Curt
Towing 101
Accessories

Understanding Towing

It is very important to review an operator's manual before purchasing a towing system. Your vehicle manual has helpful information about your vehicle's capabilities and limitations. You also need to be aware of the different laws and restrictions which exist when you tow from state to state. The State Patrol is a good resource for information.

Gross Trailer Weight

(GTW) The gross trailer weight is the weight of the trailer & cargo. Measure this by putting the fully loaded trailer on a vehicle scale.

Gross Trailer Weight

Weight Distribution

(WD) Used to balance the weight of the cargo between the front and rear wheels throughout the trailer, allowing for better steering, braking, and level riding. Not to be used on class I or II receivers, or with surge brakes.

Weight Distribution

Sway Control

A device used to reduce the lateral movements of the trailer that are caused by the wind. This may be used in conjuction with a weight distribution hitch or alone. Do not use this on a class I or II hitch, or with surge brakes.

Sway Control

Trailer Balls

Connection from the hitch to the trailer.

There are many factors that determine the correct hitch ball:

  • Most important is the hitch ball's gross trailer weight rating.
  • The mounting platform must be at least 3/8" thick.
  • The hole diameter must not be more than 1/16" larger than the threaded shank.
  • Every time you tow, check the nut and lock washer to make sure they are fastened securely.
Trailer Balls

Ball Mounts

The ball mount is placed inside the opening of the receiver hitch which is mounted to the vehicle. Make sure a hitch pin and clip is properly securing the ball mount to the receiver hitch before you begin towing.

Ball Mounts

Bumper Hitches

These hitch applications are used only for light weight towing, including bike racks and cargo carriers. Towing should not exceed vehicle bumper's gross towing weight. Hitch capacities are limited to bumper capacities.

Bumper Hitches

Weight Carrying

(WC) The total weight of both the trailer and the cargo inside. Never exceed the weight capacity of your trailer hitch. This applies to loads without a weight distribution hitch installed.

Weight Carrying

Tongue Weight

(TW) The downward force that is exerted on the hitch ball by the coupler. The tongue weight will vary depending on where the load is positioned in relationship to the trailer axle(s). To measure the tongue weight, use either a commercial scale or a bathroom scale with the coupler at towing height. When using a bathroom scale, use the method shown and mulitply the scale reading by three.

Tongue Weight

Safety Chains

Safety chains are required by law and should be crossed under the tongue of trailer so that the tongue will not drop to the road if it becomes separated from the hitch. Always leave enough slack so you can turn. Never allow the safety chains to drag on the ground and never attach the chains to the bumper.

Trailer classification: safety chain breaking force - minuimum

Class I: 2,000 lbs. (8.9 kN)
Class II: 3,500 lbs. (15.6 kN)
Class III: 5,000 lbs. (22.2 kN)

Each safety chain or safety cable must equal or exceed the GTWR of the trailer.

Safety Chains

Couplers

The component that is placed over the trailer ball to connect the vehicle to the trailer. Coupler size must match the size of the hitch ball. Ensure the coupler handle is securely fastened. Trailer coupler size determines trailer ball size. Be sure your coupler os properly adjusted to the ball you are using.

Couplers

Hitch Pins/Locks

For securing all ball mounts to receiver style hitches. Hitch locks protect against ball mount theft.

Hitch Pinslocks

Use this table to select the correct class of hitch for your vehicle. Refer to not only vehicle type, but also the trailer(s) that you will be towing

Trailer Types Trailer Types Image Trailer Types Image Trailer Types Image Trailer Types Image
Weight Ratings
Class I

2,000 Ibs. GTW
200 Ibs. TW
Class II

3,000 Ibs. GTW
350 Ibs. TW
Class III

3,500-6,000 Ibs. GTW
350-600 Ibs. TW
Class IV-V

6,000-18,000 Ibs. GTW
600-1,800 Ibs. TW

Subcompact/
Compact Cars
Class I

Receiver

Mid-size Cars/
Small Pickups
Class I

Receiver
Class II

Receiver
Class III

Receiver with Weight
Distribution Htch

Minivans/ SUVs
Class I

Receiver
Class II

Receiver
Class III

Receiver with Weight
Distribution Htch

Full-size Cars/
Pickups/Vans/
Utility Vehicles
Class I

Receiver
Class II

Receiver
Class III

Receiver with Weight
Distribution Htch
Class III

Receiver with Weight
Distribution Htch

Class IV-V

Receiver

How Much Can You Safely Tow?

