Hitches, Receivers & Ball Mounts
Hitch Pin Sizes and Locks
A two-dollar part that holds everything together, in two sizes people routinely mix up.
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Short answer
Two pin diameters cover almost everything: 1/2 in for 1-1/4 in receivers and 5/8 in for 2 in receivers - though some 2 in receivers use 1/2 in. Measure the hole rather than assuming, especially before ordering an anti-rattle pin.
Diameter, length and why both matter
Diameter has to match the hole closely - a loose pin lets the mount move, which is rattle at best. Usable length has to clear the receiver's full width plus the mount, with enough left over for the clip or the lock mechanism. A pin that is too short will not retain its clip properly, which is the failure that matters.
| Receiver | Common pin diameter | Notes |
|---|---|---|
| 1-1/4 in | 1/2 in | Class 1 and 2 accessories |
| 2 in | 5/8 in | The common case |
| 2 in (some) | 1/2 in | Check before buying anti-rattle hardware |
| 2-1/2 in and 3 in | 5/8 in | Longer usable length needed |
Three kinds of pin
- Clip pin. A plain pin with a spring clip. Cheapest, and the clip is what gets lost.
- Locking pin. A keyed barrel replaces the clip so the mount cannot be removed. Worth it if you leave the mount in the receiver.
- Anti-rattle pin. A pin with a wedge shim that takes up the play between mount and receiver. CURT's version is sold for a 2 in receiver with a 1/2 in hole in yellow zinc, and it is the cheapest genuinely useful upgrade in this category.
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 upgrade | Killing receiver rattle | Pin and shim for 2 in, 1/2 in hole | Check price on Amazon #ad Affiliate link - we publish no price; Amazon shows the current one |
| 2 |  Trimax Keyed Receiver Hitch Lock Best locking pin | Leaving a mount in the receiver | Keyed, replaces the clip pin | Check price on Amazon #ad Affiliate link - we publish no price; Amazon shows the current one |
| 3 |  CURT Loaded Ball Mount with 2 in Ball (2 in drop, 7,500 lb) What it holds in | One trailer at a known height | The mount the pin secures | Check price on Amazon #ad Affiliate link - we publish no price; Amazon shows the current one |
1. Best upgrade
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 locking pin
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. What it holds in
CURT Loaded Ball Mount with 2 in Ball (2 in drop, 7,500 lb)
CURT · Best for one trailer at a known height
A one-piece mount with the ball already fitted and torqued, rated to 7,500 lb gross and 750 lb tongue with a 2 in drop. Nothing adjusts, which is exactly why nothing rattles or works loose.
Published specifications
What works
- Arrives with the ball fitted, so there is no torque step to get wrong
- One piece means nothing to loosen or rattle
- Light enough to leave in the receiver or throw in a toolbox
What does not
- The 2 in drop is the only drop - measure before you buy
- 7,500 lb ceiling rules out heavier trailers
Skip it if
Useless on a lifted truck, where a 2 in drop will still leave the trailer nose-high and the weight on the rear axle of the trailer.
#ad Affiliate link - we publish no price; Amazon shows the current one
Raw specifications: CURT’s own page. We earn nothing on that link.
Key takeaways
- Measure the hole; 2 in receivers are not all 5/8 in.
- Usable length must clear the full receiver width plus the mount.
- An anti-rattle pin and shim is the cheapest real improvement available.
- A missing clip is a replace-now item, not a tomorrow item.
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
- Does a locking pin stop rattle?
- Not by itself - a locking pin is the same diameter as a clip pin. Anti-rattle devices use a wedge or shim to take up play, which is a different function. Some products combine both.
- What length pin do I need?
- Enough usable length to pass through the full receiver width plus the mount, with room for the clip or lock. Receiver widths differ, so measure.
- Can I use a bolt instead of a pin?
- We would not. Hitch pins are specified for shear loading and a hardware-store bolt of unknown grade is not. The part costs very little.
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
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Hitch Locks & Anti-Rattle
Anti-rattle pins, receiver locks and coupler locks - what each one actually prevents and where each one fails.
Reference
Receiver Sizes Chart
Tube sizes, pin hole diameters, what fits what, and the derating that comes with a reducer sleeve.
Best ball mount
Best Ball Mounts
Fixed, adjustable, stowing and scale-equipped mounts compared on drop range, capacity and how much they rattle.
Head to head
Hitch vs Receiver
A plain-language glossary of the hitch assembly, so that part diagrams and forum advice stop contradicting each other.
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.