gayler
Well-known member
How do you decide on the length of the tongue to make a trailer easy to back?
Trailer tongue length question
- Thread starter gayler
- Start date
paranoid56
Well-known member
math. 
zmotorsports
ALLIANCE MEMBER
I generally take the width of the tow vehicle, divide in half and add between 6 and 10 inches.
This is for a general utility type flatbed trailer.
Mike.
This is for a general utility type flatbed trailer.
Mike.
There's really no easy or hard, simply what you get used to. Short is as easy as long (now I know people are going to disagree with that) but here's why I say that. I have pulled everything from 53 foot semi trailers to 28 foot semi trailers to a full trailer(AKA hay wagon) with a short tongue, and there wasn't one of those that I could not go backwards with with my foot to the floor, and all of them in high range reverse as well (yes, even the truck and trailer) and with SOME throttle in reverse in high range. My brother drove one too said you can't do it, I proved him wrong behind Malarkey roofing in Portland, there was lots of room back there and nobody around. I'm not going to tell you that was in a straight line, because it was all over the place at that speed. I pulled those for over 10 years and it became easy for me at some point. Shorter length means smaller faster movements with the steering wheel, and once your brain learns it, it's there, there's really no difference.
Thanks guys. I am building a small utility trailer from a small boat trail and angle iron from a old fuel tank stand. The original tongue was eight feet long. So far all I have in it is the price of the welding wire. Some of my welds still look like boogers, but it's getting better.
j-guenth
Well-known member
You need tongue weight to make the trailer tow straight. You should be able to find from the local trailer supplier. Measure the trailers that the supplier has.
zmotorsports
ALLIANCE MEMBER
Exactly. This is why I also use the pivot style tongue jacks that pivot up parallel with the trailer so the tailgate will lower without coming in contact with anything. That is enough to ruin your day.
Mike.
A little longer tongue will be easier to back and will tow better, If you keep in mind that yes you do need enough tongue weight. The extra length will also let you jack knife tighter when trying to get into tight places. Just what I do for my own trailers. 42 yrs in the trucking business.
I'm no expert but have towed a few trailers in my time. You want to tongue length long enough so you can turn sharp with out the body of the trailer taking out the taillights on the tow rig. The longer the distance from the ball to the axle will give you a less responsive trailer to steering inputs while backing. To me this is a good thing. To short and the trailer wants to turn real fast and backing is harder, especially if the trailer is small and hard to see. Then there is the distance from the tow rig axle to the hitch, the wheel base of the tow rig, and the turning radius of the tow rig.
lg
no neat sig line
lg
no neat sig line
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koditten
Well-known member
Larry uses the same formula I do.
You want the best answer? Put another axle under it.
You want the best answer? Put another axle under it.
kerrynzl
Well-known member
math.
1.5 x the overall width should be the distance from the axle centreline to the Towball centre.
[or wheelbase centre to the Towball centre on a tandem]
Overall width is determined at the outer edge of the tyre sidewall.
On a tandem there is another calculation also to be considered
4.6 x the wheelbase should be the distance from the wheelbase centreline to the Towball centre
So if you start using "spread axles" you'll need to go longer
These are minimum lengths for a good handling trailer, a good handling trailer is easy to back up
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It's not just the tongue length, but the distance from the axle to the coupler. Long length, like a boat trailer, reacts slower to steering input and is easier to back up. Short trailers react quicker and tend to jackknife easily. A longer tongue, as measured from coupler to the front of the bed, will keep you from hitting your tow vehicle when backing up.
kerrynzl
Well-known member
An 8' wide single axle trailer needs the towball centre to be 12' from the axle centreline MINIMUM
If the 10' deck 60/40 [meaning 6' in front of the axle] the tongue should be 6' long
If the 10' deck 50/50 the tongue should be 7' long
12' measurement is impossible on a 40' trailer but it certainly exceeds the 1.5 minimum
On a single axle trailer all you need to consider is the 3 load points [the towball and the 2 tyre footprints]
All these formulas were calculated on a skidpad years ago for an engineering student's project.
kerrynzl
Well-known member
kerrynzl
Well-known member
In your example the numbers are correct.
Normally an 8' wide trailer has a 6'6" wide deck [9" each side for fenders] and 13'-14' in deck length
A normal 10' deck trailer is 10 x5 which has a 6'6" overall width
do the math on these and it makes sense
If somebody builds a wide trailer with a stupid short deck the tongue will need [or appear] to be longer.
The trailer only cares about the 3 load points
I built a car hauler trailer for a friend that only wanted a 12' deck instead of our standard 16' deck [[thinking it would save $$]
The widths are the same, and his trailer ended up only 2' shorter overall [rear overhang]
The front 1/2 of the deck was also shortened 2' making the tongue look ridiculously long. [ a tool box remedied that ]
On a side note: the shorter trailer didn't save any $$$ .
We still had to buy the same amount of steel [we just ended up with more waste]
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