CURT Manufacturing recommends the use of hitches showing a weight distributing (WD) rating when carrying a personal mobility vehicle (power wheel chair, scooter, etc.). Use of a lower capacity hitch may void warranty and could result in damage to both the carried and carrying vehicles.

Gross Trailer Weight
1,000 Ibs.
2,000 Ibs.
3,000 Ibs.
4,000 Ibs.
5,000 Ibs.
6,000 Ibs.
7,000 Ibs.
8,000 Ibs.
10,000 Ibs.
18,000 Ibs.
Tongue Weight
100 Ibs.
200 Ibs.
300 Ibs.
400 Ibs.
500 Ibs.
600 Ibs.
700 Ibs.
800 Ibs.
1,000 Ibs.
1,800 Ibs.
Classes
Class I
Class II
Class III
Class IV
Class V

Camper
11'
12'
13'
14'
15'
16'
1,100 Ibs.
1,200 Ibs.
1,300 Ibs.
1,400 Ibs.
1,500 Ibs.
1,600 Ibs.

Vacation
14'
16'
18'
14'
20'
22'
24'
26'
28'
30'
2,100 Ibs.
2,400 Ibs.
2,700 Ibs.
3,000 Ibs.
3,300 Ibs.
3,600 Ibs.
3,900 Ibs.
4,200 Ibs.
4,500 Ibs.
4,800 Ibs.

Vacation
14'
16'
18'
14'
20'
22'
24'
26'
28'
30'
2,800 Ibs.
3,200 Ibs.
3,600 Ibs.
4,000 Ibs.
4,400 Ibs.
4,800 Ibs.
4,800 Ibs.
5,200 Ibs.
5,200 Ibs.
6,000 Ibs.

5th Whell
Refer to owner's manual for towing capabilities and limitations

Estimated Trailer Only Weights?


Boat
Aluminum

12-15 feet - Trailer weight = 200 ibs.
16-20 feet - Trailer weight = 300 ibs.

Boat
Fiberglass

Up to 17 feet - Trailer weight = 200 ibs.
18-20 feet - Trailer weight = 300 ibs.
21-22 feet - Trailer weight = 570 ibs.
22-24 feet - Trailer weight = 670 ibs.

Recreational Vehicle
Motorcycle, Snowmobile, ATV, Personal Watercraft

Carries two vehicle - trailer Weight = 250

Recreational Vehicle
Motorcycle, Snowmobile, ATV, Personal Watercraft

Carries four vehicle - trailer Weight = 250

Open
Cargo

4 feet dy 6 feet - Trailer Weight = 450 Ibs.
5 feet dy 6 feet - Trailer Weight = 450 Ibs.

Horse
One Horse Vehicle
Trailer Weight = 1,000 Ibs.
Two Horse Vehicle
Trailer Weight = 1,800 Ibs.

Other
Car Transport
Trailer Weight = 1,800 Ibs.
Garden or Equipment
Trailer Weight = 1,800 Ibs.
Tow Dolly
Trailer Weight = 500 Ibs.
Receiver Hitches

The primary device attached to the vehicle, which allows you to tow. It is very important to choose the correct class of receiver hitch. Gross trailer weight and tongue weight will determine the hitch that is needed. Do not exceed the lowest rating of any component of your towing system.

