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{{Short description|Hard attachment point on a road vehicle, used to tow a trailer}}
{{Redirect|Trailer hitch|the song|Trailer Hitch}}
{{Use dmy dates|date=July 2014}}
[[File:Kombi anhængertræk med stik.JPG|thumb|right|A tow ball mounted on the rear of a vehicle]]
[[File:Buksirovochnye.jpg|thumb|right|A screw-on tow hook mounted at the front of a vehicle]]


A '''tow hitch''' (or '''tow bar''' or '''trailer hitch''' in North America<ref>{{cite web|last=Campbell|first=Julia|date=9 September 2019|title=A Mover's Guide to Trailers & Tow Hitches|url=https://www.move.org/tow-hitch-guide/|access-date=19 February 2020|website=move.org}}</ref>) is a device attached to the [[chassis]] of a vehicle for [[towing]], or a towbar to an [[aircraft]] nose gear. It can take the form of a tow ball to allow swiveling and articulation of a [[Trailer (vehicle)|trailer]], or a tow pin, or a tow hook with a trailer loop, often used for large or agricultural vehicles where slack in the pivot pin allows similar movements. Another category is the towing [[pintle]] used on military vehicles worldwide.
[[Image:Kombi anhængertræk med stik.JPG|thumb|A tow ball mounted on the rear of a vehicle]]

A '''tow hitch''' (or '''tow bar''') is a device attached to the [[chassis]] of a vehicle for [[towing]] or a towbar to an [[aircraft]] nose gear, or paired main gears. It can take the form of a tow ball to allow swiveling and articulation of a [[Trailer (vehicle)|trailer]], or a tow [[pin]] and [[jaw]] with a trailer loop—often used for large or agricultural vehicles where slack in the pivot pin allows similar movements. Another category is the towing [[pintle]] used on military vehicles worldwide.
To tow safely, the correct combination of vehicle and trailer must be combined with correct loading horizontally and vertically on the tow ball. Advice should be heeded (see references) to avoid problems.


== Regional variations ==
== Regional variations ==
[[File:Class_III_tow hitch_with_7-pin_blade_connector.jpg|thumb|Under bumper class III receiver hitch with [[Trailer connectors in North America|7-pin blade trailer connector]]]]
[[Image:Receiver for hitch on 2008 Jeep GC.jpg|thumb|right|Class IV receiver for up to {{convert|10000|lb|0|adj=on}} towing capacity.]]
[[File:Receiver for hitch on 2008 Jeep GC.jpg|thumb|Class IV receiver for up to {{convert|10000|lb|t|adj=on}} towing capacity with wiring connector on the left side]]


=== North America ===
=== North America ===
Trailer hitches for conventional passenger cars, light-duty commercial vehicles, light trucks, and multipurpose passenger vehicles come in two main OEM or aftermarket types: receiver and bumper/fixed-drawbar.
[[File:Tow hitch 5.jpg|thumb|left|[[Janney coupler|AAR Type "E" coupler]] serving as a tow hitch on a [[mobile crane]]. Pulling up on the link at the rear releases the knuckle allowing uncoupling.]]

In North America the vehicle attachment is known as the ''trailer hitch''. Trailer hitches come in two main configurations: receiver type and fixed-drawbar type. Receiver-type hitches consist of a portion that mounts to the frame of the vehicle that has a rearward-facing opening that accepts removable ball mounts, hitch bike racks, cargo carriers, or other hitch mounted accessories. Fixed-drawbar hitches are typically built as one piece, have an integrated hole for the trailer ball, and are generally not compatible with aftermarket hitch accessories.
Receiver-type hitches consist of a portion with a rearward-facing opening that accepts removable aftermarket hitch-mounted accessories: trailer hitch ball mounts, hitch bike racks, cargo carriers, etc.

Bumper/fixed-drawbar type hitches typically are built as one piece, have an integrated hole (sometimes more than one hole on pickup trucks) for the trailer ball mount, and are generally not compatible with aftermarket hitch-mounted accessories.

Outside North America, the vehicle mounting for the tow ball is called the tow bracket.{{citation needed|date=October 2021}} The mounting points for all recent passenger vehicles are defined by the vehicle manufacturer and the tow-bracket manufacturer must use these mount points and prove the efficacy of their bracket for each vehicle by a full rig-based [[Fatigue testing|fatigue test]].


==== Ball mounts ====
A trailer hitch typically bolts to the chassis of the vehicle. In North America there are a few common classes: I, II, III, IV that are defined by the [[Society of Automotive Engineers|SAE]]. Some manufacturers market Class V hitches, but there is no such thing according to SAE J684.
The trailer hitch ball attaches to a ball mount; with a diameter typically {{convert|1/16|in}} larger than the ball bolt/shank diameter.<ref>{{Cite web|title=Nissan Towing Guide|url=https://www.nissanusa.com/content/dam/Nissan/us/manuals-and-guides/shared/2020/2020-nissan-towing-guide.pdf}}</ref> The ball mount must match the SAE hitch class.<ref>{{Cite web|title=J684: Trailer Couplings, Hitches, and Safety Chains--Automotive Type - SAE International|url=https://www.sae.org/standards/content/j684_200507/|access-date=2021-09-03|website=www.sae.org}}</ref> The ballmount for a receiver-type hitch is a square bar that fits into a receiver attached to the vehicle. Removable ball mounts are offered with a varying rise or drop to accommodate variations in the height of the vehicle and trailer to provide for level towing.


