washboard roads

[aostling]

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?

[RetiredFAE]

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.

[winchman]

The traction of the tires pushing on the dirt does the same thing as the friction of the wind on water...causes ripples.

[A.K. Boomer]

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...

[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

[The Artful Bodger]

--- 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.

[dalee100]

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

[jep24601]

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.

[jep24601]

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.

[demerrill]

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

David Merrill