Trimax King Pin Lock for 5th Wheel Trailers - Collar Style - Hardened Alloy - Yellow

Part Number: TMX56RR

113 Reviews | 6 Questions

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$48.82

Retail:$94.99

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trimax locks king pin lock for 5th wheel trailers - collar style hardened alloy yellow

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Feature Breakdown: Trimax King Pin Lock for 5th Wheel Trailers

How the Trimax King Pin Lock Fits 5th Wheel Trailers

Choosing the Right King Pin Lock For Your Trailer

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Secure your fifth-wheel camper or utility trailer with this heavy-duty, hardened alloy king pin lock. Fits over your trailer's king pin to prevent towaway theft. Full collar keeps your hands grease-free during installation. Fastest Shipping and Great prices for Trimax King Pin Lock for 5th Wheel Trailers - Collar Style - Hardened Alloy - Yellow. Read our customer reviews of Trimax Locks king pin locks. Call 1-800-940-8924 for expert service or order your king pin locks part number TMX56RR by Trimax Locks online at etrailer.com.

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Reviews (113)
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Trimax Locks King Pin Locks - TMX56RR

Features:

Lock secures your 5th-wheel trailer by preventing hookup
Fast, easy, clean installation
- Full collar design keeps your hands clean as you slide lock over king pin
- Push-button lock activates without key needing to be inserted
Yellow color lets would-be thieves know your trailer's locked from a distance
Durable hardened alloy construction
Epoxy powder coat resists corrosion
Tube key lock cylinder provides better security than standard key mechanisms
- Harder to pick and resists drilling
- More difficult to duplicate keys
2 Keys included

Specs:

Application: standard 2" diameter king pins
Overall dimensions: 2-3/4" tall x 4" wide
Inner diameter: 2-7/8"
Limited lifetime warranty

TFW60 Trimax Locks Heavy Duty Solid Alloy 5th Wheel King Pin Lock

Customer Satisfaction Score:

91% were satisfied with this product

9% of customers were not satisfied

etrailer mistake
Wrong item was ordered
Defective

9% of customers were not satisfied

etrailer mistake
Wrong item was ordered
Defective

4.6

113 reviews

5 Stars		(93)
4 Stars		(10)
3 Stars		(1)
2 Stars		(4)
1 Star		(5)

by: Alex 06/07/2026

Does not fit on the king pin of a Curt Rotoflex pin box. Inside diameter is too small to fit of over the upper part of pin.

by: Steve P 07/06/2023

Doesn't fit. Goes on easily over the bottom of the kingpin, but jams when trying to push onto the top of the kingpin. Have to push on fully to activate the lock. It rocks indicating the lock isn't perfectly round as the rock moves with the lock when I rotated to determine why it wouldn't fit. Sanded off the paint on the king pin and inside the lock. Need to pound on and remove with a crowbar. The fifth wheel was standard on my camper. would expect it to fit as they showed in the video's. Have to see about sending back.

Click to Enlarge

Jenny N.

7/10/2023

I am sorry that the lock is not working out for you. Would you be able to send a picture showing how it fits on your king pin.

Steve

7/17/2023

@JennyN Here are pictures of the king pin. The I.D. of the lock is 2 7/8” and the O.D. Of the king pin is 1/64” over 2 7/8” resulting in the pound in pry off. The 5th wheel came with the camper. It is an Artic Dox 27-5.

Jenny N.

7/26/2023

@Steve I reached out to the manufacturer and they agree that it is not working like it should. It should be fitting with your king pin lock. I will have our Customer Service team reach out to you.

by: Brad 08/20/2025

"Heavy Duty Solid Steel 5th Wheel King Pin Lock", not a chance! I put a magnet on the body of the collar, no signs of any steel! Best guess is the body is maybe aluminum. The only steel is the inner cylinder of the keyed lock. Anyone with a hammer could defeat this collared lock. Now I have to figure a way to send this garbage back and get my money back.

by: Jason 10/06/2025

Overall I am really satisfied with the lock, it is nice and sturdy. As a few others have reported the upper part of the collar was about 10 thousandths of an inch to small to fit over the upper part of the king pin. I got out the Dremel an sanded the inside of the collar and it fits like a charm now.

by: David 07/06/2025

Looks like a good product, but I will have to adjust since it won't completely slide on the 5th wheel pin, and latch.

Gwendolyn Y.

7/15/2025

That sounds frustrating. We haven't ran into any fitment issues so I'm curious to know what brand of king pin that's on your camper. Let me know when you have some time, David.

by: Thomas 10/07/2025

It nice to be able to lock the king pin without getting grease all over your hand.

by: Greg 01/08/2025

Very easy and secure

Greg One Year Later

1/9/2026

Awesome as it should

Gwendolyn Y.