==== Load classes ====
A trailer hitch typically bolts to the chassis of the vehicle. In North America, there are a few common trailer hitch classes (I, II, III, and IV) that are defined by the [[Society of Automotive Engineers]] (SAE).<ref name=USDOT2000>{{cite journal |title=US Department of Transportation |journal=Federal Register |date=25 September 2000 |volume=65 |issue=186 |pages=57643–57646 |url= https://books.google.com/books?id=p8KRILhbmZkC&q=Towing+Receiver+Class&pg=PA57644 |publisher=National Archives and Records Service, General Services Administration |access-date=29 October 2020}}</ref>
: Class I – up to {{convert|2000|lb|kg}} – light loads
: Class I – up to {{convert|2000|lb|kg}} – light loads
: Class II – up to {{convert|3500|lb|kg}} – light loads
: Class II – up to {{convert|3500|lb|kg}} – light loads
: Class III – up to {{convert|5000|lb|kg}} – larger loads (campers, boats, etc.)
: Class III – up to {{convert|5000|lb|kg}} – larger loads (campers, boats, etc.)
: Class IV – up to {{convert|10000|lb|kg}} – larger loads (campers, boats, etc.)
: Class IV – up to {{convert|10000|lb|kg}} – larger loads (campers, boats, etc.)
Some manufacturers market Class V hitches, but there was no such standard listed in the 2014 version of SAE J684.<ref>{{cite web|url= http://standards.sae.org/j684_201405/ |title=Trailer Couplings, Hitches, and Safety Chains -- Automotive Type (Standard: J684, Revision: A) |date=30 May 2014 |publisher=SAE International |access-date=31 July 2014}}</ref>
: Class V – up to {{convert|17000|lb|kg}} – larger loads (construction equipment, etc.)
: "Class V" – up to {{convert|17000|lb|kg}} – larger loads (construction equipment, etc.)


==== Receiver tube sizes ====
Receiver-type hitches are typically offered with a square receiver opening of {{convert|1.25|in}} (for Class I/II) or {{convert|2|in}} (for Class III/IV/V). Some Class IV/V hitches are available in {{convert|2.5|in}} opening sizes.
A '''receiver hitch'''<!-- bolded per [[WP:MOSBOLD]] as a redirect target --> can accommodate a variety of different tow hitches when the tow hook/ball may be attached via a receiver tube attached to the tow vehicle. Trailer hitch receiver tubes may be bolted, welded, or integral to the vehicle chassis, and come in various sizes depending on the load they are designed to carry and the country of operation. The US standards are:


* Class I and II: {{convert|1+1/4|in|mm|sigfig=3|abbr=on}} light or medium duty<ref name=USDOT2000/> receiver tube
The trailer tongue (North America) or coupling (outside North America) slips over a tow ball. Tow balls come in various sizes depending on the load they carry and the country of operation:
*{{convert|1+7/8|in|mm|sigfig=3|abbr=on}}
* Class III and IV: {{convert|2|in|mm|sigfig=3|abbr=on}} heavy duty<ref name=USDOT2000/> receiver tube
*{{convert|50|mm|in|sigfig=3}} (ISO standard)
* Class V: {{convert|2|or|2+1/2|in|mm|sigfig=3|abbr=on}} receiver tube
*{{convert|2|in|mm|sigfig=3}}
*{{convert|2+5/16|in|mm|sigfig=3|abbr=on}}


==== Ball sizes ====
In North America, the ball attaches to a ballmount. Receiver-type hitches use removable ball mounts, whereas the fixed drawbar type hitches have integrated ball mounts. The ball mount must match the SAE hitch class. The ballmount for a receiver-type hitch is a rectangular bar that fits into a receiver attached to the vehicle. Removable ball mounts are offered with varying rise or drop to accommodate variations in the height of the vehicle and trailer to provide for level towing.
[[File:Ball and Socket Swiveling mainly left and right wk.png|thumb|right|upright|Operation of tow ball with trailer hitch mounted]]


Trailer hitch balls come in various sizes depending on the load they carry and the country of operation, with removable types consisting of a bolt/shank to attach to the ball mount. The trailer tongue (North America) or coupling (outside North America) slips over a trailer hitch ball attached to a receiver hitch mount or integral with the hitch.
In order to tow safely the correct combination of vehicle and trailer must be combined with correct loading horizontally and vertically on the tow ball. Advice should be taken (see references) to avoid problems.


