If you’re the proud owner of a travel trailer, you know that security is a top concern. After all, trailers are uniquely one of the most expensive assets that you can invest in that someone else can easily just tow away against your will.
When your trailer is unhitched and unattended, the number one defense you’ll have against would-be crooks will be a heavy duty coupler lock. So if you’re looking for the best trailer lock on the market to protect your little home on wheels, look no further- here’s five reasons you need to buy this Proven Industries lock right now.
This post may contain affiliate links. If you make a purchase through them, we may receive a small commission, for which we are extremely grateful, at no extra cost to you.

Verdict of the Proven Industries Trailer Lock
I go full-blown lock nerd in this article, so if you’re not into the nitty gritty details of pin tumbler locks and key bittings, the TLDR of this article is that this Proven Industries coupler lock is seriously the best trailer lock you can get on the market.
It uses the most secure type of lock core and is designed (both on how it fits around the lock and its materials) in a manner that makes it super challenging to break into.
Still need more convincing? Let’s get into it.
What is a coupler lock?
If you’re a newbie RVer and still getting a hang of all the confusing jargon, no worries- I’ve totally been there!
A coupler is the connection point, mounted on the tongue of the trailer, that connects your trailer to your vehicle. Usually, the tow hitch on the back of your vehicle will have a trailer ball- to attach the trailer to the vehicle, the coupler has a ball receptacle that receives the trailer ball (if talking about receiving balls makes you giggle, buckle up- this post is full of ‘em! Also, we should totally be friends).
Coupler locks are generally designed to fit over the ball receptacle in some way when your trailer is not connected to your vehicle (like, say if you need to go grocery shopping or want to go for a hike and are leaving your trailer at the campsite) and prevent ne’er do-wells from simply attaching their vehicle to your trailer and hauling it away.
I know someone whose (might I add, VERY expensive) trailer was stolen from a parking lot. It turns out she had left it parked in the lot without a coupler lock- so this piece of metal may be the very thing that prevents your beloved trailer from getting stolen!
What should I consider when buying a trailer lock?
There are few key (pun intended!) elements of a trailer lock that you should consider when making your purchase. It may initially feel silly to spend so much time- and money- worrying about these issues, but at the end of the day, your couple hundreds of dollars of investment into a solid lock may prevent the theft of your much pricier investment- your trailer.
That said, here are things to consider when a choosing a coupler lock, broken down by lock core, material, and design:
Lock Core:
“Pin tumblers”, “wafer tumblers”, “disc detainers”- without getting too technical, there’s a multitude of different lock “cores” (the innermost part of the lock that receives the key) a manufacturer can choose to use in their locks. And these different types of cores accept an even wider array of oddly shaped keys.
Considering the variety, it’s no surprise that this is the most widely overlooked and misunderstood feature when trailer owners are considering a new lock.
The long and short of it- disc detainer cores are king, and that’s exactly what you’ll find in the Proven Industries coupler lock if you order on Amazon (but more on that below).
Many of the most popular and affordable locks on the market (I’m looking at you, Master Lock) use what’s called a pin tumbler core. This ubiquitous mechanism, found in most residential locks, is cheap to manufacture, but generally speaking, requires the lowest skill and least equipment for a would-be thief to pick, jiggle, or rake open without having a key.
Many affordable pin tumbler and wafer tumbler locks use shorter or less complex keys that, in turn, require less pins or wafers (the internal mechanisms that allow the lock to open) in the lock core. Simply put, the more pins/wafers/discs that a lock has, the harder it is to pick.
And, while many locks found on the shelves of the big-box stores look beefy and formidable, all the “hardened steel” and similar security buzzwords found on their packaging are pointless if the lock can be easily opened with a $20 tool found on Amazon.
To make matters worse, some of the cheaper locks don’t even have unique keys, meaning that anyone can go out and purchase a similar model lock and literally have the exact key to use on your lock! In summary, the lock industry is plagued with complacent design, and thieves know it, even if you don’t!
Lock Material:
Who would bother with picking a lock if it’s easy to just simply smack or cut off from your trailer? Lots of locks that are on the cheaper side are made of lightweight aluminum or even plastic that are easy to pry off with a crowbar, cut off with bolt cutters, or simply smash off with a hammer.
You’ll also want to select a lock with materials that will hold up over time and in a variety of weather conditions, like ones that are made with stainless or hardened steel cylinders and brass lock cores.
Lock design:
The actual design of your lock and how it fits around the coupler directly impacts how effective it is at protecting your trailer.
For example, one of the most popular lock designs is U-shaped, where a crossbar is locked into place in the ball receptacle with a U-shaped shackle. Despite their popularity, these locks are pretty simple to break into, given how easily a pry bar can be slipped between the U-shaped shackle and the coupler and then snapped off with just a little leverage.
The very best locks will fit snugly around the ball receptacle on all sides without any leeway for someone to slip a crowbar into.
Why the Proven Industries lock is the best Trailer Lock
Now that I have lapsed into Lock Theory 101, let’s chat about why I’m the hypewoman here to preach that the Proven Industries Model 2178 is the best trailer lock out there.
Oh, let me count the ways!
1. Your key is unique and the locking mechanism is sophisticated.
Beyond just the key for this lock being unique, the key pairs with the aforementioned disc detainer type core, if you buy through Amazon or specifically call Proven Industries directly and ask for a disc detainer model. This style of lock requires expert skill and specialty tools to pick, and would-be thieves can’t even make a copy of your key at a hardware store.
