Tow Vehicle Suspension

[Davadar]

Our 2008 GMC 2500HD is starting to sag in the rear and bounce quite a bit when hitting bumps. We're thinking about adding an extra leaf spring and replacing the shocks with Bilstiens. Would there be any issues with adding the extra spring and what would our other options be? The dog box on the back of the truck weighs about 1000 pounds.
Thanks Dave

[SteveH]

It looks level enough so I would replace the shocks first and see how that helps.

But, what is all that weird looking white stuff?

[RickDavis]

I added after market helper springs to my 99 Dodge 2500 although air bags might be an option worth looking at also.
I also put on Bilstein shocks at the same time. That was half million miles ago and as far as I can tell the shocks are still good.
I carry a lot of extra weight, tools extra fuel etc and was also moving a lot of heavy trailers at the time .
If you run without your dog box it may ride a bit stiffer but that is a trade off to be expected. Air bags would let you compensate if need be, but then springs don't leak

[SteveH]

You might also consider some Timbren helper springs. Lots simpler, cheaper, and won't effect the ride when you are empty.

[Davadar]

The picture of the truck is from last January and the dog box is never taken off.
I was at the local spring shop today and asked about the Timbren spring which they sell and was told that they would only be a benefit when the truck was heavily loaded. With just the dog box they would be smacking against the axle whenever I hit a bump.
Dave

[3campers]

Been there done that...new shocks will damper your bounce then consider helper suspension air bags... they work awesome! Best part, you can install them yourself. Here's a link to get you started... Suspension Air Bags, Air Helper Springs, Air Spring Kits

[Denis4x4]

I put Firestone air bags on my '06 GMC 2500HD so that I could use a 2100 pound camper along with the AS. It's an easy install and unlike helper springs, you can adjust the air pressure to fit your needs when towing.

[slowmover]

What is your adjusted empty weight of the truck in comparison to the published weight, and against the weight of the truck when new? (Full fuel + driver and permanent items aboard for the solo weight for the latter, and when loaded for camping for the former; the additional weight).

Air bags don't distribute the weight across the length of the spring but only at midpoint. A truck using WDH needs that device dialled in on a scale, first, before considering suspension alterations which can adversely alter the best handling/steering of the truck.

Aeon Springs (Timbren). Call them with your concerns as they guarantee to work with you. The spring shop isn't "wrong", per se" in their comment, but they may also not have considered that catalog part numbers don't make a cut-and-dried situation. Some other part numbers may work.

I would add a spring leaf before air bags or other. Better, replace the spring pack altogether with a set which more accurately represents the permanent load (the reduced range of loading).

Getting the WDH dialled in, first, is the first step. TV tire pressure is second. Then, comparing measurements to the truck when new to determine actual spring settling can be done. Some dimunition of height is not itself bad, it would be in spring action that concerns would arise.

BILSTEIN is a good shock absorber choice. KONI FSD would be better yet. See, and contact, HENDERSONS LINEUP for more.

.

[Davadar]

Thanks Slowmover. Now I'm really confused but that's good maybe I'll learn something. I don't know the weight of the truck or how to go about weighing it. I will contact Can-Am RV about fine tuning the hitch, they set the hitch up when we bought the trailer.
We added a leaf spring, installed the Bilstien HD shocks and replaced a broken spring. The truck is almost 2" higher now.
I wish I had known about the Koni shocks earlier.