How to build a Self Lifting Trailer Tailgate 15

How to build a spring assisted trailer tailgate made from an old leaf spring and some scrap steel. Read more to see how we did it!

This post was originally created in Dec of 2013. I just went in (Jan 2019) and updated the whole post with more research, a parts list, better descriptions, and two videos! Hope you enjoy.

Story & Research

My FIL has been working on rebuilding this old trailer. He built a nice fold down gate on it, but it ended up being too heavy for anybody other than him or myself to lift.

We looked at some coil springs like they put on the big heavy equipment gooseneck ramps, but it seemed complicated to setup and the springs we found were way too heavy duty. Then I remembered seeing some small utility type U-haul trailers with leafsprings mounted underneath that were attached to the gate with a shackle.

After some research I was able to figure out that they are actually ‘motorcycle hauling’ trailers from U-haul. Here is a good video from U-haul with the spring loaded gate so you can see it in action:

Building our own assisted tailgate

Now it was time for us to build our own. We started by drawing some pictures and dug through my random offroad parts bin. When the project was initially finished, the spring held so well that the (really heavy) gate didn’t even touch the ground when we let go. We added some washers above the spring on the brackets and now it just lightly comes to a rest on the ground when you let go.

Underneath. You can see where there was a crossmember added then what used to be two u-bolt plates used to capture the leaf spring. The washers between the spring in the plate were used to adjust the tension on the gate, because at first the gate wouldn't lower all the way to the ground on its own.
Underneath. You can see where there was a crossmember added then what used to be two u-bolt plates used to capture the leaf spring. The washers between the spring in the plate were used to adjust the tension on the gate, because at first the gate wouldn’t lower all the way to the ground on its own.

Safety warning

PLEASE be careful if attempting this project. Obviously standard precautions need to be made when welding/grinding but in this particular case I am talking about stored energy. Springs by nature have A LOT of energy when they get stretched/compressed/bent depending on what kind of spring they are.

In our example today we are using a leaf spring which when bent contain enormous amounts of energy (the same energy used to lift your trailer tailgate) so please be careful and stay out of harms way from the spring and any other hinge/pinch points.

Parts needed

Here is an approximate parts list assuming you already have a welder, grinder, and the associated safety equipment. Your needs will vary based on the weight and length of your gate, and the setup of the tail of the trailer and gate crossmembers.

One leaf spring with bushing (the one in the pics was a primary leaf spring from the rear of a ~2000’s Chevy S10). The most common automotive width is 2.5″ wide which is what I used. You could also look into using a trailer leaf spring like the one linked below which is narrower at 1 3/4″ but I can’t say what weight spec you need having not tried that type of spring before.

Two u-bolt plates or ~6″x6″ pieces of 3/16″ or thicker pieces of flat plate. Just make sure they are wide enough for the spring you selected. Typical automotive leaf springs are 2.5″ wide (Fords are usually 3″ wide) and trailer type leaf springs are typically 1.75″ wide.

Four heavy duty bolts (1/2″ or larger with washers and locknuts)

Some extra steel for creating a crossmember (if needed) and reinforcing the top gate mounted bushing

Shackle material this can either be an actual spring shackle from a junkyard vehicle (probably the same one you got the leaf spring from), or a ‘shackle lift kit’ from Amazon like the one below. If you want to make it yourself, you can find a ~2ft long section of 2″ wide by 3/16″ or 1/4″ thick steel strap then cut to length and drill the holes you need.

More pics of the self lifting tailgate

Up position
Up position
View from the rear. The spring assembly really doesn't take up very much room on its own.
View from the rear. The spring assembly really doesn’t take up very much room on its own.

The beauty here is that both bushings came from a single leaf spring. We simply cut the leaf spring into several pieces with a grinder and cutoff wheel. One consists of the part we used for the spring (about 2/3 of the leafspring). The other consists of a short section from the other side with the bushing and ~1-3″ of spring to be welded to the gate (any leftover length is just scrap).

The top plate welds to a crossmember under the trailer, then the spring will get sandwiched between the two plates and bolted together. The bushing for the gate will be welded on and reinforced with a small piece of scrap on the top side (you can see in the pic below).

Shackle length – I can’t be prescriptive here, you will need to figure it out for yourself. The U-haul shackle appears to be very short ~5″ or so. The shackle in our example was much longer at about 10″. Therefore there is probably a pretty wide range here depending on the spring you use and how heavy/long your gate is. There will likely need to be some trial and error.

With tailgate in down position. This is my favorite part of this design because unlike the rail mounted springs, there are no wires attached to the tailgate to trip over.
With tailgate in down position. This is my favorite part of this design because unlike the rail mounted springs, there are no wires attached to the tailgate to trip over.

A little ingenuity, some scrap parts, and some hard work made a very useful end product. Between all of our family and friends this trailer gets used almost weekly. Best of all, it is small enough to tow behind my “Honda Hauler”!

Can’t weld? Don’t have the time?

Here are some other options from Amazon that are very solid and install with a couple of bolts:

Option 1

Option 2

Update with user video!

We had a user Nick that posted in the comments below take this article and built a spring assisted gate for his golf cart trailer down in Australia! Thanks for creating this video Nick!

