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Side-Door Bar Lock Assembly - 55" Long

Side-Door Bar Lock Assembly - 55" Long

Item # 3057-55
Our Price: $62.73
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Trailer Door Latch
Shipping Weight: 9 lbs
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Polar Hardware Latches - 3057-55
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Cam-door style lock is ideal for use on trailer side doors that may be smaller than rear doors. Features 55" long pipe and rust- and corrosion-resistant zinc coating. Great Prices for the best trailer door latch from Polar Hardware. Side-Door Bar Lock Assembly - 55" Long part number 3057-55 can be ordered online at or call 1-800-940-8924 for expert service.
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Polar Hardware Trailer Door Latch - 3057-55

  • Cam Door Latch
  • Latches
  • 55 Inch Long
  • Lock Not Included
  • Polar Hardware

Cam-door style lock is ideal for use on trailer side doors that may be smaller than rear doors. Features 55" long pipe and rust- and corrosion-resistant zinc coating.


  • Cam-door style lock is ideal for use on trailer side doors that may be smaller than rear doors
  • Rust- and corrosion-resistant zinc coating
  • Mounting hardware not included
  • Overall pipe length: 55"


3057-55 55" Long Side-Door Bar Lock Assembly

Video of Side-Door Bar Lock Assembly - 55" Long

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Polar Side-Door Bar Lock Assembly Review and Installation

Hi there, trailer owners. Today, we're going to be taking a look at Polar's side-door lock assembly. These are available in three different sizes. You can get it at 36, 45 or 55 inches long. And just like the name says, this is a locking door latch assembly. It is mostly used for the side for your smaller doors, but on some of your enclosed trailers, you may have similar styles like this at the back as well.

We just got done replacing one that was originally on this trailer that had rusted off and our nice new one is holding it nice and tight. We've got considerably more pressure. So our door's not vibrating around as much as it used to. We'll be replacing the one on the other side here as well. But we wanted to give you a comparison of how your old ones might look.And with this old style here, you can see it's all rusted up, squeaks a lot.

It's kind of difficult to move. And on the other side, well, that one, the handle came completely off. Our new one's going to be nice, smooth, and easy to operate, simply unlatch it. It also offered more pressure than our other one did, which keeps our door closed. Previously, when we had both latches shut before our handle broke off, this door would kind of rattle around.

It really didn't stay very well shut with even just the new one on the one side, it's significantly stronger and feels more secure and shut. It offers a steel construction. So it's going to be solid and durable and to prevent rust and corrosion like our old one's had. It has a zinc plating on it, which is going to keep all that moisture off and give us a nice finish over it that's going to last a long time and they're also a fairly standard size.When we replace this one, our bar here was able to line right back up with the existing holes. It doesn't come with hardware, so you will need to reuse your old hardware or purchase new hardware if you want it to be nice and shiny.

