Truck bouncing down Hwy 101

[DieselDixon]

Okay, I don't know what the technical name is for this, pogo sticking or what have you? But I was heading back from Los Angles back up hwy 101 on Saturday just north of the 405 and on stretches of 101 where there is a concrete pavement my truck, a 03' 2500HD CC LB starts bouncing valiantly, I was totally unloaded too. It has done this before on other hwys but not this bad and for this long so I need to find a way to fix this! So what is the fix my technical friends, new shocks or what?

[mdadgar]

Isn't it awful? Mine does it, too. It only happens on concrete freeways. Asphalt is fine.

My Kelderman rear air suspension helped, but not enough.

I'm gonna try Bilsteins next. The rear shocks are WAY under-damped, which is what causes the oscillations.

- Mark

[Lone Eagle]

We have a few sections of concrete on I-15 in southern Utah that are so bad that everyone runs in the fast lane. Even the Highway Patrol cars run it and they have some heavy duty suspensions. If you find something that works, be sure to let us know. Later! Frank

[FirstDiesel]

One word

Bilsteins

I changed the stock shocks at 7500 miles because of that effect on a bridge we have here on the interstate. Is it as smooth as a caddy??? No But it is sure as smooth as I would expect from a 3500 dually. No one is losing their lunch in the backseat any more.

[Brandenburg]

It is caused by the expansion joints in the concrete setting up a harmonic vibration in the vehicle suspension. I heard from my Grandpa who was a GM engineer that there were some brand new concrete roads in the sixties that could shake a new car apart. :eek: They determined that if the distance between each joint was varied and not kept the same, this would not happen.

[FirstDiesel]

Yea, tell that to the engineers and the contruction team that bulit I526 in Charleston, S.C. The road is less than 10 years old and the had to replace all the expansion strips on one of the bridges. "Defective Design" Guess what?? They knew it was defective design when they used them!! And the surface of the roadway is so bad that there are trucks that are having major failures on a weekly basis from driving this road. The answer from the HWY Department. Yes we know the road is bad but the work the contractor did met the spec of the bid!! HUH??? So they wrote bad specs, the builder did bad work and my tax dollars bad for a bad road.

Gotta love it!!!

[DieselDixon]

It doesn't seem to be concrete roads in general though, the one's I have been on that did this were roads that had been resurfaced. I think they actually grind a layer off the top? Anyway, if you are sure about the Bilsteins I will put them on!

[dickheller]

I just got back from a trip to Alaska and I had severe pogo stick effect in my ride on concrete roads. I installed Bilstein on my truck last week and what a differance in the ride and handeling with or withought my 11,000 lb trailer. :D :D :D

[WhiteDiesel]

I left Pismo Beach today heading South on the 101 and noticed the exact same thing. After riding dirtbikes in the sand dunes since Thursday, it actually felt good on the back! Trucks have stiffer rear suspension. I had a lowered 96 Silverado with airbags, and it did the same thing.

I put 2 100 pound steel plates (two huundred all together) behind each rear wheel well and it fixed the bounce. Another trick/solution coming from the lowered truck world are Velvet Shackles. www.drivetrain.com (http://www.drivetrain.com/velvetride.html)

[Sandaholic]

My truck does the pogo stick trick too, I put the bilstein on and did not fix that problem. The bilstein do help in other ride area, but not with the freeway hop. I too notice it on some concrete freeways like the 101, sections of the 405 and 118. My old truck '98 Ram did the same exact thing on the freeways. One any significant weight is add, it smooth the ride out. From what I heard was the cause of the problem was the stiff rear suspension not flexing enough while unloaded, kinda like no suspension at all in the rear.

[David Proske]

We have a section of highway out here on 59N that will send you to the chiropractor in a unloaded truck. A few years ago i even saw a car bottem out. Even with my stock shocks its a lot better once I put my tool chest and Leer top on which put a little load on the rear end.

[sonofagun]

The problem is that the heavy semis float over the expansion joints and land in the middle of the next patch of concrete causing the ripples that tranlate into our rock and roll ride Sort of like lifting your weight when you turn in snow skiing - moguls are created the same way.). Some freeways out west have new expansion joint stabilizers that take it all out but that's limited to newly poured roadway.

There aren't any good fixes. Velvet rides help a bit, better shocks help a bit, loading the bed helps the most but it takes at least 1000# to make any real difference, and it's still rough.

I spend my time in the fast lane when the roads are that bad. It ticks off the race car drivers but their cars ride much smoother than my HD truck. My kidneys appreciate it!

Bob

[Rockin]

I would like to take a leaf or so out and add an adjustable air bag to improve versatility. My truck (will) be used for both driving on snowy roads to ski areas (often have ice washboard), washboard dirt roads etc and pulling a goose neck horse trailer.

It would be nice if I could make both work. I think shocks will help but with a little less spring, the bed won't need as much load for driving empty.

Anyone ever do anything like this?

[HD-Nate]

Originally posted by son of a gun:

There aren't any good fixes. Velvet rides help a bit, better shocks help a bit, loading the bed helps the most but it takes at least 1000# to make any real difference, and it's still rough.

Bob I AGREE

Every truck I have owned has done this on one road or another. Short bed, long bed, extended cab, standard cab, etc. There is a stretch of road here in KC that every truck I have driven has done this. Yes even F*rds and D*dges. The shorter the truck the worst the rocking horse effect is.

My crew cab has handled it the best so far but you can still feel the rocking.

It always seems the worst on some concrete roads. I cant ever remember the problem on asphalt.

[DMAX Daddy]

Bilsteins do not help. I live along this section of the 101 and the only solution I have found so far is about 1000 pounds in the bed.

Im going to try Velvet Ride Shackles if they ever become available for an '03, but that probably wont help either. :(

[DieselDixon]

Dmax Daddy,

Well that is good to know, but I am sure there are other reasons to install the Bilsteins.

If you even get the velvet rides on let me know if it worked. You got a perfect test road for them that's for sure.

[JEBar]

Rockin ..... In an effort to improve the ride of my truck, I had the targest removable leaf on each side on the rear taken out from under my 3500 and added Air Lift Air Bags w/ onboard compressor. Had this done about 30,000 miles back and have been extremely well pleased with results. I have found that adjusting the pressure in the air bags can really help (note I did not say completely eliminate) with the concrete interstate hop being discussed in this thread. Based upon the truck's ride since this conversion, if I bought a new one today, this would be one of my first upgrades ... Jim

[DMAX Daddy]

Diesel Dixon,

Bilsteins are worth EVERY cent. My only regret when I put them on at 800 miles was I hadn't doen it sooner!

[DetroitBob]

DieselDixon, I have a 2002 EC 3500 GMC D/A. I needed to drop the rear to accomadate my 5th wheel so I installed the Velvet Ride shackies. Did not help at all. The ride did not improve either loaded or empty. IH 5 north of Seattle, IH 20 east of Dallas and IH10 west of Lafayette,LA , IH 40 east of Albuquerque caused me the same bounce you described. Some places the only releif was to drive in the left lane when you could.

Good luck.

BoB