Suspension hop on Interstate

[tflessner]

Can anyone help me with a suspension issue? I've got a 2003 Chevy Silverado 1/2 ton extra cab 4x4 that bounces on the interstate, but only on the highway that is poured with concrete? On the asphalt part, it is fine? It seems the concrete areas have some wavyness to them and the truck bounces, mostly in the rear?

 

I'm told there are some different rear end shackles I could put on called Velvet Ride Shackles. Or would different shocks help?

 

If anyone has ever had this problem and/or solved it somehow, let me know.

 

Any help/suggestions would be appreciated!

 

Thanks

[mmmikkke]

Can anyone help me with a suspension issue? I've got a 2003 Chevy Silverado 1/2 ton extra cab 4x4 that bounces on the interstate, but only on the highway that is poured with concrete? On the asphalt part, it is fine? It seems the concrete areas have some wavyness to them and the truck bounces, mostly in the rear?

 

I'm told there are some different rear end shackles I could put on called Velvet Ride Shackles.  Or would different shocks help? 

 

If anyone has ever had this problem and/or solved it somehow, let me know.

 

Any help/suggestions would be appreciated!

 

Thanks

 

<{POST_SNAPBACK}>

 

 

GM calls this "beam shake" and it may not be unique to GM. Because on an extended cab short box truck the rear axle is moved rearward relative to a regular cab truck, the axle is not in a balanced position relative to the frame rails. There's more weight on the frame in front of the rear axle than there is rearward of the rear axle. As a result, there is a natural frequency to the frame, and it will oscillate when excited by pavement joints if the frequency that the pavement joints are encountered at is close to the natural vibration frequency of the frame.

 

One solution I've heard is that if you put a couple of bags of sand at the very rear of your bed, that will help improve the balance forward and rearward from the axle, and it will lessen the "beam shake." I've never tried this but I'd be interested if anybody else has and what the results were.

[tflessner]

Can anyone help me with a suspension issue? I've got a 2003 Chevy Silverado 1/2 ton extra cab 4x4 that bounces on the interstate, but only on the highway that is poured with concrete? On the asphalt part, it is fine? It seems the concrete areas have some wavyness to them and the truck bounces, mostly in the rear?

 

I'm told there are some different rear end shackles I could put on called Velvet Ride Shackles.  Or would different shocks help? 

 

If anyone has ever had this problem and/or solved it somehow, let me know.

 

Any help/suggestions would be appreciated!

 

Thanks

 

<{POST_SNAPBACK}>

 

 

 

 

 

Thanks for the information, I appreciate it! I'll try the sandbags in the back and see how that solves the "beam shake". I'm going to put a class III tow/receiver in the back and put a larger tire on the spare rim (to match the 265's I have on now) so maybe that will help with a little more weight on the rear.

[diverlloyd]

Can anyone help me with a suspension issue? I've got a 2003 Chevy Silverado 1/2 ton extra cab 4x4 that bounces on the interstate, but only on the highway that is poured with concrete? On the asphalt part, it is fine? It seems the concrete areas have some wavyness to them and the truck bounces, mostly in the rear?

 

I'm told there are some different rear end shackles I could put on called Velvet Ride Shackles.  Or would different shocks help? 

 

If anyone has ever had this problem and/or solved it somehow, let me know.

 

Any help/suggestions would be appreciated!

 

Thanks

 

<{POST_SNAPBACK}>

 

 

GM calls this "beam shake" and it may not be unique to GM. Because on an extended cab short box truck the rear axle is moved rearward relative to a regular cab truck, the axle is not in a balanced position relative to the frame rails. There's more weight on the frame in front of the rear axle than there is rearward of the rear axle. As a result, there is a natural frequency to the frame, and it will oscillate when excited by pavement joints if the frequency that the pavement joints are encountered at is close to the natural vibration frequency of the frame.

 

One solution I've heard is that if you put a couple of bags of sand at the very rear of your bed, that will help improve the balance forward and rearward from the axle, and it will lessen the "beam shake." I've never tried this but I'd be interested if anybody else has and what the results were.

