Trailer Hitch and Towing

Hitch Class:
Hitch classes are defined by SAE standard J684 Fifth Revision 2000

Vehicle Equipment Safety Commission Regulations (VESC) also has specs.
Minimum Requirements for Motor Vehicle Connecting Devices and Towing Methods VESC V-5

There are different interpretations on various web sites which do not agree.
e.g. Class IV GTW is listed as 10,000 at SAE J684, VESC V5, Reese, DiscountRamps.com, 12,000 lbs at etrailer and AutoAnything, and 14,000 at CURT

Terms:
GVWR - Gross Vehicle Weight Rating can refer to any towed device Gross Trailer Weight (GTW) and gross trailer weight rating (GTWR) refer to just trailers.
Minimum Requirements for Motor Vehicle Connecting Devices and Towing Methods.
GAW and GAWR - Gross Axel Weight (Rating)
TW - Tongue weight

Sources: CURT, Reese Classes, Reese Accessories, eTrailer, DiscountRamps, AutoAnything.com

Sample weights with trailer:
 - 17' fishing boat with motor 400 lbs.
 - 4x8 u-haul covered trailer 850 lbs
     130 cu ft @ 7 lbs/cf = 910 lbs - Total 1,760 lbs
 - 4x6 Utility trailer - GVWR 2000# (trailer 300#, load 1,700#)

Class	Designation	Max. GTW	Max. TW	Receiver Opening	Ball Shank Diameter	Ball Size	Pin Hole Size
I	light-duty	2,000	200	1¼"¹	¾"	1-7/8" or 2"	½"
II	medium-duty	3,500	350	1¼"	¾"	1-7/8" or 2"	½"
III	heavy-duty	5,000	500	2"	1" or 1¼	1-7/8" or 2" or 2-5/16"	5/8"
III	(WD) Weight Distributing³	6,000	750	2"	1" or 1¼"	1-7/8" or 2" or 2-5/16"	5/8"
IV		10,000	1,000	2"	1¼"	1-7/8" or 2" or 2-5/16"	5/8"
IV	(WD) Weight Distributing³	12,000- 14,000	1,200- 1,400	2"	1¼"	1-7/8" or 2" or 2-5/16"	5/8"
V	Not in SAE spec	12,000	1,200	2 or 2½"	1¼"	1-7/8" or 2" or 2-5/16"	5/8"
V	Extra Duty Not in SAE spec	15,000	1,500- 1,700	2 or 2½"	1¼"	1-7/8" or 2" or 2-5/16"	5/8"
V	(WD) Weight Distributing³	16,000- 17,000	1,600- 2,400	2 or 2½"	1¼	1-7/8" or 2" or 2-5/16"	5/8"
V	Commercial Duty CURT	20,000	2,700	2½"	1¼"	1-7/8" or 2" or 2-5/16"	5/8"

See: etrailer.com, Reese Classes

1. You can get after-market Class III hitches with a 2" receiver for vehicles which are designed to only tow Class I vehicles (e.g. Jeep Wrangler and Subaru Crosstrek) to rovide more stability for bike racks and cargo carriers.
Some accessories such as drawbars, bike racks and cargo carriers designed for class II hitches, won't work on a class I hitch with a 1¼ receiver. They have a longer shank that slides into the hitch opening which will hit a tab and stop it.
See Trailer Hitch Receiver Sizes | etrailer.com

3. A "weight distributing hitch" has extra spring bars to transfer some of the weight load to the front of your vehicle.

Source: OnTheBall.com Note: Check the specifications of your hitch. Some are not rated for weight distribution setups.

