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Your fifth wheel’s king pin is the single easiest way for a thief to drive off with your rig — a standard hitch can latch onto it in seconds. The right lock makes that connection physically impossible, and the best ones are heavy enough that cutting them off is a noisy, time-consuming job. This guide cuts through the options to the locks that actually fit a standard 2-inch king pin and hold up to years of use.
I’m Min Islam — the founder and writer behind Trending Car. This guide is built by comparing the manufacturers’ published specifications and the patterns across verified customer reviews, so you get each pick’s real strengths and trade-offs instead of marketing spin.
You park at a campsite overnight or store your trailer for months, and a dependable fifth wheel king pin lock is the difference between confidence and a bad morning.
Our Picks at a Glance
How To Choose The Best Fifth Wheel King Pin Lock
A king pin lock slides over the exposed coupling pin on your trailer’s nose. When it’s engaged, a thief’s hitch cannot physically connect to your fifth wheel, so your rig simply cannot be towed away. The choice depends on how much cutting, prying, and picking effort you want to force.
Weight and material are your first line of defense
Heavier locks made from forged or cast steel are dramatically harder to cut through with bolt cutters or pry off with a crowbar. A 10-pound block of steel is a different deterrence level than a 2.5-pound aluminum shell — the weight itself is the security.
The locking mechanism affects your daily routine
Some locks use a simple key that turns a bolt, others use a sliding bolt you push into place, and premium designs use a push-and-lock system. If you hook and unhook weekly, choose a mechanism that is easy to operate one-handed. A lock that is annoying to use is a lock you will stop using.
Quick Comparison
| Model | Best For | Material | Weight | Lock Type | Amazon |
|---|---|---|---|---|---|
| Heavy-Duty King Pin Lock★ Best Overall | Best Overall | Alloy Steel | 1.9 kg | Key Lock | Amazon |
| VULCAN Forged SteelTop Performer | Commercial Trailers | Alloy Steel | 2.5 lb | Sliding Bolt | Amazon |
| United Pacific 90100Best Value | Cold Weather | Cast Steel | — | Key Lock | Amazon |
| Reese Towpower 63251 | Quick On/Off | T6 Aluminum | Light | Key Lock | Amazon |
| Husky 38790 | Fits Adapter Plates | Steel | 2.8 lb | Key Lock | Amazon |
| Equipment Lock | High Visibility | Alloy Steel | — | Barrel Key | Amazon |
| Trimax TFW80HD | Lifetime Warranty | Steel | 3.39 lb | Push Button | Amazon |
| WAR-LOK TKP-10 | Dropped Trailers | Cast Steel | 5.044 lb | Rotating Disk | Amazon |
| AMPLock LPCVR | Maximum Security | Cast Iron & Steel | 10 lb | Push-and-Lock | Amazon |
In‑Depth Reviews
1. Heavy-Duty King Pin Lock
Our pick — over 4.5★ from 250+ verified ratings; the strongest balance of quality and price.
The bright yellow deterrent that makes thieves move on to an easier target.
This Jayour lock wraps your king pin in top-quality durable steel so a thief’s hitch cannot mate with your fifth wheel. Buyers report it “does a job no issues whatsoever” after four months of steady use, and the 1.9 kg weight gives it that solid, reassuring heft in your hand.
The built-in handle makes it genuinely convenient to carry, and the high-visibility yellow warning tag does double duty — it reminds you the hitch is locked and signals to would-be thieves that the pin is secured. What wins people over is the functionality: owners consistently find it easy to put on and take off, and it fits tightly enough that cutting it off would take serious effort.
The steel is painted rather than powder coated, so it is built for function over show. Several owners note it is simply the best king-pin lock they have owned, and the build quality earns nearly as much praise as the function itself.
hefty deterrent
- Heavy 1.9 kg solid steel construction feels tough in the hand
- Bright yellow tag is an obvious visual deterrent
- Easy on and off, no fiddling with the mechanism
bulky handling
- Painted finish may show wear sooner than powder coat
- Weight adds bulk to carry around
grab it if: you want a proven, heavy steel lock that is easy to use every single day.
think twice if: you want a powder-coated finish that shrugs off the elements for a decade.
2. VULCAN Heavy Duty Forged Steel King Pin Lock
The forged-steel cover that still looks brand new two years later.
VULCAN builds this lock for serious protection — the heavy-duty forged steel covers the entire king pin, making it impossible for a trailer to connect while engaged. Owners who have used it for years report it “still looks brand new even 2 years later,” a durability record that speaks to the powder coat finish.
The 2.5-pound sliding bolt lock comes with two keys, an orange powder coat that resists the elements, and a bright orange ribbon so you do not bump your head on the hitch. It is engineered for tamper resistance and works on commercial semi trailers as well as RVs — several owners lock up Class 8 trailers with it.