A larger, heavy-duty gooseneck ball size: {{convert|3|in|mm|sigfig=3|abbr=on}} is typically used for towing greater than {{convert|10,000|lb|t}}, and this towing capacity falls outside of the scope of SAE J684 trailer hitch classes.
Outside North America, the vehicle mounting for the tow ball is called the tow bracket. The mounting points for all recent passenger vehicles are defined by the vehicle manufacturer and the tow-bracket manufacturer must use these mount points and prove the efficacy of their bracket for each vehicle by a full rig-based fatigue test.
{| class="wikitable"
|+ Typical North American hitch ball sizes
! scope=col | Ball size
! scope=col | Bolt/shank diameter
! scope=col | Typical max capacity
|-
| rowspan="2" |{{convert|1+7/8|in|mm|sigfig=3|abbr=on}}
|{{convert|3/4|in|mm|sigfig=3|abbr=on}}
|{{convert|2000|lbs|kg|sigfig=3|abbr=on}}
|-
|{{convert|1|in|mm|sigfig=3|abbr=on}}
|{{convert|2000|lbs|kg|sigfig=3|abbr=on}}
|-
| rowspan="4" |{{convert|2|in|mm|sigfig=3|abbr=on}}
|{{convert|3/4|in|mm|sigfig=3|abbr=on}}
|{{convert|3500|lbs|kg|sigfig=3|abbr=on}}
|-
|{{convert|1|in|mm|sigfig=3|abbr=on}}
|{{convert|6000|lbs|kg|sigfig=3|abbr=on}}
|-
|{{convert|1+1/4|in|mm|sigfig=3|abbr=on}}
|{{convert|6000|lbs|kg|sigfig=3|abbr=on}}
|-
|{{convert|1+3/8|in|mm|sigfig=3|abbr=on}}
|{{convert|10000|lbs|kg|sigfig=3|abbr=on}}
|-
| rowspan="2" |{{convert|2+5/16|in|mm|sigfig=3|abbr=on}}
|{{convert|1|in|mm|sigfig=3|abbr=on}}
|{{convert|6000|lbs|kg|sigfig=3|abbr=on}}
|-
|{{convert|1+1/4|in|mm|sigfig=3|abbr=on}}
|{{convert|10000|lbs|kg|sigfig=3|abbr=on}}
|-
|{{convert|3|in|mm|sigfig=3|abbr=on}}
|{{convert|2|in|mm|sigfig=3|abbr=on}}
|>{{convert|10000|lbs|kg|sigfig=3|abbr=on}}
|}


==== Truck variants ====
Additionally, many pickup trucks come equipped with a 1 to 3 mounting holes placed in the center area of the rear bumper to accommodate the mounting of trailer tow balls. The ones on the extreme left or right are often used by drivers in rural areas who tow wide farm equipment on 2 lane roads. The far side mounting allows for the item (trailer, etc.) being towed to be further away from the opposite side of the road (on coming traffic, etc.). Caution must be taken when using the bumper of a pickup truck for towing rather than using a frame mounted receiver hitch, as the bumper does not provide for as much strength and therefore is generally used to tow lighter types of loads. Weight ratings for both bumper mounted and frame mounted receiver hitches can be found on bumper of pickup trucks (for bumper mounted trailer tow balls) and on the receiver hitch (for frame mounted receiver hitches). Many pickup trucks without frame mounted receiver hitches often use the rear bumper, especially if the pickup truck is a light duty (not full size) pickup truck.
[[File:Horse trailer hitch (5909828571).jpg|thumb|right|upright|Heavy trailer mounted on a gooseneck hitch inside pickup truck bed]]

Weight ratings for both bumper-mounted and frame-mounted receiver hitches can be found on the bumper of pickup trucks (for bumper-mounted tow balls) and on the receiver hitch (for frame-mounted receiver hitches).

For flat deck and pickup trucks towing {{convert|10000|to|30000|lb|t|adj=on}} [[Trailer (vehicle)|trailers]] there are [[Trailer (vehicle)#Fifth wheel and gooseneck|fifth wheel and gooseneck]] hitches. These are used for agriculture, industry, and large recreational trailers.

Front trailer hitches are also used on pickup trucks, full-size SUVs, and RVs for multiple purposes.<ref>{{cite web|first=Scott C. |last=Benjamin |title=How Front-mount Receivers Work |date=8 October 2008 |work=HowStuffWorks |url= https://auto.howstuffworks.com/auto-parts/towing/equipment/hitches/front-mount-receivers.htm |access-date=6 July 2021}}</ref> A front-mounted hitch can accommodate additional truck equipment such as front mount bike carriers, fishing/hunting gear, [[winch]]es, step plates, and snowplows. It also allows a driver to maneuver a trailer with better visibility into a parking site. Front trailer hitches are mounted directly to the frame of a vehicle to ensure a reliable connection. Front hitches are typically equipped with standard-sized receiver tubes to accommodate a variety of removable aftermarket hitch mounted accessories.


