Jump to content

Unstable over bumps

derek01f
 Share

Recommended Posts

derek01f Enthusiast

derek01f

Posted
Posted

I've noticed my truck is very unstable when going over bumps on the road, doesn't really matter my speed, but the truck becomes very "loose".  Anybody else notice this?

  • Replies 45
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

Gangly
Gangly

Its a truck guys, they are designed to work meaning they are engineered to perform tasks associated with hauling loads in the bed, trailer, etc.  By default, they will perform best with a little weigh

newdude
newdude

Put 200lbs in the bed and re-test.  If you think a 1500 does it, try a 2500HD empty over the same road. 

Rob41
Rob41

It's not just the Z71 and max tow packages.  I have the RST non-Z71 and like previous pick-ups it too fishtails on washboard roads.  Unfortunately this is the worst I've ever seen and I buy a new chev

Posted Images

Sierra Dan Senior Enthusiast

Sierra Dan

Posted
Posted
31 minutes ago, derek01f said:

I've noticed my truck is very unstable when going over bumps on the road, doesn't really matter my speed, but the truck becomes very "loose".  Anybody else notice this?

Do you have Z71 suspension package with the Rancho shocks?

What trim package if so? Trail Boss or other?

derek01f Enthusiast

derek01f

Posted
  • Author
Posted
1 minute ago, Sierra Dan said:

Do you have Z71 suspension package with the Rancho shocks?

What trim package if so? Trail Boss or other?

2019 RST Z71 Crew Cab Reg bed.  Yes, I believe they are Rancho shocks.

Sierra Dan Senior Enthusiast

Sierra Dan

Posted
Posted (edited)

Well IMHO as I have stated before in the 2014-2018 truck section, it is the Rancho shocks.

Trail Boss and AT4 are equipped with the Monotube version which is better than the twin tube design on your truck.

Twin Tube Ranchos are not dampened very well and are lackluster on roads where there are railroad crossings, pot holes, washboard sections etc.

They are also spongy and the rebound is off when off roading.

 

Edited by Sierra Dan
  • Like 1
aseibel Senior Enthusiast

aseibel

Posted
Posted
47 minutes ago, derek01f said:

I've noticed my truck is very unstable when going over bumps on the road, doesn't really matter my speed, but the truck becomes very "loose".  Anybody else notice this?

Please tell us about your tire size, air pressure, etc.

Lower profile tires and over-inflation will make the ride worse no matter what shocks you have. Trucks do ride rougher when completely unloaded.

derek01f Enthusiast

derek01f

Posted
  • Author
Posted (edited)

Fresh from dealer when I brought it home the truck had 41psi in each tire, I took that down to recommended level, right around 35

 

I also put new tires on the truck and it does the same, these tires are Cooper Discoverer AT3 XLT - 275/70/18

updated-pics.jpg

Edited by derek01f
  • Like 1
Wiggums Senior Enthusiast

Wiggums

Posted
Posted

It's been discussed here. I got flamed when I mentioned that!

That's why I have ten on my ignore list. The back end fishtailed so badly I nearly ran over a guy on the side of the road. It was a straight road with dried dirt on top from a recent storm. I was so surprised it fishtailed when I wasn't hitting the gas or braking on a straight road.

 

Solution: the tires were inflated at 45 psi or 44, well above the recommended 35. I have no idea why it came like that and letting air out helped a bit. The next two times, it fishtailed but wasn't as bad as the first one. I was so mad, I nearly ran over a pedestrian. Like you, I have an RST 4x4 so I know exactly where you're coming from.

Cooper 114 Enthusiast

Cooper 114

Posted
Posted

I was doing around 80km/h and hit a washboard area in the road.  The truck began to yaw and was nearly sideways before I was able to recover it.  Stabilitrak never kicked on. Road was dry.   Bounce was so bad the tonneau cover actually detached and landed on the road.  I have the max trailering package so the suspension is tight to begin with.  Scared the hell out of me for sure.  Bumps, potholes and train track crossings are rough but not to the point of losing control like the washboard area did.  Never experienced anything like it in my past GM pickup trucks.

Rob41 Enthusiast

Rob41

Posted
Posted

It's not just the Z71 and max tow packages.  I have the RST non-Z71 and like previous pick-ups it too fishtails on washboard roads.  Unfortunately this is the worst I've ever seen and I buy a new chevy every three to four years.

 

Like others have said, adding weight to the back will help but it's not going to go away completely.  Bilstien 5100 shocks also help but there is no real solution.  Heavy springs designed for the payload/ towing wars combined with a now lighter weight back end means more fishtailing.

  • Like 2
Bluerado23 Enthusiast

Bluerado23

Posted
Posted
Welcome to the Z71 T1 walking rear end club. 
 
You're not alone, fellow Rancho victim. Lol


Well I’m kinda glad to see it’s more than one person. Crappy problem to have, I noticed it early on and no matter what I have done, wheels/tires or different air pressures it all reacted the same way.

