I can put my 17' Ranger bass boat into my garage with a few cars parked on the street and 2 cars parked in my driveway. I've skewered the beer fridge a couple of times because I forgot to put the motor down. Otherwise, piece-o-cake.

[richw46]

Originally Posted by Kim06

Things to remember:
(snip, snip)
I cannot say this loudly enough. Before you back, get out and look (GOAL) at where you are and where you are going.
Spotters are important, but....Trust your instincts and GOAL.

Excellent advice. I'd like to add...LOOK UP! In many of these campgrounds you're going to be parking near a tree. Low hanging limbs can put nasty dents in the end cap. Same for going into a gas station with an overhang. Know your clearance, Clarence.

[jcanavera]

Originally Posted by Peter417

A couple decades ago I got my first towing experience with a skinny little PWC trailer. It was extremely difficult to back but both my wife and I got good at it. Any other trailer is a breeze including my caravel. This bring us to my question. What is it that makes a trailer more or less difficult to back. Is it the distance form the ball to the trailer axle? Does width play a part? So maybe the distance from the ball to the wheel? Do dual axles make a difference?

It is the distance. I’ve not noticed the tandem axles being consequential but as my trailers have gotten longer over the years, and living in the same home, I’ve had to adjust my pivot points as to when as to when I start turning to negotiate backing into my driveway.

Jack