===Europe===
===Europe===
[[File:Tow ball 50mm.png|thumb|Coupling ball of Class A . (Tow ball {{cvt|50|mm|in|2|disp=sqbr}}). Dimension according to regulation No 55 of the Economic Commission for Europe of the United Nations (UNECE) — Uniform provisions concerning the approval of mechanical coupling components of combinations of vehicles [2018/862], ANNEX 5, Figure 2.<ref name="Tow ball 50">{{CELEX|42018X0862|format=HTML|text=Regulation No 55 of the Economic Commission for Europe of the United Nations (UNECE) — Uniform provisions concerning the approval of mechanical coupling components of combinations of vehicles [2018/862]}}, ANNEX 5, Figure 2</ref>]]
[[File:Kovil tow hook.JPG|thumb|left|A tow hook mounted on the rear of a vehicle]]
[[File:Coupling caravan car.jpg|thumb|right|A trailer coupled (i.e., "hooked") onto a ball-type tow hitch]]
[[File:Coupling caravan car.jpg|thumb|right|Trailer coupled (i.e., "hooked") onto a ball-type tow hitch and electrical connector plugged in]]
In the [[European Union]], towbars must be a type approved to [[European Union directive]] 94/20/EC to be fitted to vehicles first registered on or after 1 August 1998.


In the [[European Union]], tow hitches must be a type approved by [[Directive (European Union)|European Union directive]] 94/20/EC requirements and fitted to vehicles first registered on or after 1 August 1998.<ref>{{CELEX|31994L0020|text=Directive 94/20/EC of the European Parliament and of the Council of 30 May 1994 relating to the mechanical coupling devices of motor vehicles and their trailers and their attachment to those vehicles}}. No longer in force. In force since 06/07/2022: {{CELEX|32019R2144|text=Regulation (EU) 2019/2144}}</ref>
The ISO standard tow ball is 50&nbsp;mm in diameter and conforms to a standard BS AU 113b (replaced by BS ISO 1103:2007). The ISO standard has been adopted in most of the world outside North America.

[[File:Pkw haenger kupplung.jpg|thumb|Tow hook mounted on the rear of a vehicle]]

Outside of North America, the ISO standard tow ball that has been adopted in most of the world is {{convert|50|mm|frac=32|abbr=on}} in diameter and conforms to a standard BS AU 113b (replaced by BS ISO<ref>{{Cite web|title=ISO - 43.040.70 - Couplings|url=https://www.iso.org/ics/43.040.70/x/|access-date=2021-09-03 |website=www.iso.org}}</ref> 1103:2007<ref>{{Cite web|title=ISO 1103:2007 |url=https://www.iso.org/cms/render/live/en/sites/isoorg/contents/data/standard/04/02/40254.html|access-date=2021-09-03 |publisher=ISO|language=en}}</ref>). With a minor modification, it was published by UNECE on 15 June 2018, as class A.<ref name="Tow ball 50" />


There are two main categories of ISO tow ball: the flange fitting and the swan-neck which has an extended neck fitting into the tow-bracket. Swan-neck tow balls are often removable to avoid the inconvenience of a tow ball protruding from the vehicle when not required. Some manufacturers are introducing retractable tow balls as an option.
There are two main categories of ISO tow ball: the flange fitting and the swan-neck which has an extended neck fitting into the tow-bracket. Swan-neck tow balls are often removable to avoid the inconvenience of a tow ball protruding from the vehicle when not required. Some manufacturers are introducing retractable tow balls as an option.


Across Europe around 25% of vehicles have tow balls fitted—but there are distinct regional variations, being more common in Benelux and Scandinavia. In Sweden, around 2.2 million cars of around 4.3 million (just over 50%) have tow balls.<ref>[http://www.sweden.gov.se/content/1/c6/08/17/41/3e7e2d99.pdf SOU 2007:33]</ref> In the United Kingdom the popularity of [[travel trailer|caravans]] is responsible for a high percentage number of [[4x4]] ([[SUV]]) type vehicles being fitted with tow hitches.
Across Europe around 25% of vehicles have tow balls fitted—but there are distinct regional variations, being more common in [[Benelux]] and [[Scandinavia]]. In Sweden, around 2.2 million cars of around 4.3 million (just over 50%) have tow balls.<ref>{{cite web|url= http://www.sweden.gov.se/content/1/c6/08/17/41/3e7e2d99.pdf |title=Släpvagnskörning med B-körkort (SOU 2007:33) |language=sv |year=2007 |access-date=31 July 2014}}</ref> In the United Kingdom the popularity of [[travel trailer|caravans]] is responsible for a large proportion of [[four-wheel drive]] ([[SUV]]) vehicles being fitted with tow hitches.

== Electrical connector ==
{{Main|Trailer connector}}{{See also|Anderson Powerpole|l1 = Anderson plug}}
The vehicle must also be electrically connected to the trailer. [[Trailer connector]] variants are standardised at the regional or national and local levels. Some variants are defined by the [[ISO standards for trailer connectors]].


== Trailer tow hitch ==
== Trailer tow hitch ==
Cars can include trailer tow hitch with a removable tow ball.
A car can be equipped with a trailer tow hitch with a removable tow ball.


