Towing has its own vocabulary, and a lot of it shows up on stickers, in owner's manuals and in advice from other drivers without any explanation. This glossary covers the trailer and towing terms you're most likely to come across, plus a few that come up in The Trailer Parker. Where a topic has its own article, the entry links to it.
A · B · C · D · F · G · H · J · L · P · R · S · T · U · W
A
- Axle
- The shaft the wheels turn on. A single-axle trailer has one; a tandem-axle trailer has two, side by side.
B
- Backup camera
- A camera showing the view behind the vehicle or trailer. On a trailer, it's mounted at the rear so you can see what the trailer is backing toward. See Mirrors and Backup Cameras for Towing.
- Ball mount
- The removable bar that slides into the hitch receiver and holds the hitch ball. Also called a drawbar or shank. See How to Hitch Up a Trailer.
- Blind-side backing
- Backing a trailer around a turn toward the passenger side, where the trailer is hard to see in the mirrors. See Backing into a Campsite or Driveway.
- Brake controller
- A device in the tow vehicle that operates a trailer's electric brakes and lets you adjust how strongly they apply. See Trailer Weight and Tongue Weight.
- Breakaway cable
- A cable from the trailer to the tow vehicle that applies the trailer's brakes if the trailer completely separates. See How to Hitch Up a Trailer.
- Bumper pull
- A conventional trailer that attaches to a hitch at the back of the tow vehicle, as opposed to a fifth wheel or gooseneck.
- Bunks
- The padded boards a boat rests on when it sits on a boat trailer. Some trailers use rollers instead. See Backing a Boat Trailer Down a Ramp.
C
- Coupler
- The socket at the front of the trailer tongue that fits over the hitch ball and latches onto it. See How to Hitch Up a Trailer.
D
- Direction change
- Switching between forward and reverse. Fewer direction changes during a park usually means a cleaner back-up.
- Driver-side backing
- Backing around a turn toward the driver's side, where you can see the trailer through your window and left mirror. Easier than blind-side backing. See Backing into a Campsite or Driveway.
- Dry weight
- A trailer's weight as built, without water, propane, cargo or gear. The loaded weight is always higher. See Trailer Weight and Tongue Weight.
F
- Fifth wheel
- A trailer that hitches to a large coupling plate mounted in the bed of a pickup, over or slightly ahead of the rear axle. See Short vs Long Trailers.
G
- GAWR
- Gross Axle Weight Rating: the maximum weight a single axle is rated to carry. See Trailer Weight and Tongue Weight.
- GCWR
- Gross Combined Weight Rating: the maximum allowed weight of the loaded tow vehicle and loaded trailer together. See Trailer Weight and Tongue Weight.
- GOAL
- Get Out And Look. Stopping to check your surroundings in person when you're not sure what's behind or beside the trailer. See How to Back Up a Trailer.
- Gooseneck
- A trailer that hitches to a ball mounted in the bed of a pickup, similar in position to a fifth wheel. See Short vs Long Trailers.
- GVWR
- Gross Vehicle Weight Rating: the maximum a vehicle, or a trailer, may weigh when fully loaded. See Trailer Weight and Tongue Weight.
H
- Hand-at-the-bottom trick
- Placing a hand at the bottom of the steering wheel when backing, then moving it in the direction you want the trailer to go. See How to Back Up a Trailer.
- Hitch
- The equipment that connects a trailer to a tow vehicle. Often used to mean the receiver, ball mount and ball together. See How to Hitch Up a Trailer.
- Hitch angle
- The angle between the tow vehicle and the trailer, measured at the hitch. Zero when the rig is straight. See How to Avoid Jackknifing a Trailer.
- Hitch ball
- The metal ball on the ball mount that the trailer coupler sits on. Common sizes are 1-7/8, 2 and 2-5/16 inches. See How to Hitch Up a Trailer.
J
- Jackknife
- When the tow vehicle and trailer fold toward each other at a sharp angle, so the trailer can no longer be steered back while reversing. See How to Avoid Jackknifing a Trailer.
