Hitches, Receivers & Ball Mounts
The Best Hitch Locks and Anti-Rattle Devices
Two problems, two inexpensive parts. Between them they cure the most annoying and the most avoidable issues with a receiver.
Disclosure: we earn a commission if you buy through the Amazon links on this page, at no extra cost to you. Commission never decides a verdict or a ranking position - read our editorial policy and affiliate disclosure.
How we assessed these: Selected from published specifications and the failure modes each design is exposed to. No lock is unbeatable and we make no security claims beyond what the makers publish.
Short answer
An anti-rattle pin with a wedge shim removes the clunk from the receiver. A keyed receiver lock stops someone walking off with your mount. A coupler lock is the one that matters for an unattended trailer - it stops another vehicle simply hitching up and driving away.
Why the receiver rattles
A 2 in mount in a 2 in receiver needs clearance to slide in at all. That clearance lets the mount move a fraction of an inch under load reversal - which is exactly what happens at every expansion joint, every gear change and every stop. The resulting clunk sounds structural and is not.
A wedge shim takes up the gap, converting a sliding fit into an interference fit. CURT's version is a pin plus shim for 2 in receivers with a 1/2 in pin hole, in yellow zinc. Before you buy one, confirm the noise is coming from the receiver and not from a loose ball nut or a worn coupler, because a shim will mask neither.
What each lock actually prevents
| Lock | Prevents | Does not prevent |
|---|---|---|
| Receiver / hitch pin lock | Someone removing the ball mount from the receiver | Theft of the trailer itself |
| Coupler lock | Another vehicle hitching to your parked trailer | Anything once the trailer is hitched to you |
| Wheel lock or chock | The trailer being towed away at all | Theft of contents |
Quick picks
Tap any row to jump to the full write-up. How these are chosen - and what we do and do not claim to know - is published in full on our research methodology page.
| # | Product | Best for | Our read | Price |
|---|---|---|---|---|
| 1 |  CURT Anti-Rattle Hitch Pin and Shim (2 in receiver) Best anti-rattle | Killing receiver rattle | Pin and wedge shim, 2 in receivers | Check price on Amazon #ad Affiliate link - we publish no price; Amazon shows the current one |
| 2 |  Trimax Keyed Receiver Hitch Lock Best receiver lock | Leaving a mount in the receiver | Replaces the clip pin, keyed | Check price on Amazon #ad Affiliate link - we publish no price; Amazon shows the current one |
| 3 |  Master Lock Trailer Coupler Lock Best for parked trailers | Trailers parked unhitched | Blocks the actual theft method | Check price on Amazon #ad Affiliate link - we publish no price; Amazon shows the current one |
1. Best anti-rattle
CURT Anti-Rattle Hitch Pin and Shim (2 in receiver)
CURT · Best for killing receiver rattle
A pin plus a wedge shim that takes the slop out of the gap between a 2 in mount and a 2 in receiver. That gap is a manufacturing tolerance, not a fault, and this is the cheapest thing on the whole site that fixes a real, daily annoyance.
Published specifications
What works
- Removes the clunk over expansion joints for very little money
- Fits in a glovebox and transfers between vehicles
- No modification to the receiver or the mount
What does not
- Does nothing about rattle originating at the coupler or the sway bar
- Listed as superseded, so check the current item number
Skip it if
Not the fix if the noise is coming from a loose ball nut or a worn coupler - find the source first, because a shim will just mask it.
#ad Affiliate link - we publish no price; Amazon shows the current one
Raw specifications: CURT’s own page. We earn nothing on that link.
2. Best receiver lock
Trimax Keyed Receiver Hitch Lock
Trimax · Best for leaving a mount in the receiver
A locking pin that replaces the clip pin so the mount cannot be pulled out of the receiver in a parking lot. The weak point of every hitch lock is the same - weather in the lock barrel - so the only maintenance that matters is a cover and the occasional shot of lubricant.
We have not sourced a full specification table for this model from the manufacturer’s own site at a stable address. Rather than repeat figures we cannot cite, the assessment above is limited to what the design and the maker’s published description genuinely establish.
What works
- Stops the most casual theft there is - walking off with a ball mount
- Direct replacement for a standard clip pin
- Keyed, so the same key can cover more than one lock
What does not
- Lock barrels seize when they live in road salt without a cover
- Determined thieves defeat any hitch pin lock given time
Skip it if
Pointless if you take the mount out each time anyway - that is already a better anti-theft measure than any lock.
#ad Affiliate link - we publish no price; Amazon shows the current one
3. Best for parked trailers
Master Lock Trailer Coupler Lock
Master Lock · Best for trailers parked unhitched
Fills the coupler so another vehicle cannot drop a ball into it while the trailer is parked. It is the lock that matters for an unattended trailer, and it is the one most people skip in favor of a wheel lock that takes longer to fit.
We have not sourced a full specification table for this model from the manufacturer’s own site at a stable address. Rather than repeat figures we cannot cite, the assessment above is limited to what the design and the maker’s published description genuinely establish.
What works
- Blocks the actual theft method - backing up to an unattended coupler
- Fits in seconds, unlike a wheel clamp
- Weather-resistant body suited to being left outside
What does not
- Universal designs fit some coupler shapes better than others
- Does nothing once the trailer is hitched to your vehicle
Skip it if
Not sufficient on its own for long-term storage, where a wheel lock or a chock is the stronger deterrent.
#ad Affiliate link - we publish no price; Amazon shows the current one
Key takeaways
- Receiver rattle is tolerance, not failure - a shim removes it for a few dollars.
- Confirm the noise source before buying: a loose ball nut sounds similar.
- Coupler locks protect parked trailers; receiver locks protect mounts.
- Lock barrels seize in road salt - a cover and occasional lubricant is the whole maintenance plan.
How we sourced this
Every figure on this page came from one of the following, each fetched while the page was written. Where a manufacturer or regulator does not publish a number, we say so rather than estimate it.
Common questions
- Will an anti-rattle device stop all noise?
- It stops noise originating from play between the mount and the receiver. Noise from a worn coupler, a loose ball nut or a weight distribution hitch's friction surfaces is unaffected.
- Are hitch locks worth it?
- For a mount you leave in the receiver, yes - it is the most casual theft there is. For a trailer, a coupler lock matters more.
- My lock seized over winter. What now?
- Penetrating lubricant and patience, then a cover for next season. Lock barrels exposed to road salt without a cover are the normal failure, not a defect.
More in Hitches, Receivers & Ball Mounts
Class, receiver size, ball diameter, drop. Four numbers decide whether your setup is right, and three of them are stamped on parts you already own.
Read next
Guide
Hitch Pin Sizes
Pin diameters and lengths, the difference between clip and locking pins, and how anti-rattle pins work.
Best hitch hardware
Best Trailer Hitches
What to buy for a 2 in receiver - mounts, balls, pins and anti-rattle hardware - and how to get the vehicle-specific receiver right.
Best ball mount
Best Ball Mounts
Fixed, adjustable, stowing and scale-equipped mounts compared on drop range, capacity and how much they rattle.
Reference
Trailer Ball Sizes
The three standard ball diameters, how shank dimensions work, and why mounting torque is a specification rather than a suggestion.
Found something out of date, or a figure you can source better than we did? Corrections get read first. How we research explains how these pages are put together, and contact is one click away.