I do highly recommend carriage bolts if you are replacing the hardware so that way it has a nice button look appearance. And when you go to tighten down the nut on the other side, it's being held out here. It also comes with a new lock side for your handle. It's got a nice, smooth pivot and holes in both the top and bottom. So you can put a padlock through when you've got it all latched and closed so nobody can get inside. It's a pretty straightforward and simple installation.In most cases, you won't have to do any drilling, but sometimes you will if there's a slight difference on yours. We're going to go ahead and show you how to install it now. One of the things you might consider, if you've got a enclosed trailer that you want to keep out, any moisture and stuff, maybe like a side door on a toy hauler or something. You may want to put some silicone or seal it on the backside of this to keep out any moisture. So you can see why we're going to be replacing our old one here. Rust has got the better of it. We're going to go ahead and take our old assembly off here and put a whole new assembly on. It doesn't come with new hardware so we will be reusing our old bolts and they come as a quantity of one.So we're going to go ahead and get two of them and replace both sides. That way we'll have a matching look here at the back of our trailer. And we don't have to worry about this happening to the other side as well. We're now here on the inside of our trailer, where we can see our hardware here. On some of your trailers you may have a trim piece here that you need to remove. Ours doesn't have any kind of enclosure on it, covering it up. And we're just going to remove these carriage bolts. There's a nut on that we're going to take off on each one and we're going to use a 1/2 inch socket to do so.And then we can just slide it off of here. And it's not a bad idea just to clean up the area behind where your old ones were, we're just using a little bit of alcohol to clean it up, but you could use soap and water and a brush, just like you clean your car. We can now take our new one and put it in place. We want to make sure that the hinge here is on the outside and we're going to just take our carriage bolt, slide it through and then slide it through here. You want to make sure that you're using carriage bolts because you see the holes here are cut out in a square. That way you don't have to hold it while you're tightening it down. And just put a few turns on it, you don't need to go crazy. It's just going to make, installing the rest of our hardware a lot easier if we don't have to hold it up.From here, we can just install the rest of our bolts by lining up the holes again and reinstalling the hardware. We can then go back and tighten our bolts down. So we're just going to take these off on the backside. Ours are nuts that have Torx bit openings in them, and we're going to use a T55 Torx for ours, but yours could potentially be something else. Now, the assembly might get a little stuck in there, that's no big deal. We can just knock it through with our hammer and an easy way to ensure you don't damage the threads. Now I know this is an old one, so we're not going to be reusing it anyway. We can thread our nuts on there, and that usually is enough to help us tap it, just to kind of get it started.We can likely now just go to the other side and pull the assembly office. We've made a little gap between the door and the latch assembly. So now we can easily just kind of work it out. If you have a lot of rust and stuff on here, sometimes it's easier to use an abrasive pad to remove the material rather than some alcohol on a cloth. So now we've got our new latch assembly and I went ahead and checked it with our old one and unfortunately our bolt holes aren't going to line up on this one. So we are going to have to drill a new hole for our new latch. So an easy way to ensure that it's going to line up properly we're just going to put it on our bar, push it in place.And then we're going to try to use one of the old holes as a template if we can. Looks like it's going to line up pretty good with that bottom hole. So since it's going to line up with our bottom hole, just fine, we're going to go ahead and use that bottom hole. Then we'll just set this thing up straight after running it through and use the top hole as a template. So I've gone ahead and just slid the bolt in. I didn't tighten it down yet. We're just using it again as a template. So we're going to line this up right below our other hole. And then we're going to go ahead and make a little pilot mark.We can move our bracket out of the way, and then just finish drilling this out. We're using a 5/16 drill bit. Once you get your top field out, we're just going to put that back in place. You don't want to put your lock assembly on it and slide your carriage bolt through. And we're going to walk around to the other side, to install our nuts onto our bolts. Here on the other side, we're just going to start our nuts, trying to be careful not to push the hardware back through. And then we can just tighten them back down.Now that we've got it tightened down and installed, let's go make sure that it's going to work properly. We've got a good tension on our door it's going to hold it shut, and our latch works properly. And you might be wondering what we're going to do about this hole here. And you've got a couple of options. You could run a nut in a bolt through it, but it looks like that's going to interfere with our latch mechanism. So we're just going to be filling it up with some silicone. You can get black silicone here at if you think you're going to need some. And we're just going to seal that up. You can also fill in the inside if you want to ensure that you're completely sealed. And that completes our look at the Polar side-door bar lock assemblies.

Customer Satisfaction Score:

Customer Reviews

Side-Door Bar Lock Assembly - 55" Long - 3057-55

Average Customer Rating:  4.8 out of 5 stars   (171 Customer Reviews)

Cam-door style lock is ideal for use on trailer side doors that may be smaller than rear doors. Features 55" long pipe and rust- and corrosion-resistant zinc coating.


Wow! Side door bar lock assembly arrived in great condition and much faster than I anticipated. I’m very happy with the build quality and high service level from etrailer. I highly recommend them.

Chris B.


Excellent quality. Still looks and works like new!


Well, be honest, I am not real happy with it. I think the mechanism inside comes loose the remote quit working after a couple of months I am unhappy with it, but it does lock my trailer.


Overall a good product. I installed it over an RV style door on my enclosed trailer.

Cheap stamping of the latch itself and lack of quality control leaves me needing to dremel out the opening to correct the alignment of the hole so that a puck style lock can be used. A little disappointed here...


The product was delayed a few months because of the manufacturer, however Etrailer continued to send me updates through Email letting me know the status of my order. I never felt like I was left hanging. When the product finally did arrive It was well packaged and just what I ordered. I then recieved a follow up Email making sure it was what I ordered and delivered in good condition. I will continue to do business with Etrailer because of their excellent customer service and my trust in the products they sell.