See:

Sway Control:
Many factors can contribute to trailer sway - the design of the trailer, the suspension, tire inflation pressures, configuration of the tow vehicle, towing speeds and hitch weight.
A sway control is particularly useful for longer trailers or for those with a large surface area. The addition of a friction or dual cam sway control dampens sway caused by traffic and crosswinds and contributes positively to tow vehicle and trailer stability.
They are frequently integrated into a Weight Distrbiution system.
See: Sway Control at drawtite-hitches.com
and Common Weight Distribution and Sway Control Questions | etrailer.com

Trailer Towing Guidelines:
Most trailer problems I have heard of are caused by the ball connection; Either the ball breaking off, comming loose or the hitch separating from the ball.
Always make sure the ball's weight rating is greater than the gross trailer weight rating. As for the hole diameter, it must be less than 1/16" greater than the ball shank diameter. When tightening, always use the lock washer and make sure a portion of the ball shank extends past the bottom the nut.

Towing capacity, Gross Towing/Trailer Weight (GTW), is a combination of the engine and transmission in your vehicle plus things like the wheelbase. A jeep Wrangler with short wheelbase has a lower GTW because of its shorter wheelbase. (See jeep page).

See Towing Tips in automotive

Ball Mount:

Hitch Height:

The drop required on your receiver hitch is C = A - B

Normally trailer coupler height is around 17 inches, from the ground to the bottom of the coupler, and most hitch manufacturers design their hitches to work with a ball mount that will end up very close to this measurement. etrailer.com
U-haul says to use 18" as B, Max ball height = 25"
A = 14¼" on my Subaru Crosstrek factory hitch.
B = 9" on my Carry-On utility trailer (5¼ drop)
B = 18" on a U-haul 4x8 trailer. (3¾ rise)
The Subaru Crosstrek factory ball mount has a 4¼ drop and 3½ rise
U-Haul uses a 1 7/8 or 2" ball.
My utility trailer uses a 1-7/8" ball

Ball Mount Capacity:
Ball mounts have two weight capacities: gross towing weight (GTW) and tongue weight (TW). The gross towing weight is the heaviest trailer and load that the ball mount can tow. The tongue weight is the maximum weight that can be allowed to push down on the ball mount. etrailer.com

Balls

Class	GTW	Shank Diam.	Torque
I	2,000	3/4"	160 ft lbs
II	3,500	1"	250 ft lbs
III	5,000	1- 1-1/4"	250 or 450 ft lbs
IV	10,000	1-1/4	450

Always use a split lock washer between the nut and the mount.
The shank should protrude 1 full thread beyond the nut.
You should use a torque wrench. The largest ones I saw at home depot were 250 ft lbs with a 1/2" drive 2 ft long.
A standard pipe wrench most of us have is only 1 ft long and you'd have trouble getting 160 ft lbs with it.
A hitch ball wrench is useful. The Reese and Curt wrenches are 15" you can longer ones for more torque.

Hitch Ball Wrench Extra Long 18-inch Handle - Amazon.com
A monkey wrench is also handy. I had trouble gripping the top with my channellocks.

The lock washer also took up too much room on the Reese 3/4" diameter 1-1/2" shank I got and the nut lacked 1/16 of going all the way on. Their next size up is a 2-3/8 in shank.
The CURT Trailer Ball #40050 has a 2-1/8" shank

Reese has two styles of 1-7/8" balls
The hex design allows for a one-wrench tightening system when used with a Reese InterLock ball mount.

The base of hex version was too wide to fit on my factory Subaru Crosstrek ball mount.

Installing the ball:
3/4 in shank - 160 ft lbs

Safety Checklist:

Maintenance Checklist (Up to date)
Hitch Ball Tight
Hitch Ball Lubricated
Hitch Secured in Receiver
Safety Chains Crossed (too act as a cradle for the tongue if the ball breaks) and Attached with enough slack
Coupler Latched onto Ball
Load Distributed Correctly and Securely
Trailer Level when Hooked Up
Trailer Lights Working Correctly
Lug Nuts Checked and Tightened
Inspect Tires for Cuts
Tire Pressure Checked
Breakaway Battery Charged
Breakaway Cable Hooked Up
Pin or Bolt Through Coupler Latch
Check coupler tightness, lights and safety chains after 50 miles
Block Tires When Loading or Unloading

Auto/Car Hitch packages SUVs and trucks might get all the attention when it comes to towing capability, but there are quite a few sedans, hatchbacks and wagons that also have the goods to haul some fairly heavy loads. While their tow ratings aren't as impressive as those of, say, a full-size SUV, these choices are certainly robust enough to haul a small boat for a weekend at the lake or a small camper for a few days of decadent glamping (as the British like to call luxurious camping).

