CURT Hitch Pin Sizes & Receiver Guide

A receiver hitch pin needs to match more than the receiver's outside size. Check the pin-hole diameter, the width of the shank and receiver, and whether you want a clip, grooved retainer or keyed lock. CURT's half-inch and five-eighth-inch pins serve different receiver applications, and a hitch pin cannot increase the towing rating of the rest of the setup.

Three common receiver-pin designs

Standard pin and clip A bent steel pin uses a separate retainer clip. Match the pin diameter and usable reach.

Adapter sleeve pin CURT 21502 uses a half-inch pin and a removable sleeve for compatible larger pin holes.

Keyed receiver lock CURT 23021 uses a keyed deadbolt head rather than a loose clip. Confirm lock reach and accessory fit.

Conceptual pin designs, not scaled drawings or measurement templates.

Match the hole before the receiver class. Smaller 1¼-inch receivers commonly use ½-inch pins; compatible larger receivers often use ⅝-inch pins. Some receiver extensions and specialty accessories require a different usable pin length, so do not choose by diameter alone.

CURT receiver hitch pin comparison chart

CURT MPN	Diameter	Receiver application	Retention style
21401	½ in	1¼ in	Bent pin with retaining clip
21502	½ in; ⅝-in sleeve	1¼- or 2-in matched pin hole	Removable adapter sleeve
21505	⅝ in	2 in	Grooved clip end
21506	⅝ in	2½ or 3 in	Extended grooved pin; clip
21580	⅝ in	2 or 2½ in	Standard clip retention
21581	⅝ in	2 or 2½ in	Packaged pin and clip
21583	⅝ in	2 or 2½ in	Grooved clip end
23021	⅝ in	2, 2½ or 3 in	Keyed locking head and protective cap

Listed receiver sizes are model-specific applications, not proof that the pin reaches through every hitch and accessory combination.

Five checks before ordering a hitch pin or lock

Identify the receiver's inside opening size: 1¼, 2, 2½ or 3 inches, and check the actual pin-hole diameter.
Confirm the usable span of the pin across the receiver and installed shank; a thicker receiver can need a longer pin.
Choose clip-retained, grooved or locking styles according to the exact intended use. Use the proper included clip or locking head.
For CURT 21502, verify whether the removable adapter sleeve is required; never install a loose undersized pin without the correct sleeve.
Check that the hitch, shank and all towing hardware remain properly rated. A 21,000-lb rating on CURT 21506 does not increase the tow vehicle or hitch rating.

Safety and retention. A receiver pin must pass through the intended shank and receiver holes and be fully retained by its clip or lock. Follow the hitch and accessory manufacturer's instructions; never assume an incorrect diameter or missing clip is acceptable.

Compare exact CURT hitch pins and locks

Each link opens the exact NewRVParts product listing; confirm receiver and pin compatibility before ordering.

½-inch and sleeved adapter pins

CURT 21401 is a simple half-inch receiver pin; 21502 adds a removable sleeve for the specified pin-hole arrangement.

CURT 21401 ½-inch pin for small receivers catalog product photograph

CURT 21401 — ½-inch pin for small receiversZinc-plated bent hitch pin for a compatible 1¼-inch receiver's half-inch pin hole. Supplied with a clip, not a locking head.View part and availability

CURT 21502 ½-inch pin with adapter sleeve catalog product photograph

CURT 21502 — ½-inch pin with adapter sleeveA half-inch hitch pin supplied with a sleeve to adapt to selected ⅝-inch pin holes. Match the receiver, shank and the required sleeve arrangement.View part and availability

⅝-inch steel hitch pins

Standard bent and grooved designs differ in receiver application and retaining clip access. Compare the actual reach as well as the diameter.

CURT 21505 Grooved ⅝-inch receiver pin catalog product photograph

CURT 21505 — Grooved ⅝-inch receiver pinZinc-plated steel ⅝-inch grooved pin with retaining clip. The clip can be inserted from different angles around the groove.View part and availability

CURT 21506 Heavy-duty extended receiver pin catalog product photograph

CURT 21506 — Heavy-duty extended receiver pinAn extended ⅝-inch hitch pin for compatible 2½- or 3-inch heavy-duty receivers. CURT lists a 21,000-lb GTW pin rating; the lowest-rated towing component still governs.View part and availability

CURT 21580 Bent standard receiver pin catalog product photograph

CURT 21580 — Bent standard receiver pinBent zinc-plated pin supplied with a retaining clip for suitable two- or two-and-a-half-inch receiver hardware.View part and availability

CURT 21581 Packaged standard receiver pin catalog product photograph

CURT 21581 — Packaged standard receiver pinPackaged ⅝-inch bent pin and clip for compatible 2- or 2½-inch receivers. Compare exact CURT MPN to the loose-pin version.View part and availability

CURT 21583 Grooved extended receiver pin catalog product photograph

CURT 21583 — Grooved extended receiver pinGrooved ⅝-inch pin with angled clip access for 2- or 2½-inch receiver installations.View part and availability

Keyed deadbolt hitch lock

The CURT 23021 deadbolt lock has a bent ⅝-inch pin with a keyed locking head and dust cap rather than a loose retainer clip.

CURT 23021 Deadbolt keyed receiver lock catalog product photograph

CURT 23021 — Deadbolt keyed receiver lockA chrome-finished keyed receiver lock with bent ⅝-inch pin and weather-protective cap. Check its usable pin span and the combined receiver/accessory width.View part and availability

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CURT Receiver Hitch Pins: Diameter, Clips & Lock Selection