The service we received was excellent. Our Bar Locks arrived much faster than expected and were exactly as described. They were installed easily and a perfect fit. The only problem is now the shiny new bars don't match the rest of the rusty trailer.


Not quite the same as the original. It does work. Mounting holes need to be enlarged.


Etrailer were the only people that had the rod length I need, and the assemblies came exactly as described. Order was also shipped swiftly, and I really appreciate it.


Great quality, and a fair price. Shipping is always a detriment these days. Still, it's exactly what I've been needing to secure my instruments. Clearly Etrailer, is seeking repeat customers with there heads up on back orders, and follow up E-mail.
Thanks, Bob L.


Product came very quickly. I had two barn doors on a dump trailer that I wanted more support for closing, so I used this instead of a clasp. There is pressure pushing out from inside, and this keeps it solidly closed. Also having the long handle gives a little more leverage to push up and allow it to open with the pressure against it. I would definitely recommend this product to someone looking for a longer, more secure door latch.


I like it! An excellent mechanism and easy install. I needed six 5/16 × 2 1/2" carriage bolts for my installation. I did use nylock nuts, but that is probably overkill. And I cut and drilled a metal backer plate for the inside of the door because it is hollow core.

In my installation, my door surface is slightly raised. I had to rebend the movable locking arm to accomodate the thickness. I anticipated this when I ordered the bar lock and it was straight forward with bending tools- not everyone will want to try this and it is not needed on a flush fitting door.

I installed the bar lock over my existing flush key latch, for additional security.

The attached pictures show the trailer/door before the install, and the door with bar lock after install.


This was also used on our custom landscape truck to keep ramp door shut.


Still looks and works great.


Fantastic hardware at an affordable price. Quality product. We have ordered 11 of these latches to weld onto a converted shipping container - turned storage units. We anticipate doing a bunch more orders of the same.

Very friendly staff that is quick to respond. Shipping was quicker than anticipated.


The quality of the product is excellent. It really surpassed my expectations by far.


Perfect fit, took minutes to install


Website was fairly simple to navigate. Placed the order and recieved the product within a few days. Installation was simple and it appears to work great at this time.


Great product and just what I needed at a great price. Highly recommended. Thanks


Excellent communication and fast shippi ng


Receive promptly in great condition. Looked just like the pictures. Thank you


Changed a front dropdown hybrid camper tent door from screw clamps to these normal door latches for better sealing.
Not quite as heavy metal as older latches, but adequate for task and thick enough to weld. Robot welding is beautiful, some spatter berries to remove. Plastic cover plugs on ends were distorted damaged and ugly so I tossed those. Overall good rpoduct and worked well for intended purpose. Good price for the quality received.

Kevin J.


Replaced screw clamp latches on front of a fold out camper with these cam locks. Better seal and more secure. I had to cut and weld to get length I wanted but overall worked well. Still rust free. Needs some oil on hinges occasionally, as to be expected. Would buy again if needed.


Works Great! Had to modify the mounting holes a bit, nothing I couldn't handle. Would be nice to have a bolt hole to bolt hole drawing on the website, along with the total length.


I purchased this enclosed trailer lock system to use on my tool storage shed after being broken into. This thing is great. It has secured my shed and the way it mounts, they'd have to tear the shed down in order to get into it. The parts arrived on time, they were complete and I've been using it for a year. I live in rainy country and there are no signs of rust or aging at all. Great part and great value.

Steve H.


I love this lock system. I put it on a tool shed to prevent theft. It’s tough and smooth and easy to use. I live in the Pacific Northwest and it is holding up remarkably to our wet weather. Not a spec of rust anywhere.


Perfect. Exactly what I needed. Fantastic Price too


Everything about the transaction was great!! But when the package arrived the UPS driver wanted to make sure everything was there that I ordered. The box was a lot bigger than needed and the whole end was broken open to the place I could pull my parts out through it without using a knife. If there had been any smaller parts in the box they would have been gone. Just thought I’d let you know. But everything was there. Thank you!!


No issues with the product. I did however weld a piece of metal over the latch so thieves can't break it and gain entry, as well as rounded off bolts with a double nut on the interior. I also purchased a big box lock that goes with a solid pin. Without that it only takes a good pry to pop the latch and break in. etrailer has been great to do business with

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