Note that if you buy directly through Proven Industries website (as opposed to buying through Amazon), the standard Model 2178 will come with a tubular lock core. These types of locks are regarded by industry experts as a less secure mechanism than a disc detainer one, given available tools that have made picking tubular locks quite simple. As such, we’d strongly recommend picking one up from Amazon or if you prefer, calling Proven Industries directly.
2. The only way you’d be able to pick the lock would be literally lying underneath the trailer.
The lock core is designed to face the ground, meaning you’ll insert the key to unlock it from the bottom of the puck.
While it may initially take some uncoordinated folks (hi, that’s me!) a bit of practice to negotiate with this key placement when using the lock, it also means that, if someone were going to attempt to pick it, they’d literally have to lie on the ground, crane their neck upwards, and try to make dextrous hand movements with their arms awkwardly extended upwards to do so.
While this doesn’t inherently make this lock bulletproof by any means, it would be MUCH harder to pick than a lock core positioned on the side or on the top of a coupler lock (which is how the majority of them are designed!).
3. The trailer lock itself is surrounded by one-quarter inch thick hardened steel plate (about 6.3 pounds of steel!).
Moving on to the materials, the lock is covered by extremely thick hardened steel that could withstand some seriously determined thieves, with drills, hammers, crowbars- I’ve even watched a YouTube video where someone takes a sledgehammer to it for minutes with no success! It’s like a little tank on your trailer’s tongue!
4. Given the design of the Proven Industries trailer lock, it would be virtually impossible to pry it off.
Beyond its hardcore materials, the Proven Industries Lock is designed to basically act like a tight sheath that slips around and fits snuggly against your ball receptacle. There simply isn’t wiggle room to slip in a crow bar or bolt cutters and somehow pry the lock off.
5. The safety chains are coiled up and actually contained within the lock itself.
A lock isn’t going to do you much good if a thief can simply attach your trailer’s safety chains to their bumper and just drive away (an unnervingly ingenuous trick among thieves).
So one of my favorite features of the Proven Industries lock is that it’s the only lock design I’ve seen that actually incorporates and protects your safety chains. While you’re using the lock, you’ll coil up the safety chains and tuck them inside the body of the lock, making it impossible for anyone to access them.
Pretty cool, huh?
Drawbacks to the Proven Industries Trailer Lock
Now, of course, nothing is perfect, so I wanted to point out some slightly less awesome things about this trailer lock.
1. Price point.
No ifs, ands, or buts about it, the Proven Industries lock is a lot pricier than many other options on the market, retailing for around $250 (whereas many of the locks you can buy at Home Depot are in the $30-$50 ballpark).
In my opinion, though, you 100% get what you pay for– i.e., a lock that will serve as a formidable opponent (and deterrent) to even the most determined crook and, you know, doesn’t provide the same key to every single other person that buys the lock. Given how much I spent on my trailer and the aforementioned tale of the stolen rig, I (a self-proclaimed cheapskate) have absolutely no problem shelling out that kind of money to give my trailer better protection, and me, some peace of mind.
2. It’s not universal.
This one’s nitpicky, but if you’re going to buy this lock (which you totally should!), be sure that it’ll work with your trailer and that you’re buying the right size.
First of all, you’ll need to make sure you buy the right size- there’s the lock for 2-inch couplers (this is the most common size of coupler for trailers). Alternatively, if you have a heavier trailer, you may have a 2 5/16-inch couplers, which would, thus, need a corresponding bigger lock.
Model 2178
(for 2-inch couplers)
Model 2516
(for 2 & 5/16-inch couplers)
While these two sizes account for the vast majority of travel trailers on the market, make sure to confirm what size your coupler is before making the leap!
Additionally, these locks only work with certain types of couplers. The 2-inch lock only works with A-frame, U-haul, tie-down engineering, and trigger-latch couplers, whereas the 2 5/16 one only works with A-frame or adjustable couplers. While these are generally the most common types of couplers, if you happen to have some other kind, this lock won’t work for you.
There you have it- 5 reasons why Proven Industries is producing the best trailer lock on the market. Do you have any questions about the lock or how it works? Let me know in the comments below!
Thank you for reading our post! Check out our latest stories here and follow us on Instagram (@UprootedTraveler), YouTube, or on Facebook to see what we’re up to next!
What if they just take the bolts off the coupler, remote it and the lock, and pop on another one?
Hi Josh,
Thanks for reading!
Most crimes are ones of convenience, so, given that removing and replacing the coupler would be a fairly time consuming task (much more so than, say, breaking off a cheap lock with a crowbar), it’s pretty unlikely that someone would attempt that. If you’re particularly worried about it or live in a high-crime area, you could always get the bolts tack welded to the frame.
Best,
Jess
While 90% of Amazon’s 700+ reviews are five stars, there’s also a “frequently returned item” warning. From the comments, the main issue is ordering the wrong size, but then returning without issue. So, that’s good.
Hi John,
Thanks for reading and yes, I think you’re exactly right. For what it’s worth, we anecdotally know dozens of RV owners that own the Proven Industries lock and have never met anyone who hasn’t been satisfied with it.
Happy RVing!
Jess