Selection Guide
Match your trailer coupler to one of the images below and follow the instructions for that coupler to determine which trailer coupler lock is best for your trailer.
This is one of the most common types of trailer coupler in the market today. There are many manufacturers for this type of coupler and each manufacturer can change the external features without affecting the fit to the trailer hitch ball. To ensure you receive the proper coupler lock for your trailer, follow these guidelines.
Refering to the image at the right. Measure from the end of the coupler back 3 1/2" , at that point measure across the width of the coupler as indicated by dimension "C". If that measurement is less than 3 7/8" the BT2 coupler lock will fit your coupler. If your measurement is larger than 3 7/8" but smaller than 4 3/8" the BT1 coupler lock will fit your coupler. Ball size with this style of coupler is not a determining factor for lock selection.
This is one of the most common types of trailer coupler in the market today. There are many manufacturers for this type of coupler and each manufacturer can change the external features without affecting the fit to the trailer hitch ball. To ensure you receive the proper coupler lock for your trailer, follow these guidelines.
Refering to the image at the right. Measure from the end of the coupler back 3 1/2" , at that point measure across the width of the coupler as indicated by dimension "C". If that measurement is less than 3 7/8" the BT2 coupler lock will fit your coupler. If your measurement is larger than 3 7/8" but smaller than 4 3/8" the BT1 coupler lock will fit your coupler. Ball size with this style of coupler is not a determining factor for lock selection.
Collar-Lock style couplers
This is a collar-lock type of trailer coupler. There are several manufacturers of this type of coupler such as Bulldog, and Fulton. Manufacturers can change the external features without affecting the fit to the trailer hitch ball. To ensure you receive the proper coupler lock for your trailer, follow these guidelines.
Refering to the image at the right. Measure from the end of the coupler back 2 1/2", at that point measure across the width of the coupler as indicated by dimension "C". That measurement must be less than 4 3/8". Now measure the coupler for dimension "D". If your measurement is 3/4" or smaller, you will need a BT1 coupler lock. If your measurement is larger than 3/4" and up to 1 3/8" you will need the BT3 coupler lock. The 2" ball size of this style hitch will also work with the BT4 coupler lock which will provide a closer fit to the coupler.
This is a cast iron trailer coupler. There are several manufacturers of this type of coupler such as Curt, and Yeopgyeon. Manufacturers can change the external features without affecting the fit to the trailer hitch ball. To ensure you receive the proper coupler lock for your trailer, follow these guidelines.
Refering to the image at the right. Measure from the end of the coupler back 3 1/2" , at that point measure across the width of the coupler as indicated by dimension "C". That measurement must be less than 4 3/8". The BT1 coupler lock will fit this trailer coupler.
Auto-Latch style couplers
These represent a big variety of Auto-Latch style couplers. There are several manufacturers of this style of coupler, offering cast iron and stamped steel construction. To ensure you receive the proper coupler lock for your trailer, follow these guidelines.
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Referring to the image at the right. Measure the "C" dimension, if it is less than 2 7/8" and the "D" dimension is less than 7/8" the BT6 coupler lock will fit your trailer.
BT1 Coupler Lock
BT1 coupler lock is primarily designed to work with the 2 5/16" hitch ball size and it will work with a wide variety of coupler types including 2" couplers as well. The following guidelines will help you determine if the BT1 will work for you. The cavity dimensions for this lock are 2 3/4" high x 4 3/8" wide x 3 3/4" depth. The depth dimension indicates how far the coupler travels into the lock. No part of the coupler can exceed the width dimension for the length of the depth dimension. Dimension "D" cannot exceed 7/8". If your trailer coupler fits within these dimensions the BT1 fits your needs.
BT2 coupler lock is primarily designed to work with 1 7/8" and 2" hitch ball size and it will work with a wide variety of coupler types. The following guidelines will help you determine if the BT2 will work for you. The cavity dimensions for this lock are 2 7/16" high x 3 7/8" wide x 3 3/4" depth. The depth dimension indicates how far the coupler travels into the lock. No part of the coupler can exceed the width dimension for the length of the depth dimension. Dimension "D" cannot exceed 7/8". If your trailer coupler fits within these dimensions the BT2 fits your needs.
BT2 Coupler Lock
BT3 coupler lock is primarily designed to work with 2 5/16" hitch ball size and it will work with a wide variety of coupler types. The following guidelines will help you determine if the BT3 will work for you. The cavity dimensions for this lock are 2 3/4" high x 4 3/8" wide x 3 3/4" depth. The depth dimension indicates how far the coupler travels into the lock. No part of the coupler can exceed the width dimension for the length of the depth dimension. Dimension "D" cannot exceed 1 3/8", if dimension "D" is less than 7/8" use BT1 coupler lock. If your trailer coupler fits within these dimensions the BT3 fits your needs.
BT3 Coupler Lock
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BT4 coupler lock is primarily designed to work with 2" hitch ball size Collar-Lock style couplers. The following guidelines will help you determine if the BT4 will work for you. The cavity dimensions for this lock are 2 7/16" high x 3 7/8" wide x 3 3/4" depth. The depth dimension indicates how far the coupler travels into the lock. No part of the coupler can exceed the width dimension for the length of the depth dimension. Dimension "D" cannot exceed 1 3/8". If your trailer coupler fits within these dimensions the BT4 fits your needs.
BT4 Coupler Lock
BT5 Coupler Lock is designed to fit a 5th Wheel coupler with a 2" king pin. This lock will work with or without the bearing disk installed on the King Pin. The inside dimensions of the lock is designed to fit over a 2 7/8" king pin base.
BT5 5th Wheel Coupler Lock
BT6 Coupler Lock
BT7B Coupler Lock
BT7D coupler lock is primarily designed to work with Dexter 2" &
2 5/16" hitch ball size couplers with surge brakes. The following guidelines will help you determine if the BT7D will work for you. The cavity dimensions for this lock are 3 1/4" at back tapering to 2 1/4 " at front x 3 1/4" wide x 3 3/4" depth. The depth dimension indicates how far the coupler travels into the lock. If your trailer coupler fits within these dimensions the BT7D fits your needs.
BT7D Coupler Lock
BT7E Coupler Lock
