shaking on concrete highways

I have a 2019 Access cab that shakes pretty violently on certain types of roads, specifically concrete highways. The motion is a 2 to 3 cycles per second porpoising (rocking back and forth). The shaking is often just uncomfortable, but can be bad enough to make safety a concern. The worst I have experienced was on Interstate 80 in central Nebraska. It occurs both when the truck is "empty" and when it's towing a trailer.

It rides like butter on asphalt highways, so I'm pretty sure this isn't a tire or driveline balance issue.

My truck has stock suspension, wheels,and tires, except for larger Bilstein shocks I installed in the rear in an attempt to solve the problem. I really like my Tacoma because it is a very capable vehicle, but this is making me look at F-150s.

Any suggestions would be appreciated. Thanks in advance.

Pete

 

It is interesting that you said that it happens when you are towing also. Typically, the stock leaf springs are jittery when empty. Never a safety issue, but adding some weight in the bed (100lb) is usually enough to dampen that out.

Not sure what to make of it with the towing situation other than the particular combination might be causing it.

 

Concrete slabs can have slight variations in height and expansion causing the road to have a small bumpy or shaky feel to them, if the slabs are old w/ wear and tear it will likely be even worse. Having stiffer suspension will make that feel even more pronounced.

Suggestion, avoid all interstates and highways?

 

^^^^……that. I don’t tow anything and the truck is a daily driver, but when the bed isn’t in use, which is 80% of the time, I keep 2 50 lb bags of sand in the back right over the rear axle. Weather doesn’t matter with them since I have a roll and lock so they stay dry but it helps the ride substantially in all driving conditions.

These trucks, as most do, ride way better loaded than unloaded.

 

does it happen at all speeds?
here's my guess:
asphalt is usually a pretty homogeneous surface and the truck does not get jostled on a regular basis.
concrete frequently has things like expansion strips and grooves cut for drainage etc.
at certain speeds, the regular jostling of the truck by these "features" could match a resonant frequency of the frame/body/suspension.
When this is happening, slowing down or speeding up should change the frequency and stop the resonance, until another harmonic is reached.
Just a guess, you can confirm or disprove by changing your speed to see what happens. Or maybe you already know?

 

Sell the tacoma, buy a buick. Its a truck, of course its not going to drive like a continental over uneven surfaces.

 

Roadmaster!

 

Like butter on asphalt, like crap on concrete. Stay off the concrete. Problem solved. Your welcome .

 

Profile of the concrete road. Same thing happens on our limited concrete road surfaces we have here, particularly in one spot for several hundred feet. Even happens with some full sized trucks. My F-250 and the 20’ deck over was a nightmare. You just hit that right frequency. My Taco does it and varies with speed. It’s not the truck.

My wife’s 4Runner doesn’t feel it.

 

Same issue on I-10 Slabs of concrete in 20' sections with expansion joints.
They are "layered even" when the road has a decline or rise due to the earth is not flat.
Staircase effect of the front axle droping followed by the rear,.. again, and again.
You're rocking and if your transmission is pulling a load, (and a trailer) it will not like it.
If your empty your staircasing and feeling every inch, because its a truck suspension.

It took 5 years for the DOT to fix the issue,.... all because of the machine used to "lay" the concrete sections.
Concrete hates angles and DOT hates labor cost.

 

We have some concrete with lines cut parallel to traffic flow, it is wonky. We have other concrete that seems to be poured by drunken blind folk in 20-30 foot sections, each one has a different elevation.
Tax dollars at works folks, remember that when you think you want the big GOV involved in anything.

 

Both of my Tacomas and both of my Rams behaved the same way on concrete highway sections. Definitely not comfortable after a while.

 

The concrete slabs that make up most of I-465 around Indianapolis are horrible. They have ground most of the bad spots flat, but the pattern they used on the surface makes a harmonic hum that will bring you to your knees. I bring ear plugs just to get around the loop every time. Even my dad's
F-1lazyboy cruise-moblie makes the hum.

 

I think they pour the concrete too thin in the US... in germany they pour 8" of concrete on super thick compacted road base... then wire and dowel it...then pour another 4 " on top of that.

 

Roads do exist because of the state and federal government.

 

Sounds like par for the course for a concrete hiway. I don’t consider it a safety concern though. Concrete as a road surface has advantages and disadvantages.

 

I scrolled past all the junk responses above.

I had this very bad on my 1st gen when I had my camper on it. The frame flexes in the middle and concrete expansion joints on highways that have the same spacing cause this. Speeds between 45-60 mph were unbearable.

My 2nd gen still has this feeling occasionally, but much less pronounced and only around 55mph.

The issue is the wheelbase with our trucks in this speed range combined with the suspension not providing the right dampening/compression to handle this specific use case in the speed range.

You can either drive outside the speeds that cause this or get suspension that has adjustable compression/rebound and start playing with the settings. There may be other solutions.

 

Op.

It happened to me here in Miami where the highway was being worked on… so it looks like the concrete was poured as flat as possible but the next step of “grinding” surface to make it even was missing.

so each time I went through that stretch of road, my truck would start vibrating and kinda bouncing around… and then after months, when the works were done, I realized that they “grinded” smooth the hole stretch and my trim no longer vibrated going though..

 

Thanks for most of the responses. Smarta$$ answers are a waste of bandwidth.

I thought that it might be the resonant frequency of the suspension matching the section length of the concrete slabs. I tried varying the speed. Any speed within the legal range was problematic. It's not just interstates. Many local highways are made the same way, with the same results, so avoiding interstate highways is pointless. If there was a way to know how highways were constructed I could plan routes to avoid the problem type.

This isn't about comfort. I used to own small British sports cars so I know what coal cart suspensions feel like. I have owned other pickups so I know what rear end "jitter" is. My son and his family joined us on our last trip, towing a similar trailer with a Ram 1500. He could tell the worst roads were rough, but weren't a problem.

This is a safety issue. When the truck is dancing hard enough to blur my vision...

 

Correct, well aware of history,,,, As do privately funded, on budget, on time, well surfaced roads. Just because they built it, doesn’t mean they build and rebuild properly.