 

<{POST_SNAPBACK}>

 

 

 

I added sand bags (about 200#) to the rear a couple of times when the bed was unloaded and that pretty much solved the problem. It helps to mount a load brake rearward of the wheel wells so the bags don't slide around

[willfxp]

GM calls this "beam shake" and it may not be unique to GM.  Because on an extended cab short box truck the rear axle is moved rearward relative to a regular cab truck, the axle is not in a balanced position relative to the frame rails. 

 

Yep, I've been in F150's with the same problem. It wasn't as bad, but I have Rancho RSX9000 shocks set at 9 so I expect them harder on my ride. Definatly not a GM problem. Just the length of the truck.

[pm26]

I carry about 4 bags in the bed of my Z71. In addition to smoothing out the ride some, they are very useful in securing awkward loads, such as long pipes, ladders, boards, etc. Just place the bags on top in several places and you have a well secured load.

[redvett]

I have never had the "beam shake" but i have had Pace Edwards tonneau covers on all my GMT 800 trucks along with always getting the "LT" fully loaded might have something to do with it. Little more weight (options) & cover add some extra weight.

[bballa]

Put a shell on the truck. It will ride on the freeway like a Caddy.

[skills4lou]

Generally speaking the left lane is smoother too. ALL trucks have this issue, the bigger the truck the worse it gets. Watch an 18 wheeler's tires sometime when they are on those concrete roads. Hopping up and down like crazy.

[BigJayDogg3]

I don't remember where I saw this but there is something you can buy that you put water in and it adds weight. I wouldn't do this because it costs more than other options, but my budget isn't yours.

[bbwb]

Agree with the added weight. When I first got my truck it would bounce around and give me the feeling of warped rotors when I would come up to a stop sign. Adding a topper and additional weight got rid of the bounce during braking.

 

bbwb

[steingang2]

I emailed GM last week. They have a new body mount they are installing on my truck on tuesday. I don't yet know what the differnce could be to eliminate the beam shake. I'll find out next week if that worked. I this does not work I am thinking about putting a leveling kit on the front end to force more weight to the back end to hopefully dampen the vibration. any thoughts on that idea? A leveling kit is about $250 installed. Why have a truck bed if you have to fill it with sand bags, not to mention the hit on gas mileage.

[grampatuck]

I emailed GM last week. They have a new body mount they are installing on my truck on tuesday. I don't yet know what the differnce could be to eliminate the beam shake. I'll find out next week if that worked. I this does not work I am thinking about putting a leveling kit on the front end to force more weight to the back end to hopefully dampen the vibration. any thoughts on that idea? A leveling kit is about $250 installed. Why have a truck bed if you have to fill it with sand bags, not to mention the hit on gas mileage.

[grampatuck]

Last week the local GM service dept installed "experimental" body mounts in an effort to alleviate my problem of frame beaming. It didn't work. It might have reduced the vibration at lower speeds, but when I'm driving along at 55 and apply the binders, I can feel the vibration in my side of the seat, on the floor and in the steering wheel. My wife cannot feel it on her side. Doesn't matter the type of road or which part of town I'm in or on the highway. I'm still waiting for a copy of the service order. I'm getting my ducks lined up for a letter writing campaign. I probably won't buy another GM product. I really like my truck otherwise. Haven't had any other problems with it except for excessive outer edge wear on the tires. I believe there is an association with the beaming problem there. None of the beaming was evident until the first tire rotation at 6k mi. Then it started. There are 38k mi on it now.

 

I made an attempt to post a few minutes ago but something didn't happen just right, so it's going to appear that I don't know what I'm doing. The software isn't cooperating with me.

[grampatuck]

Concerning the frame beaming.....anyone care to join me in a letter writing campaign? I'm sending letters by snail mail to:

 

GMC

CEO Susan Docherty

P.O. Box 33172

Detroit MI 48232-5172

 

General Motors Corporation

P.O. Box 33170

Detroit MI 48232-5170

Attn: President/COO Frederick A Henderson

Chairman/CEO G Richard Wagoner Jr

Vice Chairman/Global Product Development Robert A Lutz