=== Weight-distributing hitch ===
=== Weight-distributing hitch ===
A weight-distributing hitch is a "load leveling" hitch. It is a hitch setup mounted on the tow vehicle that uses spring bars under tension to distribute part of the trailer's hitch weight from the towing vehicle's rear axle to the towing vehicle's front axle and to the trailer's axle(s). It can help reduce trailer sway and hop. Trailer hop can jerk the tow vehicle. Trailer sway is sometimes called "fish tailing". At high speeds, trailer sway can become dangerous. Most vehicle manufacturers will only allow a maximum trailer capacity of {{convert|5000|lb|kg}} and {{convert|500|lb|kg}} of tongue weight without using a weight-distributing hitch. Tow vehicles often have square receiver sockets to accept weight distributing hitches.
A weight-distributing hitch is a "load leveling" hitch. It is a hitch setup mounted on the tow vehicle that uses spring bars and chains under tension to distribute part of the trailer's hitch weight from the towing vehicle's rear axle to the towing vehicle's front axle and to the trailer's axle(s). It can help reduce trailer sway and hop. Trailer hop can jerk the tow vehicle. Trailer sway is also called [[fishtailing]]. At high speeds, trailer sway can become dangerous. Most vehicle manufacturers will only allow a maximum trailer capacity of {{convert|5000|lb|kg}} and {{convert|500|lb|kg}} of tongue weight without using a weight-distributing hitch. Tow vehicles often have square receiver sockets to accept weight distributing hitches.{{citation needed|date=September 2021}}

{{multiple image
=== <span class="anchor" id="Pintle hook"></span> Pintle hook and lunette ring ===
| align = right
{{Multiple image
| direction = vertical
| width = 200
| align = center
| direction = horizontal
| width = 220
| image1 = NATO hitch.JPG
| image1 = NATO hitch.JPG
| alt1 = NATO tow hitch
| alt1 = NATO tow hitch
| image2 = NATO tow bar rotated 180 degrees.jpg
| image2 = NATO tow bar rotated 180 degrees.jpg
| alt2 = NATO tow bar
| alt2 = NATO tow bar
| caption2 = A pintle hook (top) and lunette ring (bottom), used in towing applications by the [[military]].
| caption2 = A pintle hook (left) and lunette ring (right), used in towing applications by the [[military]]
}}
}}


A lunette ring is a type of trailer hitch that works in combination with a [[pintle]] hook on the tow vehicle. A pintle hook and lunette ring make a more secure coupling, desirable on rough terrain, compared to ball-type [[Trailer (vehicle)|trailer]] hitches. It is commonly seen in towing applications in agriculture, industry, and the [[military]].{{citation needed|date=September 2021}}
=== Lunette ring ===
A lunette ring is a type of trailer hitch that works in combination with a [[pintle]] hook on the tow vehicle. A pintle hook and lunette ring makes a more secure coupling, desirable on rough terrain, compared to ball-type [[Trailer (vehicle)|trailer]] hitches. It is commonly seen in towing applications by the [[military]].


The clearance between the lunette and pintle allows for more relative motion between the trailer and tow vehicle than a ball coupling does. A disadvantage of that is the "slam" transmitted into the towing vehicle with each push/pull load reversal. This becomes a tradeoff between a more secure coupling, and a more comfortable towing experience.
The clearance between the lunette and pintle allows for more relative motion between the trailer and tow vehicle than a ball coupling does. A disadvantage of that is the "slam" transmitted into the towing vehicle with each push/pull load reversal. This becomes a tradeoff between a more secure coupling and a more comfortable towing experience.{{citation needed|date=September 2021}}

=== Gooseneck hitch ===
{{Main|Trailer_(vehicle)#Fifth_wheel_and_gooseneck|l1 = Fifth wheel and gooseneck}}

The [[Trailer (vehicle)#Fifth wheel and gooseneck|gooseneck hitch]] mounts in the middle of the truck bed. This hitch is designed to be paired with a gooseneck trailer, which can manage heavier loads than a hitch at the back of the tow vehicle.

An advantage of the gooseneck hitch is its tighter turning radius, which helps when towing a big flatbed or car hauler. Gooseneck hitches also enable use of the entire truck bed when not towing.

=== Offroad hitch ===
An offroad hitch is able to swivel 360 degrees in pitch and roll, as to accommodate extreme angles between the tow vehicle and trailer encountered when [[rock crawling]] or [[Mud bogging|mudding]].<ref>{{Cite AV media |url=https://www.youtube.com/watch?v=hv0DbXr-A_M |title=TOP 6 ARTICULATING OFFROAD TRAILER HITCHES {{!}} ROA Off-Road (2023) |date=2022-12-31 |last=ROA OFF-ROAD |access-date=2024-10-02 |via=YouTube}}</ref>

==History==
Before 1932, all trailers used only jaw or hook couplings with an eyelet for trailer towing. In 1932, Franz Knöbel, of [[Westfalia-Werke]] developed the trailer hitch with a ball head and socket joint. Franz Knöbel patented the ball head-socket joint trailer hitch invention on March 14, 1934. Westfalia holds a number of towing patents.<ref>{{Cite web|url=https://patents.google.com/patent/EP1002671A3/en|title=Trailer coupling}}</ref><ref>{{Cite web|url=https://www.westfalia-automotive.com/uk/|title=Westfalia-Automotive|website=www.westfalia-automotive.com}}</ref><ref name="auto">{{Cite web|url=https://westfalia-mobil.de/en/unternehmen/unternehmenshistorie.php|title=Westfalia – Company history &#124; Westfalen Mobil GmbH|website=westfalia-mobil.de}}</ref>