Shocks are on top of the mod list right now. I’m waiting for fox to release a 2.0 coil over good for two inches of lift so I can do something like a trail boss setup
econometrics Senior Enthusiast

econometrics

Posted
Posted
8 minutes ago, Bluerado23 said:

 


Well I’m kinda glad to see it’s more than one person. Crappy problem to have, I noticed it early on and no matter what I have done, wheels/tires or different air pressures it all reacted the same way.

Shocks are on top of the mod list right now. I’m waiting for fox to release a 2.0 coil over good for two inches of lift so I can do something like a trail boss setup

 

Fox coil overs will most certainly help smooth things out. 

 

Mostly, this is just the result of trucks getting lighter, but able to carry more payload. Stiff rear ends when empty. 

  • Like 1
Wiggums Senior Enthusiast

Wiggums

Posted
Posted
3 hours ago, Cooper 114 said:

I was doing around 80km/h and hit a washboard area in the road.  The truck began to yaw and was nearly sideways before I was able to recover it.  Stabilitrak never kicked on. Road was dry.   Bounce was so bad the tonneau cover actually detached and landed on the road.  I have the max trailering package so the suspension is tight to begin with.  Scared the hell out of me for sure.  Bumps, potholes and train track crossings are rough but not to the point of losing control like the washboard area did.  Never experienced anything like it in my past GM pickup trucks.

 

Exactly the same situation I was in. That is a liability issue, I was more angry over the fact I could have killed the guy walking on the side of the road. GM fanboys got all over me on this, questioning my experience, etc. "My Ford did the same" I've driven 4x4's and none were this bad. I was going about 70 km/h, maybe 80 km/h when it happened. That is why my next car isn't going to be a Chevrolet unless they address this.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.5k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,958
    Total Members
    8,960
    Most Online
    B07
    Newest Member
    B07
    Joined

  • Who's Online   0 Members, 0 Anonymous, 876 Guests (See full list)

    • There are no registered users currently online

  • Latest Articles

  • Posts

    • Grumpy Bear
      Some Assembly is Required

      By Grumpy Bear · Posted

      Missing pieces of the Assembly   Detergency vs Solvency   Not the same thing. Detergency is the mechanism that surrounds solid particulates preventing amalgamation. Usually accompanied by a Dispersant whose job it is to keep those encapsulated particles in Suspension. Solvency keeps things that can be dissolved in solution.    Salt is a solid that can be dissolved. Pepper is a solid that cannot be dissolved. A detergent/dispersant is effective on pepper but a solvent is more effective on salt. As long as the solids remain in either state, dissolved or dispersed then they can be be removed with the oil upon change.    How many wranglers does it take to herd cats? Depends on how many cats your herding. How much sponge does it take to soak up water? How much water is there to soak up? Point is most oil blends start with some herding ability and next to zero sponge and recently even fewer wranglers are being sent to do the same job.    So you start with a dozen cowboys and zero cows but at the drive progresses you pick up cows along the way, but not cowboys. At some point you have more cows that the wranglers can handle and some leave the herd. Deposits. And the API has an acceptable number of cows they are willing to let loose. In the ideal world zero is the right number for he rancher but to the butcher....a few lost is fine. This cow is beat to death. Let's move on....   Solvency isn't something oils on the Walmart shelf care about AT ALL. Problem is, you motor does. Fuels driven varnish sticks rings and only a solvent can keep them in check. The bet is that the solids driven portion that plug the expander rings and the oil drain backs and VVT screens and AFM screens will be an issue long before varnish is. Not that it wont be but if they market well enough the consumer can be kept ignorant enough to either believe it is "normal" (A quart in 1 or 2K is normal) OR is kept at bay longer than the first owner is likely to hang on to the unit. Solvency cost money.    Now the OEM's have John Q. Public buffaloed into the belief that the number cows accumulated along the trail is a known and predictable CONSTANT. It isn't. Nor is the rate at which they crossed paths with them. Only the number of wrangles is constant. Or was. Each new generation of oil sees fewer and fewer of them.    So what happens when the number of cowboys is lower (lower TBN) with each seasons trail but the trial is longer (OCI) and the number of cows along that trail continues increase? (Conditions that promote deposits).    For awhile the blenders were on to something. Better bases are harder to degrade (fewer cows) but that was overtaken by a longer trail (OCI) and improved breeding (More cows) while continuing to reduce the cowboy staffing levels (TBN/Aniline #).    Marketing has been successful. We've fired most of the staff, cows breed line bunnies, the trail is ten times longer and we've convinced the boss his ranch is in better shape that it ever was.    That kids is just the cleaning side. The side few pay attention to.     
    • davester
      Needing this part.

      By davester · Posted

      hit a junkyard.
    • Z45
      PF63 Oil Filters Going Away?

      By Z45 · Posted

      Mann+Hummel since 1941 per their web site 
    • B07
      Needing this part.

      By B07 · Posted

      Looking for this part for my truck. They don't sell just that one piece and to get it you have to pay over $100 even used for the whole air tube. The piece the hose clamp snaps into that is held on by the screw and nut. If anyone has access to one please let me know.
    • rav3
      2017 Silverado Front Bumper Valence/license plate holder

      By rav3 · Posted

      https://ebay.io/m/cTI46i

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...