Now you go build something!

Questions? Comments? Tried it yourself and have pics or video? Post below like Nick did!!

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15 thoughts on “How to build a Self Lifting Trailer Tailgate

  • sam

    I’m glad to see this design. It is really awesome. To your point, the other methods do the job, but I don’t like the wiring and certainly don’t like the rattling noise the springs make either during operation or when you’re driving on the road. Your approach is much simpler in design (certainly not easy to do) and looks safer in case of malfunction. If the spring leaf would to snap, then the most likely path would be contained underneath the trailer, while the spring method, the cable could easily swap someone across the face.
    I’m curious as to any drawbacks you have experienced since installing it. For instance, have you had issues with ground clearance? is there a weak point or angle where the spring is not effective either up or down? b

    • Paul Post author

      My family just uses this trailer around the house hauling the garden tractor or whatever else we need to haul at that time. I haven’t really hit any issues with ground clearance yet. When the gate is down the shackle and spring extends approximately 8 to 10″ below the bottom of the trailer which could be a problem for some. The design of this spring system is so robust with automotive parts that I think even if you bottomed out on it from time to time, it wouldn’t hurt it.

      The spring gets less effective as the gate travels up and the spring unloads. I am working off memory here, but don’t remember really encountering any ‘dead’ spots in the springs travel. When we first built it before we adjusted the spring, it was so effective the ramp didn’t even hit the ground.

      This is not necessarily an easy project but does present a good alternative to the two most common methodsof trailer tailgate assist (garage door spring and cable or coil spring on the ramp hinge).

  • Dillon

    I like it! I’m putting together an off road adventure trailer with a flip down tailgate with a spare mounted on it. Looks like this should work for the up assist I’m looking for. Any idea what the weight of your gate is? Do you have a video of it in operation?

  • Josh

    Do you think this could work for fold up stairs on a pool deck? If so can you give me some more detail on parts used and what mods I might need for stairs and deck? Thanks!

    • Paul Post author

      Hmm, that is a good one. I am not sure how well this solution would work for your problem. My tailgate lifting solution uses a single leaf spring from the rear of a pickup/older suv (before they went to independent suspension or linked suspension). Because it is from an automotive application, you would be surprised how much spring tension is packed into a single leaf spring even after it is removed from a pack of leaf springs (most packs have 3-4 springs in them held together with a center pin).

      One idea that might work for you would be the gorilla spring system shown above. That way the spring is contained where it is less likely to pinch/hurt anybody playing around the pool. As long as you had somewhere solid to mount it, you could then attach the lifting cable to the part of the stairs that will be folding up/moving. You could even add some pulleys if you needed to mount it at an angle.

      Hope that helps, good luck!

    • Paul Post author

      Not sure exactly what you mean here, but I will try to explain. The leaf spring ends that we are using do have rubber bushings in them but they aren’t necessarily designed for this much rotation. The bolts through the shackle into the bushings should not be so tight that they try to twist the bushings. There needs to be a little bit of slippage when using factory leaf spring bushings. If they were aftermarket polyurethane bushings then you could tighten the shackle bolts tighter because the sleeve in the bushing can rotate.

      Hope that helps, if not add another comment with some more details and I will try again!

  • Nick

    Saw the pictures. Reproduced idea down in Aussie. On a ride on golf buggy trailer. Posted a youtube video of my build. Acknowledged your info in the summary. Works well.. Nick. Search Ytube for ” trailer ramp assist spring. Using a car single leaf spring. Uses basic parts. “

    • Paul Post author

      Thanks for the post and creating the video Nick!

      I went in and updated my whole post with more notes, research, and your video. I appreciate the contribution!

      • Nick

        Be good to get some measurement specs of the installed parts from a U haul motorbike trailer. Don’t see them in Aussie so far. The pivot links are much shorter. Might experiment with their length to see if any difference in how mine loads up the spring. Nick Tasmania. Thanks for interest in my build..

  • Brandon Mason

    I like it, I work for a landscape company and the one trailer has the gorilla assist on the ramp but still really requires 2 guys for safety to pick it up. I’m gunna show this to my boss cuz this cuts down the amount of strain picking and dropping a ramp all day.

  • Matt Cua

    I knew this post was familiar. It’s just the more updated version with more details. I’ve tried copying this before but It didn’t work out for me. I’m thinking of trying it again.

    • Nick

      A tension adjuster could be added to let the the 2 plates run on a square tube welded on that can slide along square spine. Can slide it in and out .Then pin it at sweet spot with eg a trailer lock pin and clip etc… Adjustable. Would do it it that way if making again. Nick.. Tasmania.My golf trailer setup still going AOK.

  • Afton Jackson

    I like how you did a makeshift assisted tailgate. My son and I are planning to make an improvised one for our pickup truck as well. However, we need a professional to guide us on what products to buy besides the u bolt plates. We could use some help with it.

  • Afton Jackson

    I never knew that the door for a Tailgating Trailer Rental can be used as a ramp as well. We will need help from a trailer owner since we do not have the time to make one. I like that the joint connected is a complicated contraption already.