== See also ==
== See also ==
{{div col|2}}
{{div col|colwidth=23em}}
* [[Drawbar (haulage)]]
* [[Drawbar (haulage)]]
* [[Electronic stability control]]
* [[Electronic stability control]]
* [[Fifth wheel coupling]]
* [[Trailer (vehicle)#Fifth wheel and gooseneck|Fifth wheel and gooseneck]]
* [[Fifth-wheel coupling]]
* [[ISO standards for trailer connectors]]
* [[Ringfeder]]
* [[Ringfeder]]
* [[Semi-trailer]]
* [[Tow truck]]
* [[Tow truck]]
* [[Tractor]]
* [[Tractor]]
* [[Tractor unit]]
* [[Tractor unit]]
* [[Trailer brake controller]]
* [[Trailer (vehicle)]]
* [[Trailer (vehicle)]]
* [[Trailer brake controller]]
* [[Trailer connector]]
* [[Truck nuts]]
* [[Truck nuts]]
{{div col end}}
{{div col end}}


== References ==
== References ==
{{Reflist}}
<references/>


==External links==
==External links==
{{Commons category|Road vehicle couplers}}
* [http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31994L0020:EN:HTML Directive 94/20/EC of the European Parliament]
* {{CELEX|31994L0020|text=Directive 94/20/EC of the European Parliament and of the Council of 30 May 1994 relating to the mechanical coupling devices of motor vehicles and their trailers and their attachment to those vehicles}}. No longer in force. In force since 06/07/2022: {{CELEX|32019R2144|text=Regulation (EU) 2019/2144}}.
* [http://www.sizes.com/home/trailer_hitches.htm Trailer hitches]
* {{CELEX|32019R2144|text=Regulation (EU) 2019/2144 of the European Parliament and of the Council of 27 November 2019 on type-approval requirements for motor vehicles and their trailers, and systems, components and separate technical units intended for such vehicles, as regards their general safety and the protection of vehicle occupants and vulnerable road users, ...}}
* [http://www.towequipe.co.uk/advice-towbar-law.html Towbar Fitting Law]
* [https://www.sizes.com/home/trailer_hitches.htm |Trailer hitches]
* [http://ava4x4.com.auFitting a Tow Bar]

{{commons category|Road vehicle couplers}}


{{CarDesign nav}}
{{CarDesign nav}}
{{Authority control}}


{{DEFAULTSORT:Tow Hitch}}
{{DEFAULTSORT:Tow Hitch}}

Latest revision as of 01:37, 15 November 2024

"Trailer hitch" redirects here. For the song, see Trailer Hitch.

A tow ball mounted on the rear of a vehicle
A screw-on tow hook mounted at the front of a vehicle

A tow hitch (or tow bar or trailer hitch in North America[1]) is a device attached to the chassis of a vehicle for towing, or a towbar to an aircraft nose gear. It can take the form of a tow ball to allow swiveling and articulation of a trailer, or a tow pin, or a tow hook with a trailer loop, often used for large or agricultural vehicles where slack in the pivot pin allows similar movements. Another category is the towing pintle used on military vehicles worldwide.

To tow safely, the correct combination of vehicle and trailer must be combined with correct loading horizontally and vertically on the tow ball. Advice should be heeded (see references) to avoid problems.

Regional variations

[edit]
Under bumper class III receiver hitch with 7-pin blade trailer connector
Class IV receiver for up to 10,000-pound (4.5 t) towing capacity with wiring connector on the left side

North America

[edit]

Trailer hitches for conventional passenger cars, light-duty commercial vehicles, light trucks, and multipurpose passenger vehicles come in two main OEM or aftermarket types: receiver and bumper/fixed-drawbar.

Receiver-type hitches consist of a portion with a rearward-facing opening that accepts removable aftermarket hitch-mounted accessories: trailer hitch ball mounts, hitch bike racks, cargo carriers, etc.

Bumper/fixed-drawbar type hitches typically are built as one piece, have an integrated hole (sometimes more than one hole on pickup trucks) for the trailer ball mount, and are generally not compatible with aftermarket hitch-mounted accessories.

Outside North America, the vehicle mounting for the tow ball is called the tow bracket.[citation needed] The mounting points for all recent passenger vehicles are defined by the vehicle manufacturer and the tow-bracket manufacturer must use these mount points and prove the efficacy of their bracket for each vehicle by a full rig-based fatigue test.

Ball mounts

[edit]

The trailer hitch ball attaches to a ball mount; with a diameter typically 1⁄16 inch (1.6 mm) larger than the ball bolt/shank diameter.[2] The ball mount must match the SAE hitch class.[3] The ballmount for a receiver-type hitch is a square bar that fits into a receiver attached to the vehicle. Removable ball mounts are offered with a varying rise or drop to accommodate variations in the height of the vehicle and trailer to provide for level towing.

