Trailer

There are two ways to increase the lift when using a UBL system.
   Option 1: Increase Ride Height

• Refer to Hendrickson Literature No. L801 Liftable Application Guide for instructions. 

   Option 2: Convert to a Hendrickson low-ride suspension, if possible.

• If currently using a Hendrickson top-mount suspension consider switching to a Hendrickson low-ride suspension, to help provide more lift when using a UBL system.  
• Remember, the original manufacturer of the trailer should be contacted for approval and recommendations before making any modifications to the trailer. 

For additional assistance regarding specific trailers or applications, contact the Hendrickson Trailer Commercial Vehicle Systems product engineering department in the United States at 866-RIDEAIR (743-3247), in Canada at 905-789-1030 or in Mexico at +52 (442) 296-3600.

Start with choosing products that offer good corrosion-resistant coatings. 
 
Second, work with the component supplier to determine the proper coating cleaning and maintenance specifications, and implement a cleaning/maintenance schedule to extend the life of the coating. 
 
Regular inspections will also help to identify corrosion issues early enough to address the issue before it becomes a bigger problem.
 

Converting from current version of TIREMAAX CP (hubcap-mounted rotary union) to TIREMAAX PRO – You will need to replace the CP controller and hubcaps with PRO versions.Axle components, tire hoses, indicator lamps, manifolds and harnesses are compatible between PRO and CP, and the same axle drillings are used for both.
 
Converting from original version of TIREMAAX CP (spindle-mounted rotary union) to TIREMAAX PRO – You will need to replace the CP controller and all wheel-end components (hubcaps, tire hoses, axle hoses, axle vent, spindle plugs) with PRO versions.Indicator lamps, manifolds and harnesses are compatible between PRO and CP, and the same axle drillings are used for both.
 
Converting from TIREMAAX EC to TIREMAAX PRO – You will need to replace all components with PRO versions.
 
Refer to Hendrickson Literature No. L878 TIREMAAX Parts List for specific replacement part numbers and T51002 TIREMAAX Technical Procedures for instructions on installation, service and troubleshooting.

All air suspensions will drop down away from a loading dock while the trailer is being loaded.  Some suspension designs will also move away from the loading dock as the suspension drops down.  This movement away from the dock can be repetitive, causing the trailer to “walk” away from the dock.
 
Trailer drop can only be eliminated with the addition of a mechanism that reduces the amount of downward movement, like Hendrickson’s SURELOK® system.  Typical designs include a set of supports or legs that rotate into position above the suspension beams, preventing the trailer from dropping down onto the air spring bumpers.  These designs are usually automatically engaged, eliminating the need for trailer operator involvement.   Limiting the vertical movement of the trailer also prevents the trailer from moving away from the dock.
 
If trailer drop is not a concern, trailer walk can be addressed by exhausting the air from the suspensions before loading the trailer.  Various suspension “dump” valve arrangements are available for addressing each application.  Proper use of the suspension dump valve will eliminate trailer walk while allowing the trailer to drop, but they typically require some interaction from the trailer operator.

No.  Reduced Stopping Distance regulations only apply to tractor and truck units, not the trailer.  In fact, using an overly aggressive lining, like some linings used in RSD systems, may cause the trailer brakes to lock up faster because of weight transfer in a panic stop.

Both TIREMAAX PRO and CP models are set to a specified target pressure for inflation. As long as the pressure in the trailer air tank is above the target pressure, the TIREMAAX controller will continuously supply and maintain tire pressure at target.
 
For TIREMAAX PRO, all check valves or wheel valves are open to allow air flow in both directions, equalizing pressure across all wheel positions.  PRO also has the ability to relieve pressure from over-inflated tires.  The relief pressure is set at 10 psi above the cold target pressure.  If tire pressure goes above this setting, the TIREMAAX PRO controller will exhaust air and maintain pressure at the preset relief value.

No.  Brakes should be chosen based on the highest required load and no higher.  For instance, hub, suspension, axle and tire ratings may all differ on a given trailer, ranging from 17,000 to 26,000 pounds or higher depending on the trailer application. 
 
However, it is the minimum rated component of this group that determines the gross axle weight rating (GAWR), and brakes should be sized according to the GAWR. 
 
Using an overrated brake lining on your application can lead to excess brake torque which can result in tire wear, brake wear, noise and trailer hop.   

When converting from a spring or another supplier’s air suspension to a Hendrickson trailer air suspension, please consider the following items:

• Contact the OEM - The original manufacturer of the trailer should be contacted for approval and recommendations before making any modifications to the trailer.
• Suspension Choice - Refer to Hendrickson Literature No. L707 Application Guide for assistance in spec’ing the appropriate Hendrickson aftermarket air suspension.
• Trailer Crossmembers for Suspension - Hendrickson suspensions require crossmembers in the trailer frame or sub-frame at specific locations.These crossmembers are shown on the Hendrickson installation drawings included on the literature page of www.hendrickson-intl.com.  Please contact the trailer OEM for any required crossmembers or other related parts that may need to be installed as part of converting to a Hendrickson air suspension, and for its approval and recommendations before making any such modifications to the trailer.
• Axles - The existing axles cannot be reused with a Hendrickson air suspension. The axle wall thickness used with spring suspensions is not typical for use with trailing beam air suspensions that are welded to the axle. Additionally, camshaft lengths and brake chamber locations may not provide appropriate clearance.
• Air Controls - An air suspension must be operated at the correct ride height and must be provided with reliable air supply. The simplest means to accomplish this is the use of a single Hendrickson height control valve. To select the appropriate HCV kit, refer to Hendrickson Literature No. L1182 Controls Parts Catalog.

Please refer to Hendrickson Literature No. L388 - Ride Height Settings for your designed height, minimum height, and maximum height per your suspension model.

You can find your brake ratings on Hendrickson Literature No. L809 Consolidated Certificate of Compliance for Air Actuated Brakes