By on June 28, 2019

best trailer locks

From time to time, TTAC will highlight automotive products we think may be of interest to our community. Plus, posts like this help to keep the lights on around here. Learn more about how this works.

Yes, I know it seems we got our pithy phrase backwards in the title. What we mean by it is that after loading your trailer, you should lock the thing, geddit? We’ll be here all week folks; try the veal.

It doesn’t matter what’s in the tow behind — boxes of tools, camping equipment, or a Hemi ‘Cuda — it all makes a tempting target for the criminal element. This goes for actual camping trailers, too. A retailer near your author’s hometown has to deal with loss prevention more often than anyone would care to admit. After all, in most cases, the theft is as simple as a hitch-up-and-go.

In the same way The Club steering-wheel lock is used to simply provide a deterrent, rather than making your ride theft-proof, so do these hitch locks for trailers. If there are two units side by each, a thief will likely make off with the one that provides the least resistance to an easy payday. A person should still lock the doors on the thing or, if it’s a flat deck, find some other way to secure the valuables.

Meaning, of course, that none of these are a total waste of money. Something is always better than nothing and we waded through a few different options so you don’t have to.

(Editor’s note: As noted above, this post is meant to both help you be an informed shopper for automotive products but also to pay for our ‘90s sedan shopping habits operating expenses. Some of you don’t find these posts fun, but they help pay for Junkyard Finds, Rare Rides, Piston Slaps, and whatever else. Thanks for reading.)

The Best Trailer Locks

1. Editor’s Pick: REESE Towpower Universal Coupler Lock

reese towpower universal coupler lock

This is the editor’s pick because it’s the one your author uses on his own trailer. No, it isn’t the most expensive on our list of the best trailer locks and any determined thief can defeat the thing with two quick zips of an angle grinder. It is, however, a great deterrent and easy to use. Its universal fit is good for many different hitch sizes.

A c-clamp style locking mechanism slides down over the hitch’s top while a spherical insert goes plugged into the business end of your trailer’s tongue. Push to lock, no key required. It does come with a pair of keys to unlock the thing, though. Personal experience has taught your author that the c-clamp will rub against the trailer hitch, scraping off the paint and causing some surface rust. It’s not a critical issue but is unsightly

Pros: Affordable, easy-to-use, aluminium body and steel bar

Cons: Could be easily defeated by a determined thief

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2. Highly Reviewed: Master Lock Trailer Hitch Lock (377KA)

master lock trailer hitch lock

Based on a heady 700+ reviews, this thing from Master Lock is the clear popularity king in the school of trailer locks (trailer locks, hard knocks, … no? Fine.) This unit is chrome plated and only weighs a couple of pounds. Unlike the lock shown above, this one fits into the trailer tongue in a horizontal fashion, making for a less intrusive look and avoiding paint rub.

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It fits many different hitch sizes and allegedly will resist rust and corrosion when exposed to bad weather. Turning the key allows the shackle to slide toward the coupler, foiling anyone who’s trying to make off with your tow behind. Master Lock is also a very recognizable brand name, which never hurts.

Pros: Lightweight, horizontal installation

Cons: Blingy style may attract attention which is what one is trying to avoid

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3. Great Coverage: Master Lock Universal Hitch Lock (379ATPY)

master lock universal trailer hitch lock

Also from the boffins at Master Lock, this unit is installed similar to the Reese lock at the beginning of this post but also included a vertical shield that rests ahead of the trailer coupler. Given that the shield acts on a ratchet and is integral to the lock’s success, it may fail more easily under the duress of a determined crook and a pry bar, especially when compared to the other Master Lock shown above.

Grey and charcoal coloring makes this guy almost invisible on the trailer tongue and would certainly be tough to see at night when a ne’er-do-well might be casing the joint. The flaw in its stealthy appearance is a bold white sticker announcing its brand name.

Pros: Tough to see, good brand name

Cons: Needless brand name advertising

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4. Trimax Premium Universal “Solid Hardened Steel” Trailer Lock

trimax umax100 premium universal trailer lock

Anything with “solid hardened steel” in its title description earns this gearhead’s notice. One size should fit most couplers and, unlike others here, there is a cover for the keyhole to keep out debris and other nonsense that can scupper the lock’s use.

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It is of the same design as your author’s Reese unit, which is to say it deploys a twin ratchet system that passes vertically through two parts of the lock. The body of the thing is painted an appropriate black, while the ratchet loop portion that swings over top of the coupling is chrome color. This means it’ll likely wear off some of the hitch’s paint over time. Keep a spray bomb handy.

Pros: Cheap insurance, stealthy appearance

Cons: Certainly not the cheapest one here

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5. AMPLOCK Boat Trailer, Trailer and RV Coupler

amplock u-brp2 coupler lock

This 10-pound monster is costly but reviews seem to indicate that it may be worth the cash. Unlike others in this list of the best trailer locks, it wraps around the hitch ball, leaving the top of it exposed but certainly not enough on which to place a hitch and drive away with the trailer. Its seller alleges the lock is ‘molded to fit’ and, to a degree, they have a point.

How? Well, most other locks are able to fit a variety of ball sizes. This one is good for a 2-inch only, meaning its snugs itself against the coupler with no slack. That’s a common knock against some other locks which can be loose even when secured a tightly as possible. That slack gives thieves an opportunity. It would appear that is not the case with this AmpLock. It also means you’ll need to order the specific size for your trailer.