Load classes

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A trailer hitch typically bolts to the chassis of the vehicle. In North America, there are a few common trailer hitch classes (I, II, III, and IV) that are defined by the Society of Automotive Engineers (SAE).[4]

Class I – up to 2,000 pounds (910 kg) – light loads
Class II – up to 3,500 pounds (1,600 kg) – light loads
Class III – up to 5,000 pounds (2,300 kg) – larger loads (campers, boats, etc.)
Class IV – up to 10,000 pounds (4,500 kg) – larger loads (campers, boats, etc.)

Some manufacturers market Class V hitches, but there was no such standard listed in the 2014 version of SAE J684.[5]

"Class V" – up to 17,000 pounds (7,700 kg) – larger loads (construction equipment, etc.)

Receiver tube sizes

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A receiver hitch can accommodate a variety of different tow hitches when the tow hook/ball may be attached via a receiver tube attached to the tow vehicle. Trailer hitch receiver tubes may be bolted, welded, or integral to the vehicle chassis, and come in various sizes depending on the load they are designed to carry and the country of operation. The US standards are:

  • Class I and II: 1+1⁄4 in (31.8 mm) light or medium duty[4] receiver tube
  • Class III and IV: 2 in (50.8 mm) heavy duty[4] receiver tube
  • Class V: 2 or 2+1⁄2 in (50.8 or 63.5 mm) receiver tube

Ball sizes

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Operation of tow ball with trailer hitch mounted

Trailer hitch balls come in various sizes depending on the load they carry and the country of operation, with removable types consisting of a bolt/shank to attach to the ball mount. The trailer tongue (North America) or coupling (outside North America) slips over a trailer hitch ball attached to a receiver hitch mount or integral with the hitch.

A larger, heavy-duty gooseneck ball size: 3 in (76.2 mm) is typically used for towing greater than 10,000 pounds (4.5 t), and this towing capacity falls outside of the scope of SAE J684 trailer hitch classes.

Typical North American hitch ball sizes
Ball size Bolt/shank diameter Typical max capacity
1+7⁄8 in (47.6 mm) 3⁄4 in (19.1 mm) 2,000 lb (907 kg)
1 in (25.4 mm) 2,000 lb (907 kg)
2 in (50.8 mm) 3⁄4 in (19.1 mm) 3,500 lb (1,590 kg)
1 in (25.4 mm) 6,000 lb (2,720 kg)
1+1⁄4 in (31.8 mm) 6,000 lb (2,720 kg)
1+3⁄8 in (34.9 mm) 10,000 lb (4,540 kg)
2+5⁄16 in (58.7 mm) 1 in (25.4 mm) 6,000 lb (2,720 kg)
1+1⁄4 in (31.8 mm) 10,000 lb (4,540 kg)
3 in (76.2 mm) 2 in (50.8 mm) >10,000 lb (4,540 kg)

Truck variants

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Heavy trailer mounted on a gooseneck hitch inside pickup truck bed

Weight ratings for both bumper-mounted and frame-mounted receiver hitches can be found on the bumper of pickup trucks (for bumper-mounted tow balls) and on the receiver hitch (for frame-mounted receiver hitches).

For flat deck and pickup trucks towing 10,000-to-30,000-pound (4.5 to 13.6 t) trailers there are fifth wheel and gooseneck hitches. These are used for agriculture, industry, and large recreational trailers.

Front trailer hitches are also used on pickup trucks, full-size SUVs, and RVs for multiple purposes.[6] A front-mounted hitch can accommodate additional truck equipment such as front mount bike carriers, fishing/hunting gear, winches, step plates, and snowplows. It also allows a driver to maneuver a trailer with better visibility into a parking site. Front trailer hitches are mounted directly to the frame of a vehicle to ensure a reliable connection. Front hitches are typically equipped with standard-sized receiver tubes to accommodate a variety of removable aftermarket hitch mounted accessories.

Europe

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Coupling ball of Class A . (Tow ball 50 mm [1.97 in]). Dimension according to regulation No 55 of the Economic Commission for Europe of the United Nations (UNECE) — Uniform provisions concerning the approval of mechanical coupling components of combinations of vehicles [2018/862], ANNEX 5, Figure 2.[7]
Trailer coupled (i.e., "hooked") onto a ball-type tow hitch and electrical connector plugged in

In the European Union, tow hitches must be a type approved by European Union directive 94/20/EC requirements and fitted to vehicles first registered on or after 1 August 1998.[8]

Tow hook mounted on the rear of a vehicle

Outside of North America, the ISO standard tow ball that has been adopted in most of the world is 50 mm (1+31⁄32 in) in diameter and conforms to a standard BS AU 113b (replaced by BS ISO[9] 1103:2007[10]). With a minor modification, it was published by UNECE on 15 June 2018, as class A.[7]

There are two main categories of ISO tow ball: the flange fitting and the swan-neck which has an extended neck fitting into the tow-bracket. Swan-neck tow balls are often removable to avoid the inconvenience of a tow ball protruding from the vehicle when not required. Some manufacturers are introducing retractable tow balls as an option.

Across Europe around 25% of vehicles have tow balls fitted—but there are distinct regional variations, being more common in Benelux and Scandinavia. In Sweden, around 2.2 million cars of around 4.3 million (just over 50%) have tow balls.[11] In the United Kingdom the popularity of caravans is responsible for a large proportion of four-wheel drive (SUV) vehicles being fitted with tow hitches.