1/9/2026

@Greg Glad to hear the Trimax lock is keeping your 5th wheel safe!

by: Robert 05/18/2025

This is great! I purchased this because it is a completely round. This way the grease from the kingpin stays inside the lock. So no mess!

by: Scott 02/16/2025

Great quality product at a reasonable price. Easy install and very effective pin hitch lock .. would buy again

by: James 02/27/2024

This isn't going to deter the thief with an acetylene torch or a master barrel key, but it will stop that boondox "theft of opportunity".
As capable as locks costing much more.
Extremely visible!

by: Robin 11/01/2024

We purchased this to replace an aging pin lock that is more difficult to attach. We like the bright color, making this much more obvious. The lock is based on a solid steel pin about 3/8" in diameter that extends over the bottom collar of the pin. As long as it is truly made of hardened steel, it should be enough of a deterrent to a would-be thief.

by: Kenneth 04/02/2023

The fit is great for protection of the 5th wheel trailer from anyone other than myself that may want to borrow the coach.

by: James 09/05/2024 One Year Later

Excellent pin lock rust proof and easy to use thx etrailer

James One Year Later

9/6/2025

It’s been a year with my king pin lock and it is still working excellent

by: Oscar 02/14/2024

I have not opened the box yet but I was thinking the kingpin lock would be heavier weight.

by: Robert 12/28/2024

Lightweight and easy to use. The bright yellow color will make it easy to find in my storage compartment.

by: TomT 07/17/2025

as usual, ease in finding, ordering and fast delevry.

by: Perry 10/03/2023 One Year Later

It does exactly what it's supposed to do. It is substantial and provides the additional security I need.

by: Jason 12/04/2022

This lock is easy to use and a great visual deterrent. I don't know if it would stand up to a determined thief with time tools and a hidden location. But, for a trailer in a somewhat secure location it seems like it will serve well.

Jason One Year Later

12/5/2023

After a year I am happy with this lock. It is easy to use and a good visual deterrent. Will it stop everyone? Nope, but it is solid and bright yellow. It says move to the next trailer.

by: Joe 04/03/2025 One Year Later

I had to glue the lock in do to it falling out.

by: Richard 02/27/2025

Good service and easy to order in order was on time. Thank you so much appreciate it.

by: Mack 01/28/2025

Fits great. Works great. Seems to be pretty tough.

by: Kearny 02/26/2025

great deal

by: jim 12/21/2024

It was exactly what I ordered it works great thanks

by: Robert 02/12/2023

Great product for a good price. Won’t stop a thief with a cutting torch, but it will send the average thief to another RV!

by: Paul 06/22/2026 One Year Later

113

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See what our Experts say about this Trimax Locks King Pin Locks

Do you have a question about this King Pin Lock?

King Pin Locks Compatible With PullRite Superglide Capture Plates
The Trimax King Pin Lock # TMX56RR can still be used with your 5th wheel having a capture plate from PullRite. The capture plate mounts to the top of the kingpin and only takes up a similar amount of space that a Lube Plate # RP83002 would. If you happen to have one of the few capture plates which also has a funnel type block welded near the king pin you would want to consider a lock like the etrailer # e98896 as it does not have the section which slides over the top of the king pin channel.
view full answer...
What is the Difference Between the Red and Yellow Trimax King Pin Locks?
Hey Tom! The Red Trimax King Pin Lock # TMX36RR and the Yellow Lock # TMX56RR are literally the same lock, just with different colors. I'm not sure why there's a price difference like that, but usually I tell people to take advantage of the lower price while you can. What drew you to this king pin lock?
view full answer...
Locks Available For A Gooseneck Trailer
Hi Alvin! There are a couple ways to lock a gooseneck trailer, but not as many as other styles. If it will fit, I am a fan of the Blaylock EZ Lock Gooseneck Coupler Lock # BLTL-50-40D. It's easy to install and is American made. The only thing is, it is designed to fit Bulldog, Stallion, Superior, and T.E.M. Gooseneck Couplers. There are instances where it fit other things as well, but if you take a look at the picture I included, you can get a good idea of if it will fit your trailer...
view full answer...
Recommended King Pin Lock For a 5TH Wheel Caming Trailer
I recommend the Trimax King Pin Lock for 5th Wheel Trailers in Red # TMX36RR or Yellow # TMX56RR. The bright colors allow you to easily see it is in place and helps to deter would be thieves. They both have a tamper resistant lock and fully incase the king pin. For extra protection the Red # TMX36RR lock uses a hardened steel that is more durable and will not cut as easy as the Yellow # TMX56RR.
view full answer...
Troubleshooting Unlocking the Trimax King Pin Lock
Sometimes keys won't fully seat into the lock core (from our experience with the various locks we carry) and so I recommend taking a rubber mallet and lightly tapping the inserted key to see if that helps seat everything properly so you can unlock your Trimax King Pin Lock # TMX56RR. You also might try some dry lock lube to help loosen up the core if it is seizing on you. When I reached out to my contact at Trimax they also asked if the keyhole is lining up to the left at 9 o'clock so...
view full answer...
Trimax King Pin Lock TMX56RR Does Not Fit - What Lock Is Recommended Instead?
Since the Trimax # TMX56RR did not fit, I recommend taking a look at the etrailer 5th Wheel King Pin Lock # e98896. I like this lock because it is designed to be universal, and will fit virtually any pin box with a standard kingpin. The collar of the lock is 1-1/2" tall, which allows for a secure fit, even on Pin boxes like the Morryde RPB72-FD where space may be limited. These locks can also be keyed alike, if you want to order multiple locks that use the same key.
view full answer...

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