Class 1

Class 1

Ball Mount? Pin & Clip Included
Up to 2?00 Ibs. GTW
Up to 200 Ibs.TW
1 1/4'' Receiver Tube
Class 2

Class 2

Ball Mount? Pin & Clip Included
2,500 - 3,500 Ibs.GTW
250- 350 Ibs.TW
1 1/4'' Receiver Tube
Class 3

Class 3

(Round Tube)
3,500 - 8,000 Ibs. GTW
350 - 800 Ibs. TW
Up to 12,000 Ibs. WD
Up to 1,200 Ibs. WDTW
2' Receiver Tube
Heavy Duty

Heavy Duty HD

10,000 - 12,000 Ibs. GTW
1,000 - 1,200 Ibs. TW
12,000 - 14,000 Ibs. WD
1,200 - 1,400 Ibs. WDTW
2'' Receiver Tube
Xtra Duty

Xtra Duty XD

Up to 15,000 Ibs. GTW
Up to 1,500 Ibs. TW
Up to 16,000 Ibs. WD
Up to 1,600 Ibs. WDTW
2'' Receiver Tube
Commercial Duty

Commercial Duty CD

Up to 18,000 Ibs. GTW
Up to 1,800 Ibs. TW
Up to 18, 000 Ibs. WD
Up to 1,800 Ibs. WDTW
2 1/2'' Receiver Tube
Front Mount

Front Mount

Up to 5,000 Ibs. GTW
Up to 500 Ibs. TW
9,000 Ibs. Straight Line Pull
2'' Receiver Tube
RV Receiver Hitches

RV Receiver Hitches

3,500 - 5,000Ibs. GTW
300 - 500 Ibs. TW
3,500 - 6,000Ibs. WDTW
350 - 600 Ibs. WDTW
2'' Receiver Tube
Bumper Styles
Bumper Styles
Passenger Car & Truck Styles
Passenger Car & Truck Styles
Wiring Systems

CURT Manufacturing electrical products are designed to deliver unsurpassed levels of performance, reliablity and durability. The use of surface mount technology (SMT) components is just one of the steps CURT has taken to achieve this. SMT components are the most up-to-date parts available for circuit designs. SMT components offer lower resistance, less heat generation and longer life cycles than more common, out-of-date, through-hole mounted components.

CURT applies SMT to a full line of taillight converters and to any T-Connector with a built-in converter.

2 Wire Systems

Still common in the automotive industry and the simplest form of trailer wiring. This system sends the stop/turn signal along one wire, while the tail signal is separate.

3 Wire Systems

Still common in the automotive industry and the simplest form of trailer wiring. This system sends the stop/turn signal along one wire, while the tail signal is separate.
2 Wire System 3 Wire System

PWM Systems

More and more vehicles on the market today use PWM (pulse width modulation) wiring systems, sometimes called "multiplex" systems. These are systems that vary the signal intensity over one wire to initiate more than one lighting function. In other words, one wire can control more than one light function. There are two known types, type STT (Stop/Turn/Tail) and type ST (Stop/Tail). PWM systems can be either incandescent or LED.

SST Systems

They use a single wire to control the stop, tail and turn signals. For SST Systems use CURT tail light converter 56201.

ST Systems

They use a single wire to control the stop and tail signals. Separate wires are used to control the left and right turn signals. For ST systems use CURT tail light converter 56200.
SST System ST System
Wiring Harness Location Guide

Passenge Cars (P)

Wiring positions for passenger cars are represented by the letter P

  • P1-Behind driver's side tailight housing, outside of trunk
  • P2-Behind passenger's side tailight housing,outside of trunk
  • P3-Behind driver's side tailight housing,inside of trunk
  • P4-Behind passenger's side tailight housing,inside of trunk
  • P5-Behind driver's side rear bumper
  • P6-Behind center side rear bumper
  • P7-Behind passenger's side rear bumper
Passenge Cars (P)

Pickup Trucks (T)

Wiring positions for passenger cars are represented by the letter T

  • T1-Behind driver's side tailight housing
  • T2-Behind passenger's side tailight housing
  • T3-Behind driver's side rear bumper
  • T4-Behind centre of rear bumper fascia
  • T5-Behind passenger's side rear bumper
Pickup Trucks (T)

SUVS, Mini & Full-Size Vans (S)

Wiring positions for passenger cars are represented by the letter S

  • S1-Behind driver's side tailight housing
  • S2-Behind passenger's side tailight housing
  • S3-Behind driver's side rear access panel
  • S4-Behind passenger's side rear access panel
  • S5-Behind driver's side rear bumper
  • S6-Behind center rear bumper
  • S7-Behind passenger's side rear bumper
  • S8-Under rear floor panel
SUVS, Mini & Full-Size Vans (S)