Top 13 Best Cars for Towing for 2013 on Edmunds.com

Make Towing
Capacity
1. Porsche Panamera 4,850

2. BMW 5 Series Gran Turismo 4,630

3. Lincoln MKT 4,500

4. Toyota Venza 3,500

5. Volvo S60 3,300

5. Volvo S80 3,300

5. Volvo XC70 3,300

6. Subaru Outback 3,000

7. Volvo C30 2,000

8. Toyota Corolla 1,500

8. Honda Crosstour 1,500

8. Toyota Matrix 1,500

8. Acura ZDX 1,500

See:
High Gas Mileage Cars with towing ratings
SUVs With the Best Towing in 2017 | U.S. News & World Report
Curt Trailer Hitchs | CurtMfg.com
Trailer Hitches, Fifth Wheel, Ball Mounts, Hitch and Towing Accessories - etrailer.com
Auto Anything.com
Torklift Central | Find Your EcoHitch© - Trailer Hitch and Towing

Subaru:
GTW - Gross Trailer Weight, TW - Tongue weight

Model	Curb Weight	GTW¹	TW
Outback 3.6L	3,580 to 3,856	3,000	200¹
Outback 2.5L	3,580 to 3,856	2,700	200¹
Crosstrek	3,109 to 3,208	1,500²	200

1. Some after-market hitches specify 300 or 350# tongue weight.
2. GTW = 1,000 lbs without trailer brakes.
750 lbs when towing on a uphill grade for over 5 miles with an outside temperature of 104° or above.

Do not tow with a new car for the first 1,000 miles.

Subaru XV Crosstrek Hitches:

The OEM factory trailer hitch for Subaru Crostrek (XV) is more expensive ($500 installed) but has some advantages.
Designed by Subaru engineers NOT to alter the rear impact safety of the vehicle
1. It installs without any cutting or drilling of the factory sheet metal.
Note: Many of the aftermarket hitches attach without any drilling also.
2. The price also includes a "plug-and-play" trailer wiring harness which requires no splicing.

Subaru Crosstrek Factory hitch
14¼ to the top of the hitch .
Ball mount has a 3¾ drop and 3¼ rise
See Also:
Details about the OEM trailer hitch, European version? | SubaruXVForum.com
Others:
2013 Subaru XV Crosstrek Trailer Hitch | etrailer.com

The Torklift Central EcoHitch Invsi ($275) (1¼ or 2") goes behind the bumper plug or Knockout plate, so there is more ground clearance.
17¾ to the top of the hitch.
See Help with TorkLift or factory hitch? - Club Crosstrek | Subaru XV Crosstrek Forums
It requires more work to install, but you can do it if you are handy.
Subaru Crosstrek Ecohitch Invisi Install - YouTube

Curt T Connectors - Plug-in wiring harness

Other hitch products:

Mounts in licence plate light hole or drill a hole in the bumper.
CURT Manufacturing - CURT 4-Way Flat License Plate Light Plug Adapter #58404

Using an expander to connect a 2" attachment to a 1¼ receiver tube will rduce your tongue weight capacity by 50%.

See:
Trailers and towing article.
U-Haul: Towing glossary
Sizing Up Trailer Hitches and Couplers | West Marine

Dealers:
OnTheBall.com
HitchFinder.com (After 2 weeks they still had not shiped my Draw-Tite order)
JC Whitney
ETrailer.com
USA-Trailer-Hitches.com
Manufacturers:
Cequent Towing Products, Plymouth MI, 734 656-3000, a TriMas Corp. operating group, now owns the following Brands:
Draw-Tite®
Reese®
Hidden-Hitch®
Fulton®, Wesbar®, Bull Dog®

last updated 24 June 2017

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