One honest note: the key insertion can take a few attempts in some units, and if you buy two, the keys may not be matched between them. The durability is the thing everyone raves about, and the visual deterrent is strong enough that thieves will look elsewhere before they start.
forged strength: the forged steel construction holds up to years of weather and use without visible wear.
tight fit: key alignment can be finicky at first, so practice the motion before you are in a hurry.
3. United Pacific 90100 King Pin Lock
The cold-weather champion that stays freeze-proof when you need to open up.
United Pacific’s cast steel lock is built for the 2-inch diameter kingpin, measuring about 3 inches tall with a 2.88-inch inner measurement so it covers the entire pin. Buyers in freezing Michigan conditions specifically praise it: the key works easily even in bitter cold, and the well-painted surface protects the lock from the elements so you won’t have freeze-up issues when you need to open up.
What wins people over is the ease of use — owners say the key slides smoothly in and out and it attaches and locks in place without any fuss. It works on 48-foot Great Dane flatbed semi trailers and Reese Revolution king pins alike, and the full coverage means you won’t get grease on your clothes if you bump into it.
The cast steel construction is durable and the blue finish is genuinely well painted. For the price, this is a heavy, dependable lock that one owner called “pretty idiot proof to use.”
reach for: you park in cold climates and need a lock that refuses to bind up in winter.
look elsewhere if: you want a flashy deterrent — this one is about solid function over show.
4. Reese Towpower 63251 King Pin Lock
The feather-light lock you will actually use every time you park.
Reese builds this lock from durable extruded T6 tempered aluminum, which makes it noticeably lighter than the steel options — and that is exactly the point. Owners use it daily at campgrounds and at home because it is so simple to put on and take off, fitting perfectly on a 2019 Sabre without any struggle.
The bright yellow design is a visible theft deterrent, and the all-weather easy-grip ends make handling comfortable in any conditions. A dust cap helps seal out the elements, and it includes 2 keys. The ease of use and functionality both earn top praise — it is a lock you trust when you leave the campsite.
The honest trade-off is that aluminum is lighter than steel, so a determined thief with heavy tools might cut through it faster than a forged steel block. Owners frame it as a deterrent that motivates a thief to move to the next target, not an impenetrable vault. For low-priced confidence on a whim thief, it delivers.
choose this: casual campers who value easy on-and-off over maximum cutting resistance.
avoid if: you park unattended for long stretches and want the heaviest steel available.
5. Husky 38790 Fifth Wheel Lock
The U-bracket lock that clears adapter plates without any fitting issues.
Husky’s design is beautifully simple: slide the U-bracket into the grooved portion of the king pin and insert the lock pin. Owners with a Pullrite Superglide hitch confirm it works great even with the adapter plate installed, with no fitting issues and plenty of clearance — a compatibility win that many bulkier locks cannot match.
The 2.8-pound steel construction is sturdy and well made, and the design makes it virtually impossible to get bolt cutters in to cut the lock. Owners note removal without the key would be “very difficult, noisy and time consuming,” which is exactly the deterrence you want. It fits standard fifth wheel hitches with ease.
The recurring theme in owner feedback is that this is a “nice heavy duty simple lock” that would make a lot of noise to remove. It is easy to install, fits perfect, and the solid construction means your trailer stays put — one owner notes they installed it a month ago and still have their RV.
adapter friendly: clears Superglide and other capture plates that block bulkier locks.
simple lock: the basic U-bracket approach is easy to use and hard to defeat for a quick thief.
6. Equipment Lock 5th Wheel Kingpin Lock
The signature red lock that tells crooks to keep moving to an easier target.
Equipment Lock covers your trailer’s 2-inch kingpin with a high-security barrel lock system, making it impossible for anyone to hitch to it and drive away. The signature red finish is powder coated for durability, and the steel-locking structure is built to withstand thousands of pounds of force.
It ships with 2 keys and a nice “install” flag you attach to the lock so it warns you the lock is engaged. There is no mounting required — just slide it onto the kingpin, secure it with the key, and you are done. Owners mention it is easy on and off and works great right from the start.
One buyer switched from a large steel pin lock that was too wide for their new pin, and this one fit fine. The high visibility is the standout feature — the bright red finish is meant to tell crooks to move on before they even start.
buy this: a powder-coated finish that resists weather and a bright deterrent color.
pass on it if: you want the absolute heaviest steel — this prioritizes finish and ease over sheer mass.
7. Trimax TFW80HD 5th Wheel King Pin Lock
The 3.39-pound push-button lock so heavy you will dent whatever it lands on.
Trimax’s full collar design does two jobs at once: it prevents grease transfer to your hands and adds an extra layer of security by covering the whole pin. The rugged weatherproof epoxy powder coat delivers superior rust and corrosion resistance, backed by a limited lifetime warranty.
The easy push-button locking mechanism makes setup quick and low-maintenance, and the ultra-tough steel withstands tampering and harsh environments. Owners praise the solid construction and smooth locking action, and the weight — 3.39 pounds — makes it a formidable visual deterrent. One buyer with a Pullrite hitch worried about the capture plate, but it fit fine.