L
- Launch
- Putting a boat into the water from its trailer at a boat ramp. See Backing a Boat Trailer Down a Ramp.
- Loaded weight
- The actual weight of a trailer with everything in or on it. The number that matters for every rating. See Trailer Weight and Tongue Weight.
P
- Payload
- How much weight a vehicle can carry, including passengers, cargo and the trailer's tongue weight. See Trailer Weight and Tongue Weight.
- Point of no return
- The hitch angle beyond which the trailer can't be straightened while continuing to back up. The only fix is to pull forward. See How to Avoid Jackknifing a Trailer.
- Power loading
- Driving a boat onto its trailer under engine power. Banned at many ramps because the prop wash erodes the ramp. See Backing a Boat Trailer Down a Ramp.
- Pull-up
- Stopping and driving forward to straighten the rig before backing again. Also called a reset. See How to Back Up a Trailer.
R
- Receiver
- The square tube under the back of the tow vehicle that the ball mount slides into. See How to Hitch Up a Trailer.
- Retrieve
- Loading a boat back onto its trailer and pulling it out of the water. See Backing a Boat Trailer Down a Ramp.
- Rig
- The tow vehicle and trailer together.
S
- Safety chains
- Two chains from the trailer tongue to the tow vehicle, crossed under the tongue, that hold the trailer if the coupler comes off. See How to Hitch Up a Trailer.
- Setup
- Positioning the rig before backing so the trailer is already lined up with, or angled toward, the space. See How to Back Up a Trailer.
- Spotter
- A helper outside the vehicle who guides the driver, standing where the driver can always see them in a mirror. See Backing into a Campsite or Driveway.
- Staging area
- A space near a boat ramp for getting the boat ready before launching and securing it after retrieving. See Backing a Boat Trailer Down a Ramp.
- Sway
- A side-to-side wagging motion of a trailer behind the tow vehicle, often caused by too little tongue weight, crosswinds or high speed. See Trailer Weight and Tongue Weight.
- Sway control
- A device or electronic system that resists trailer sway. Many tow vehicles have it built in. See Trailer Weight and Tongue Weight.
T
- Tandem axle
- Two axles mounted close together on a trailer. The pivot point when backing is roughly midway between them. See Short vs Long Trailers.
- Tongue
- The front part of the trailer frame that extends forward to the coupler.
- Tongue jack
- A crank or jack at the front of the trailer used to raise and lower the tongue when hitching and unhitching. See How to Hitch Up a Trailer.
- Tongue weight
- The downward force the trailer tongue puts on the hitch ball, commonly about 10 to 15 percent of a bumper-pull trailer's loaded weight. See Trailer Weight and Tongue Weight.
- Tow vehicle
- The truck, SUV or car pulling the trailer.
- Towing capacity
- The maximum trailer weight a vehicle's manufacturer says it can tow when properly equipped. See Trailer Weight and Tongue Weight.
- Towing mirrors
- Mirrors that extend further from the vehicle than standard ones, so you can see past the sides of a wide trailer. See Mirrors and Backup Cameras for Towing.
- Transom straps
- Straps that hold the back of a boat down to its trailer while towing. Removed before launching. See Backing a Boat Trailer Down a Ramp.
U
- Utility trailer
- A small, open trailer for hauling things like yard waste, furniture or equipment. Often short, which makes it twitchy in reverse. See Short vs Long Trailers.
W
- Weight-distribution hitch
- A hitch system using spring bars to spread tongue weight across the tow vehicle's axles and the trailer. See Trailer Weight and Tongue Weight.
- Wheel chock
- A wedge placed against a tire to stop a vehicle or trailer from rolling. See How to Hitch Up a Trailer.
- Winch strap
- The strap on a boat trailer's winch that pulls the boat up and holds its bow against the bow stop. See Backing a Boat Trailer Down a Ramp.
- Wiring connector
- The plug that connects the trailer's lights, and its electric brakes if fitted, to the tow vehicle. See How to Hitch Up a Trailer.