Sharp Bouncing

rider997 wrote:

jeffreyduncan wrote:
Morning.

I have a 2015 Chevy 3500 HD short bed, Crew with the duramax. It's setup with RS9000's in the rear (set at 9) and stable loads. Front shocks are Bilstein 5100. I have a Hellwig stabilizer in the rear. Truck is stock otherwise. No airbags.

I have a fairly heavy camper and took this setup out over the weekend for my first road trip. Everything went very well and I am generally pleased with the way it handles. However - I notice that I get an annoying fast bounce (I think from the rear). It's not a porpoise. It's more of a chucking. It happens a couple times per second it seems, when I am rolling over small bumps at highway speeds or over 40mph. It's not constant, and any larger bumps or dips are handled fine. It's more of an annoyance than a drivability issue.

I am thinking it's because my auxiliary springs are so pre-loaded with the stable loads. They are almost flat, but they aren't so flat that they touch the lower springs. i have maybe and inch and a half left. The truck sits nice and level though.

Would anyone have a suggestion to calm the sharp bounce and improve the ride?

I was thinking my options might be:

Add air bags.
Change the Bilsteins in the front for RS9000.
Install stiffer rear aux springs (SuperSprings).

Any insight would be appreciated.

I have the same truck and camper as you, except that I have the 6.0 instead of the DM. I also have a Hellwig big wig adjusted to max. I disconnect the sway bar when the TC is not loaded to return some articulation to the suspension.

FWIW, you want the Bilstein 4600 series shocks, not the 5100s.

I have Bilstein 4600s on all four corners, and they're a definite improvement over the stock "fake" Ranchos.

It sounds like you have lower Stableloads? I went with the uppers to avoid what it sounds like you're talking about - the sudden engagement of the upper overload leafs when you hit a bump. With the upper stableloads, all leafs are engaged at all times with the TC loaded. I find the loaded ride to be surprisingly good. My only ride issues are hitting large potholes offroad while off camber. Even with upgraded shocks and a sway bar, it sets up a momentary oscillation that can be disconcerting.

Being that we have essentially the same setup except for (as I suspect) the type of Stableloads installed, I would put money on it being the aggressive net spring rate change from the engagement and disengagement of the upper overload leafs.

My main problem right now is the one you mentioned with the rubber bumpers not engaging the front of the bulkhead. I'm thinking about having some 1" UHMW PE spacers cut to install behind the rubber bumpers.

Thanks. I actually have the upper stable loads which instantly engage the overloads. The overloads are nearly flat when I am loaded. I just ordered some 4600's for the front and will try those.

I have the standard Hellwig. How are you adjusting it? Just cranking the threaded link in a bit more? I think I have about 3" from nut to center of the bottom bolt hole. I'd need to put some pressure on the bar to tighten those any further. I simply snugged them up best I could by hand. There was no adjustment procedure in the box. I probably could get more out of it if I tightened the links down I guess.

How are you disconnecting it without removing the whole thing?

Have you weighed your rig yet?