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  • washboard roads

    My brother Robert is visiting Phoenix. While his wife Iris attended a line-dancing convention in Mesa, Robert and I drove the Apache Trail to Roosevelt Lake in his rented Nissan Rogue. This road was built in 1906 and has sections which have not been widened or improved.

    At one view point we encountered a biker who graduated from Ballard High School in 1959. That's the same year I graduated from his school's neighboring rival, Queen Anne High School in Seattle. It made me think: this guy is riding a Harley – why aren't I?



    The road has a lot of washboarding. Robert (wearing the blue cap in the above photo) asked me if I knew what caused it. I mentioned something about it being due to all vehicle suspensions being sprung to provide the same natural frequency. But my understanding of why this causes washboard roads is vague, at best.

    Do you have an explanation for this phenomenon?

    Allan Ostling

    Phoenix, Arizona

  • #2
    That's the way the "roads" look on my family's cattle ranch right after we grade them with a bulldozer after the spring runoff is done.

    The 'dozer's track treads leave that rippled/washboard pattern behind.
    Steve
    NRA Life Member

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    • #3
      The traction of the tires pushing on the dirt does the same thing as the friction of the wind on water...causes ripples.
      Any products mentioned in my posts have been endorsed by their manufacturer.

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      • #4
        There's allot of that where im from, there's a multitude of reasons and much of it is suspension and some of it is what Winchman stated as Iv noticed a pattern that it is generally worse on the climbing side of the roads where I live in the mountains...

        Suspension coupled with a car trying retain traction I think is the biggest culprit... braking downhill can be bad to but at least its all four wheels involved unlike most cars climbing...

        believe it or not the best car iv ever driven on washboard was a yugo...

        I think because everything was so flexy it really didn't get into the common frequency range of other well designed vehicles --- I could do 70 over washboard and be drinking a cup of coffee...

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        • #5
          I've been running graders off and on for about 30 years. It's from overuse and excessive brakeing by incompetent drivers.

          Actual removal of that washboard so it doesn't come back right away is due to not enough time spent by those grader operators to cut below the washboard and respread the road surface back in place.

          Pete

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          • #6
            Originally posted by A.K. Boomer
            --- I could do 70 over washboard and be drinking a cup of coffee...

            I learned to drive in a Ford Customline in an area where all the roads were gravel and mostly washboarded (we called it corrugated).

            A moderately heavy car with fairly narrow tires can be driven quite fast but to get there requires accelerating through a speed zone that would shake your back teeth out. If I recall correctly that was about 40mph. Once above that speed the ride was dead smooth but traction was very tenuous and steering required a very gentle touch.

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            • #7
              Originally posted by uncle pete
              I've been running graders off and on for about 30 years. It's from overuse and excessive brakeing by incompetent drivers.

              Actual removal of that washboard so it doesn't come back right away is due to not enough time spent by those grader operators to cut below the washboard and respread the road surface back in place.

              Pete
              Hi,

              I used to run a crusher and do a little blade work in my younger days for my late ex-Father-in-law. I agree, to much traffic and too fast of speeds will cause washboarding.

              At the very root of the problem is often the gravel itself. Too much sand and not enough crushed rock and then clay to bind it all together properly will allow washboards to easily form. It ain't easy to make proper class 5

              dalee
              If you think you understand what is going on, you haven't been paying attention.

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              • #8
                Originally posted by uncle pete
                I've been running graders off and on for about 30 years. It's from overuse and excessive braking by incompetent drivers.
                In the African deserts you can drive for a hundred miles without touching the brakes but the corrugations are just as bad as anywhere else. Nothing to do with "incompetent" drivers.
                "Patriotism is the last refuge of a scoundrel"

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                • #9
                  Originally posted by The Artful Bodger
                  A moderately heavy car with fairly narrow tires can be driven quite fast but to get there requires accelerating through a speed zone that would shake your back teeth out. If I recall correctly that was about 40mph. Once above that speed the ride was dead smooth but traction was very tenuous and steering required a very gentle touch.
                  I cracked a widshield once at speed on a corrugated gravel road and as soon as I dropped to below 40 mph that darned shaking just dropped the windshield in my lap in pieces.
                  "Patriotism is the last refuge of a scoundrel"

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                  • #10
                    http://www.google.com/#hl=en&sclient...=1329&bih=1036

                    David Merrill

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                    • #11
                      I'm 66 and still have my Harley but haven't been on it for a couple years owing to my hip problem. Hopefully I'll have my knees in the breeze soon. Here's a scientific explanation of roller-induced rippling:

                      http://www.autoblog.com/2009/07/09/w...s-the-science/

                      In the 60's and 70's I used to spend quite a lot of time in the SoCal Mojave desert on dirt bikes and have zillions of miles driving my bikes and trucks on those roads and there is a sweet spot speed you can find to make the ride almost smooth but as has been mentioned you have to get through a total vehicle resonance speed first. What is miserable is if you are in a caravan of vehicles and the lead driver doesn't know enough to get to the sweet spot and you can drive for miles in the chatter zone. Passing in the dust is extremely dangerous as you can't see what is coming the other way so you have to ride it out.

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                      • #12
                        I don't know that it qualifies as washboarding, but back in the early '60 I observed the asphalt pavement being formed into ripples, or more accurately waves, at a traffic light on Dort Hwy at Lippincott, where the trucks hauling Buick bodies from Fisher 1 on the south side of Flint to the Buick assembly plant downtown, would come to a juddering halt for a red light. I suppose there were other trucks that contributed, but these were most numerous. It always happened in hot weather, and the suface of the asphalt was smooth but wavy. the worst case was nearly a foot in height from trough to crest. Two or three humps in 8-10 feet. Great fun to ride my bicycle over when there was no traffic. The City would come and repair it periodically, but it never lasted.
                        Weston Bye - Author, The Mechatronist column, Digital Machinist magazine
                        ~Practitioner of the Electromechanical Arts~

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                        • #13
                          Wow, sounds like a job for cement...

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                          • #14
                            Originally posted by Weston Bye
                            I don't know that it qualifies as washboarding, but back in the early '60 I observed the asphalt pavement being formed into ripples, or more accurately waves, at a traffic light on Dort Hwy at Lippincott, where the trucks hauling Buick bodies from Fisher 1 on the south side of Flint to the Buick assembly plant downtown, would come to a juddering halt for a red light. I suppose there were other trucks that contributed, but these were most numerous. It always happened in hot weather, and the suface of the asphalt was smooth but wavy. the worst case was nearly a foot in height from trough to crest. Two or three humps in 8-10 feet. Great fun to ride my bicycle over when there was no traffic. The City would come and repair it periodically, but it never lasted.
                            That has a very technical term "Pushing" as in the asphalt being pushed. It happens worst where the pavement surface has been built up over the years (overlaid) with thin layers of aspalt (and therefore with fine aggregate) which doesn't have the stability of a properly constructed asphalt pavement where only the thinnest top layer will have the finer aggregate.
                            "Patriotism is the last refuge of a scoundrel"

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                            • #15
                              Originally posted by A.K. Boomer
                              Wow, sounds like a job for cement...
                              I assume you mean concrete. Cement is just the "glue" that holds it together.

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