The 2 keys work smoothly, the bright red finish is unmistakable, and the heavy-duty build gives owners confidence that no one is getting it off. Watch your feet during install — if you drop it, whatever it lands on is getting dented. The locking mechanism gets mixed reviews from a small minority, but the durability and ease of use dominate the feedback.
high visibility
- Full collar design keeps grease off your hands
- Epoxy powder coat resists rust and corrosion
- Limited lifetime warranty backs the build
pricey option
- Heavy enough to dent whatever it drops on
- Locking action is smooth for most, finicky for a few
grab if: owners who want a rust-proof, lifetime-warranted lock that is quick to engage each day.
skip if: you need the lightest possible lock to carry around — this one has real heft.
8. WAR-LOK TKP-10 King Pin Lock
The 5.044-pound cast steel cone that deflects a thief tractor’s fifth wheel plate.
WAR-LOK designed this lock specifically for dropped and untethered trailers, protecting expensive cargo from a would-be thief tractor. The conical shape deflects the fifth wheel plate of a thief tractor, so even if they try to ram up to your pin, the geometry works against them.
The cast steel exterior is nearly impenetrable, and the rotating disk lock technology makes it almost impossible to pick. It comes with a convenient handle and weighs in at 5.044 pounds — serious heft that tells anyone looking that this trailer is secured. It fits the king pin snugly without removing the lube plate in many cases.
Lost keys can be replaced if you register with the manufacturer, and owners who have had it for years call it “nothing cheap or cheesy.” The main fit note is that some autoslider hitches require removing the second plate, so check your setup. Owners emphasize any lock is a deterrent, not a guarantee — but this one makes defeat a very noisy, very long project.
tamper proof: the cast steel cone and rotating disk lock make picking and cutting a serious challenge.
hitch check: autoslider setups may need the second plate removed for a snug fit.
9. AMPLock LPCVR King Pin Lock
The 10-pound beast that makes cutting, drilling, or prying a wasted afternoon.
AMPLock’s conical anti-traction pin design prevents theft using chains or modified hitches, and the 10-pound weight acts as a powerful deterrent to cutting, drilling, and forced entry. Crafted from ductile cast iron and heat-treated steel, it resists rust, tampering, and harsh elements year-round.
The patented push-and-lock mechanism installs in seconds — no mounting, just push and it locks. It fits with a Teflon plate installed, which is a compatibility win for many RVs. The special high-security keys are replaceable through the manufacturer, and owners who bought third AMPLock products keep coming back for the superior protection.
The build quality is what everyone raves about — owners call it a “big ‘ol hunka metal,” well-made, and the only brand they would purchase. One owner noted the grey coating is chip-free after use, and the weight alone deters unprepared thieves. This is the lock you buy when you want maximum security and do not mind the bulk.
reach for: maximum anti-theft protection where weight is not a concern and you want the heaviest deterrent available.
avoid if: you want a lightweight daily-use lock — at 10 lbs, this is a commitment to carry.
Understanding the Specs
Weight and Material
The single biggest security factor is how much steel is between a thief and your pin. A 2.5-pound lock is a mild deterrent; a 10-pound cast iron block forces hours of noisy, tool-heavy work. Forged and cast steel resist cutting far better than aluminum, which trades weight for easier handling.
Locking Mechanism
Key locks are the classic choice and work fine for most. Sliding bolt locks add a manual motion you control. Push-button and push-and-lock designs are the fastest to engage — ideal if you hook up weekly. A mechanism that is annoying to use will get skipped, which defeats the whole purpose.
FAQ
Will a king pin lock fit my 2-inch king pin?
Do I need to remove the lube plate for the lock to fit?
Will the lock work with a Pullrite Superglide hitch?
How long does a king pin lock last?
Can a thief cut through a king pin lock?
Will the lock freeze up in cold weather?
Do all king pin locks come with keys?
What is the difference between a key lock and a push-button lock?
Final Thoughts: The Verdict
If you want one dependable pick, the fifth wheel king pin lock winner is the Heavy-Duty King Pin Lock because it pairs heavy-duty alloy steel with a bright yellow deterrent and easy daily use at a fair price. If you want a lock that shrugs off cold weather and stays freeze-proof, grab the United Pacific 90100. And for maximum anti-theft protection where weight is no concern, the AMPLock LPCVR at 10 pounds is the one to reach for — the crowd favorite among owners who demand the heaviest steel available.
How We Picked
We do not accept paid placement. Every pick is matched to a real buyer and a real use-case; we do not hands-on test units.
Sources & Methodology
Specifications: manufacturer listings and product documentation. Review insights: verified customer reviews, as of August 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.
As an Amazon Associate, Trending Car earns from qualifying purchases. This does not affect which products we feature.