Most commercial heavy-duty truck trailers are equipped with either a two sensor, one modulator (2S1M) or four sensors, two modulator (4S2M) anti-lock braking system (ABS). Previous research has been performed comparing the performance of different ABS modules, in areas such as longitudinal and lateral stability, and stopping distance. This study focuses on relating ABS module type and wheel speed sensor placement to trailer wheel lock-up and subsequent impact to tire wear for tandem axle trailers with the Hendrickson air-ride suspension. Prior to tire wear inspection, functionality of the ABS system was testing using an ABS scan tool communicating with the SAE J1587 plug access port on the trailer. Observations were documented on trailers using the 2S1M system with the wheel speed sensor placed on either the front or rear axle of a tandem pair. As a result of wheel lock-up and subsequent flat spotting; the compromised wear pattern propagates throughout the tire rapidly due to high trailer loads. From observed trends in the collected information it has been determined that tire wear from flat spotting due to wheel lock-up tends to occur on the axle opposite of sensor placement. Therefore, it is the recommendation of this study only anti-lock brake systems with four wheel-speed sensors and two modulators (i.e., 4S2M) are used in applications involving Hendrickson air-ride heavy-duty truck trailers. Such a configuration will reduce overall skid wear of the trailer tires improving truck and trailer safety while reducing the financial impact from pre-mature tire replacement.