Today's Trucking
products Brakes Other


Posted: August 1, 2014

If you thought you couldn’t get a stability ‘enhancement’ system for your spring-suspended trailers, Meritor WABCO has an answer for you. The joint venture between ArvinMeritor ( and WABCO Vehicle Control Systems of Brussels ( says its independent stability enhancement system for trailers, RSSplus, is now available as an affordable retrofit kit whether you have air or mechanical suspension on your trailer(s).

RSSplus is part of the SmartTrac family of stability control products that also includes Electronic Stability Control (ESC), Roll Stability Control (RSC), and Automatic Traction Control (ATC).

It’s an advanced two-modulator stability setup that integrates with the trailer’s antilock braking system (ABS). It continually calculates the trailer’s roll stability threshold based on lateral acceleration (side-to-side movements) and individual wheel speeds. When an impending rollover is imminent, the system will apply the trailer axle brakes to slow the vehicle and assist the driver in maintaining control. The system can apply full brake force to the outside wheels while delivering lower pressure to the insides.

Different retrofit kits accommodate a wide range of braking system configurations, including 2-sensor/1-modulator (2S/1M), 2-sensor/2-modulator (2S/2M), and 4-sensor/2-modulator (4S/2M). The system can be installed on trailers equipped with Meritor WABCO ABS or a competitor’s product.

Installation involves replacing the ABS ECU/valve assembly with the RSSplus ECU valve assembly and mounting an electronic sensor to measure the defection of the suspension springs. If the trailer is equipped with Meritor WABCO ABS, existing wheel-speed sensors and cables can be reused to reduce the installation expense. A typical retrofit installation with mechanical suspensions takes approximately four to six hours.

RSSplus retrofit kits come with a comprehensive warranty of one year/100,000 miles, parts and labor. Cost is approximately US$1200, assuming the trailer already has ABS.

Note that this is a designed-for-North America system, not one adapted from European technology, that doesn’t require a power inverter to convert from 48 volts.


  • This field is for validation purposes and should be left unchanged.
Related Articles