Rear-End Sag in 2004 Silverado 2500 4X4 Crewcab With Weight Distribution System Installed

Question:

I am pulling a 7,500 lb. trailer with standard 2 in. receiver hitch. I have weight distribution bars attached. I still have significant back end sag of the truck. This truck is 2500 only, not HD. What cost affective product can I install on the rear suspension to help with the sag? Thank you.

asked by: Doug C

Expert Reply:

The best way to fix rear-end sag when towing your 7500-lb trailer with your truck is to use a weight distribution (WD) system. Rear axle suspension helper kits, such as Timbren jounce springs or air bag kits, are better for times when you are carrying a heavy cargo load in the truck bed. These will not give you the same benefits as a properly-tuned WD system when towing a trailer. In fact, if jounce springs or air bags are used along with WD, then they can sometimes interfere with each other and lead to odd handling.

Tongue weight (TW) is the single most important factor when choosing a WD system, and if the spring bars on your system are not stiff enough for your actual TW, or if they are not adjusted correctly, this can result in less weight being pushed forward onto the front axle. This can lead to rear-end squat.

You might want to confirm your loaded trailer tongue weight to ensure your current spring bars are rated correctly. The linked article explains ways to measure, including a tongue weight scale # e99044 from Sherline. To the fully loaded trailer tongue weight you need to add the weight of anything in the vehicle that sits behind the rear axle, such as a generator or loaded cooler. With this total effective TW figure known you can choose appropriately-rated spring bars.

We may have higher-rated spring bars that will fit your brand and type of system. For example, Reese Strait-Line Weight Distribution system # RP66074 comes with spring bars rated for 600- to 1200-lbs of TW. It works best with a TW in the middle of that range - say 900-lbs. If you had this or a similar system you could try increasing the tension on the bars so long as your TW is still within the operating range. If you found that you needed heavier spring bars you can let us know the part number of your system.

Please feel free to let me know your total effective TW and the brand and part number for your hitch and I will be glad to check for heavier bars if that is indeed what is called for.

expert reply by: Adam R