Electrical connector

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Main article: Trailer connector
See also: Anderson plug

The vehicle must also be electrically connected to the trailer. Trailer connector variants are standardised at the regional or national and local levels. Some variants are defined by the ISO standards for trailer connectors.

Trailer tow hitch

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A car can be equipped with a trailer tow hitch with a removable tow ball.

Weight-distributing hitch

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A weight-distributing hitch is a "load leveling" hitch. It is a hitch setup mounted on the tow vehicle that uses spring bars and chains under tension to distribute part of the trailer's hitch weight from the towing vehicle's rear axle to the towing vehicle's front axle and to the trailer's axle(s). It can help reduce trailer sway and hop. Trailer hop can jerk the tow vehicle. Trailer sway is also called fishtailing. At high speeds, trailer sway can become dangerous. Most vehicle manufacturers will only allow a maximum trailer capacity of 5,000 pounds (2,300 kg) and 500 pounds (230 kg) of tongue weight without using a weight-distributing hitch. Tow vehicles often have square receiver sockets to accept weight distributing hitches.[citation needed]

Pintle hook and lunette ring

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NATO tow hitch
NATO tow bar
A pintle hook (left) and lunette ring (right), used in towing applications by the military

A lunette ring is a type of trailer hitch that works in combination with a pintle hook on the tow vehicle. A pintle hook and lunette ring make a more secure coupling, desirable on rough terrain, compared to ball-type trailer hitches. It is commonly seen in towing applications in agriculture, industry, and the military.[citation needed]

The clearance between the lunette and pintle allows for more relative motion between the trailer and tow vehicle than a ball coupling does. A disadvantage of that is the "slam" transmitted into the towing vehicle with each push/pull load reversal. This becomes a tradeoff between a more secure coupling and a more comfortable towing experience.[citation needed]

Gooseneck hitch

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Main article: Fifth wheel and gooseneck

The gooseneck hitch mounts in the middle of the truck bed. This hitch is designed to be paired with a gooseneck trailer, which can manage heavier loads than a hitch at the back of the tow vehicle.

An advantage of the gooseneck hitch is its tighter turning radius, which helps when towing a big flatbed or car hauler. Gooseneck hitches also enable use of the entire truck bed when not towing.

Offroad hitch

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An offroad hitch is able to swivel 360 degrees in pitch and roll, as to accommodate extreme angles between the tow vehicle and trailer encountered when rock crawling or mudding.[12]

History

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Before 1932, all trailers used only jaw or hook couplings with an eyelet for trailer towing. In 1932, Franz Knöbel, of Westfalia-Werke developed the trailer hitch with a ball head and socket joint. Franz Knöbel patented the ball head-socket joint trailer hitch invention on March 14, 1934. Westfalia holds a number of towing patents.[13][14][15]

See also

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References

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  1. ^ Campbell, Julia (9 September 2019). "A Mover's Guide to Trailers & Tow Hitches". move.org. Retrieved 19 February 2020.
  2. ^ "Nissan Towing Guide" (PDF).
  3. ^ "J684: Trailer Couplings, Hitches, and Safety Chains--Automotive Type - SAE International". www.sae.org. Retrieved 3 September 2021.
  4. ^ a b c "US Department of Transportation". Federal Register. 65 (186). National Archives and Records Service, General Services Administration: 57643–57646. 25 September 2000. Retrieved 29 October 2020.
  5. ^ "Trailer Couplings, Hitches, and Safety Chains -- Automotive Type (Standard: J684, Revision: A)". SAE International. 30 May 2014. Retrieved 31 July 2014.
  6. ^ Benjamin, Scott C. (8 October 2008). "How Front-mount Receivers Work". HowStuffWorks. Retrieved 6 July 2021.
  7. ^ a b Regulation No 55 of the Economic Commission for Europe of the United Nations (UNECE) — Uniform provisions concerning the approval of mechanical coupling components of combinations of vehicles [2018/862], ANNEX 5, Figure 2
  8. ^ Directive 94/20/EC of the European Parliament and of the Council of 30 May 1994 relating to the mechanical coupling devices of motor vehicles and their trailers and their attachment to those vehicles. No longer in force. In force since 06/07/2022: Regulation (EU) 2019/2144
  9. ^ "ISO - 43.040.70 - Couplings". www.iso.org. Retrieved 3 September 2021.
  10. ^ "ISO 1103:2007". ISO. Retrieved 3 September 2021.
  11. ^ "Släpvagnskörning med B-körkort (SOU 2007:33)" (PDF) (in Swedish). 2007. Retrieved 31 July 2014.
  12. ^ ROA OFF-ROAD (31 December 2022). TOP 6 ARTICULATING OFFROAD TRAILER HITCHES | ROA Off-Road (2023). Retrieved 2 October 2024 – via YouTube.
  13. ^ "Trailer coupling".
  14. ^ "Westfalia-Automotive". www.westfalia-automotive.com.
  15. ^ "Westfalia – Company history | Westfalen Mobil GmbH". westfalia-mobil.de.
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