Which is better: Helper Springs or Add-a-leaf? | Timbren SES

Which is better: Helper Springs or Add-a-Leaf?

In order to compare a helper spring with an add-a-leaf product, we’ll need to agree on a definition for each one before we get started. (That way, we’ll be singing out of the same hymn book!) First of all:


  1. Let’s agree that when we say ‘helper spring’ we’re talking about upgrades for trucks that bolt on to either the frame or the axle replacing the factory bump stops.


  1. Let’s agree that by ‘add-a-leaf’ (AAL) we’re referring to a metal product that bolts on to the existing leaf spring suspension.


  1. Let’s agree that, in either case, we’re assuming your truck has a conventional leaf-spring suspension from the factory.


Now, we can begin our comparison between a helper spring and an add-a-leaf product.


If you were to Google “add a leaf,” you would see the many different companies that offer this type of product. So, to simplify our discussion, let’s restrict our comparison to the following two products: Timbren SES suspension upgrades and Hellwig EZ-990 Helper Spring Kit.


Timbren SES Leaf Spring 

What are the similarities between a Timbren SES and a Hellwig EZ-990 Helper Spring Kit?


Both Timbren SES and Hellwig EZ-990 helper springs...

  1.  Provide additional lift
  2. Prevent sagging and squatting
  3. Stabilize the load
  4. Prevent body roll
  5. Install easily
  6. Cost under $300.00
  7. Offer a Lifetime Warranty
  8. Require very little maintenance


What are the differences between a Timbren SES and a Hellwig EZ-990 Helper Spring Kit?


  1.  The first – and obvious – difference between the 2 products is the material: The Hellwig EZ-990 helper springs are made of tempered steel; Timbren SES upgrades are made of natural rubber.
  2. The second – and not-so-obvious – difference between the 2 products is their spring rate: Hellwig metal springs have a linear spring rate (i.e., the metal springs deflect at the same rate all the way to full deflection). On the other hand, SES hollow rubber springs have a progressive spring rate (i.e., the spring rate of the rubber springs increases as they deflect right down to full deflection).
  3. The maximum additional load capacity of the Hellwig EZ-990 = 2,000 lbs. designed for lighter assistance. On the other hand, SES upgrades = 12,000 lbs. designed for heavier assistance.


hellwig helper spring


How do I install a Hellwig EZ-990 Helper Spring Kit?


The following is taken from a Hellwig EZ-990 instruction sheet:


1. Place the spring on top of the mainspring with the long end toward the rear of the vehicle.


2. Slide the spring back and forth so the hump doesn’t touch the factory vehicle U-bolts but to maximize the distance between the leaf tips and the underside of the vehicle.


3. Place the U-bolts with the short legs on either side of the hump as shown in the diagram. Using the included cross bars, washers, and nuts, tighten to the recommended torque. 


4. Use the longer legged U-bolts on the outside cups of the spring as shown in the diagram. Attach them once again using the crossbars, washer, and nuts. It may be necessary to either jack the vehicle up by the frame allowing the suspension to droop or use a C-clamp to compress the spring to start the nuts.


5. Adjust the crossbars on the end of the springs so that the adjacent leaf tip will not contact the crossbar when the spring is deflected. It may be necessary to move the spring stack fore or aft for best alignment.


6. Adjust the U-bolts at the spring end to desired preload. The minimum tension adjustment is having enough tension on the end U-bolts so that they do not loosen or rattle and move when the vehicle is driven over rough or bumpy surfaces. Maximum adjustment is when the leaf cups are 1/4” from the main spring.


7. When adjustment is complete, double-nut to lock in adjustment.


8.Lower the vehicle to the ground and check your installation for clearance on all undercarriage components; wires, fuel, brake, and air conditioning lines. 


     With the right tools, a first-time installer could take up to 2 hours.


How do I install a Timbren SES upgrade?


*This following instructions represent a typical SES installation:


After partially lifting the back end of your truck, remove the factory bump stops located on the frame just above the axle.


While the truck is still lifted, assemble metal bracket, spacers, supplied fasteners and Aeon® rubber spring in their proper order as shown in the instructions. Bolt the kit assembly to the frame.


After lowering the truck to the ground, measure the gap between the bottom of the rubber spring and the top of the axle, making sure there is at least a half inch but no more than 1.5 inches of space.


A first-time installer will spend somewhere between 30 - 60 minutes.



Why would you choose Timbren SES over a Hellwig add-a-Leaf?


If you have taken the time to read through the above report, you’ll know there are many similarities between a Timbren SES upgrade and a Hellwig EZ-990 Helper Spring Kit.


However, there is one major difference: Capacity.


The Hellwig Add-a-Leaf product described in this short report is meant to provide lighter assistance for lighter loads, maxing out at 2,000 lbs additional capacity – mainly because of the linear nature of its metal springs.


Timbren SES upgrades, on the other hand, offer up to 12,000 lbs additional capacity due to the progressive nature of its hollow rubber springs.


Q. Why would you choose Timbren SES upgrades over Hellwig’s add-a-leaf?

A. To gain a lot more capacity!


For more information on Timbren SES upgrades, click here.