Pros: Snug fit, not painted bright yellow

Cons: Bloody expensive

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6. Master Lock Universal Coupler 389DAT Lock

master lock coupler trailer lock

You guys and girls know that I’m a sucker for anything painted a bright color, even when it shouldn’t be. Trailer definitely fall into that category, as logic dictates it’s definitely better not to advertise the fact you’ve got a trailer worth stealing. Other than color, it’s also basically identical to another Master Lock earlier in our list. But this is my post and I’m including it.

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The business end of this lock goes pushed into the trailer’s coupler at which time the bid (red) shield is ratcheted forward to engage the whole works. It is a featherweight two pounds and is reasonably priced. Nearly 90 percent of customers gave it a four or five star review. A universal design means it will fit the vast majority of popular hitch sizes.

Pros: Good price, great reviews, it’s red

Cons: Ratchet style engagement, it’s red

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7. Tow Ready “Gorilla Guard” Coupler

tow ready gorilla guard coupler lock

Gorilla Tape is pretty good, but what about Gorilla Guard? The tape doesn’t matter, as it may share a name but is not made by the same company. What we can tell you is that this lock is built to protect a 2-inch ball, meaning it won’t have the wobble and shake of some universal units. Its design means it won’t fit all couplings, however, with the widest it’ll accept being a width of 3-13/16 inches and a height of 5/16 of an inch. It would not fit my trailer, for example.

For those of whom it will, this is not a bad option. Made of heavy duty material, this lock slides horizontally onto a trailer ball to scupper unauthorized hitching of an unattended trailer. One customer reports they were forced to leave their boat trailer on the street overnight. Upon inspection, it was revealed someone tried to hammer off the lock but was unsuccessful in doing so. That’s a pretty reassuring anecdote.

Pros: Tough enough to stand up to a hammer attack, slim design

Cons: That slim design means it won’t fit all trailers

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8. CURT Powder-Coated Aluminum Trailer Tongue Lock

curt aluminum trailer tongue lock

Powder coating usually shows up on exhaust parts and chassis frames, not trailer locks. Nevertheless, here it is, blasted onto a uniquely shaped lock made of aluminium sold by a recognized brand name that sells a ton of other trailer gear. This lock is good for 2- and 2 5/16- inch couplers, so it won’t shake loose on the common two-incher.

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Sliding horizontally onto the trailer tongue, this lock prevents thieves from backing their tow vehicle up to your trailer’s hitching point and making off like a buncha bandits. By blocking off the portion of the tongue into which the truck’s hitch ball is placed (yay for double entendres!), it provides a good deterrent against the night shift looking for a five-finger discount.

Pros: You’ll be the only one at the campground with a powder coated lock

Cons: A surprising amount of bling

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Notes on Trailer Locks and Trailering in General: It’s always good advice to park an unattended trailer in a well-lit area or in a locked place where the thing can be checked on frequently. No anti-theft device is perfect, of course, and all the manufacturers on this list have plenty of fine print about not being ultimately responsible for the loss of your toys.

ALSO SEE: A Step Up: Best Running Boards for Trucks

When you park your trailer, chocking the wheels is an another excellent idea to avoid unexpected calamity. If it has brakes, after all, they’re only activated by the truck and not on their own. A runaway trailer is no fun. Some owners take it to the extreme and affix a parking enforcement boot to one of the trailer wheels but that just makes it look like it lives in the city of Chicago (Ed. note — hey! (and yes, you can buy parking boots on Amazon)). That’s probably the best takeaway out of all this, in fact.

Stay alert, stay safe!


[Images provided by the manufacturer, lead image: Nattapon B/Shutterstock]

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10 Comments on “Load & Lock: Best Trailer Locks...”

  • avatar

    I have #6 on a waverunner trailer. So far, so good.

    It’s also in a locked storage yard, but a lot of people have access. I also have a cable lock on each wheel, and when the waverunner is on it, another cable lock around the waverunner attaching it to the trailer.

  • avatar

    The first picture wants me to point out a pet peeve of mine. Can people please remove the ball mounts from the receiver of their hitch when not in use? They are removable for a reason. Keep them in the cab until use. Especially that monstrosity pictured above.

  • avatar

    From personal experience (actually preventing a trailer theft,) lock types 5, 7 and 8 are highly effective by fully preventing a thief from getting their hitch ball into the trailer tongue AND preventing itself from being easily removed by a thief. Making so the key only opens a port where a custom wrench then withdraws the locking rod such as was used by that much older hitch lock made it impossible for the family trailer to pull a disappearing act behind a thief’s truck (had quite the boot print on it too, showing just how frustrated the prospective thief was at finding his easy mark stymied by a 5-pound hunk of metal.)

    The others in this posting may be good to stop casual thieves but the harder they have to work to get it off, the more likely you are to still have it sitting where you parked it in the morning.

  • avatar

    I’ll have to see what the lock picking lawyer thinks before buying any of these. IIRC he got through the first one in a matter of seconds.

  • avatar
    Art Vandelay

    That picture hurts my shins

  • avatar

    Locking the tongue and/or ball are good, and combined make it a pain in the ass to try and steal your trailer.

    Put a boot on the trailer tire and anyone not specifically targeting YOUR trailer for specific contents will go find an easier target, because that’s even MORE work.

    (And if someone’s specifically targeting you, you have bigger problems than passive security can easily solve.)

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