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9/22/2017 12:11:25 AM
Posted: 4/12/2002 11:52:16 AM EDT
About 15 miles of dirt road to my best shooting spot is inflicted with the ‘washboard’ pattern. It seems like the only way to avoid rattling my brains out is to go 5 mph or 45 mph. At 5, it takes me forever to get to my destination. At 45, I get the impression that I’m battering my tires and shocks to death and risking a sure-fire trajectory into the canal that borders the road. It’s getting to the point that I don’t want to go out there anymore. The road used to be graded by the county every year, but they’ve slacked off. Any suggestions for handling these kind of roads? [:(]
Link Posted: 4/12/2002 11:59:43 AM EDT
Adjust your vehicle's tire pressure until you find the highest possible resonance frequency for your vehicle's suspension. You know, the speed that matches the washboard. You can tell when the speedo is readable and not blurred or double. Or, take the wife's car. Planerench out.
Link Posted: 4/12/2002 12:01:02 PM EDT
Link Posted: 4/12/2002 12:01:39 PM EDT
You've got to live with it. You've got little standing (not living on the road) to ask the county to grade it or pave itand there is nothing you can do to smooth it out unless you have a grader handy. Maybe get yourself a crappy truck and only drive that to the range, so when you blow through a set of shocks every year it'll just be the truck, not the car you depend on.
Link Posted: 4/12/2002 12:57:12 PM EDT
Looks like balloon tires or lowered air pressure may be a key. While driving Alaska's graveled highways, countless people have no doubt wondered how an unpaved road surface turns into a bouncing bed of corduroy. Keith Mather, former director of the Geophysical Institute and UAF vice chancellor for research, wondered the same thing, and in 1963 he published a paper on a subject near and dear to many Alaskans' shock absorbers--the formation of washboard roads. Mather, who was studying nuclear physics in Australia in the early 1960s, wasn't satisfied with the theories of the time: that washboard roads were caused by "peculiar" soil, wind from passing vehicles, car exhaust, or impulses from car engines. He doubted all these possible causes because he noticed that many different surfaces, such as train tracks and ski trails, also can be afflicted with tiny roller coaster patterns. Mather set up an inexpensive experiment at his lab in Melbourne. He assembled a contraption in which a tire connected to a central arm moved in a circle like the second hand moves on a clock. He covered the floor with sand and sent the wheel, which was about the size of a lawnmower roller, circling around the track. He described the homespun project in his article: "We moved the wheel around the track by putting a finger behind the shaft and pushing it around the (track) to the beat of the family metronome. Greatly to my surprise this produced fairly regular little corrugations several inches apart in the sand." Mather found that washboard roads developed not only in sand, but also on "roads" of rice grains, sugar, and split peas. The key, he found, was that the surface was dry, as Alaska roads often are in the spring. The faster he spun the wheel, the faster washboard appeared. With repeated passes of the wheel, he watched the road ripples multiply like snowshoe hares. He noticed several keys to the formation of washboard roads: the road surface had to be non-rigid; the road had to be dry; and washboard tends to form just beyond an irregularity in the road surface, such as a bump, dip or small rock. Bumps in the road surface cause the tire to hop in the air. When the tire crashes down, it forms valleys by spraying sand and gravel forward and sideways. The moving tire ramps out of the valley and hops again. Thus, the washboarding process repeats itself. The washboard design spreads across the road when other cars repeat the action of the car that initiated it. Mather pointed out that bumps cause cars to react in the same way even though vehicles come in different weights and sizes, and with various suspension systems. He concluded, sadly, that other than slowing to about 5 miles per hour or using balloon tires to cushion the road, there isn't much drivers can do to prevent washboard roads from forming. Mather, who is now 74, retired, and living in Eugene, Oregon, said he still has heard of no solution. At least for the time being, it looks like corrugated road surfaces will remain a literal pain in the neck, particularly in many developing countries, where major highways feature hundreds of miles of milkshake motorways. Mather did note that some people, particularly Alaskans, view washboard roads with a certain amount of affection, however. He wrote that the bumpy stretches often are seen as "a welcome assurance of privacy in the outer reaches of suburbia." .
Link Posted: 4/12/2002 2:35:43 PM EDT
Do like the desert racers do when modifying their pre-runners (if you've got a truck): bigger tires, lower pressure than used on pavement (but enough to prevent flats and losing the bead unless you use bead-locks), the best shocks you can afford plus modifying suspension to increase wheel travel (not just a simple lift). Stock suspension sucks, as you've discovered. More travel lets you drive faster and in more control. [:D] If you're in the family sedan or a motor home, well, probably you're limited to just lowering tire pressure and using the best shocks you can. [:(]
Link Posted: 4/12/2002 3:24:57 PM EDT
Thanks, guys. I kinda figured I was SOL. I'll lower the air pressure a little when I go out this weekend. Max for my 31s is 50psi; I guess I'll try 45 to start. Interesting stuff, nightstalker. Thanks.
Link Posted: 4/12/2002 3:35:49 PM EDT
[Last Edit: 4/12/2002 3:37:44 PM EDT by liberty86]
Originally Posted By nightstalker: Looks like balloon tires or lowered air pressure may be a key. While driving Alaska's graveled highways, countless people have no doubt wondered how an unpaved road surface turns into a bouncing bed of corduroy. Keith Mather, former director of the Geophysical Institute and UAF vice chancellor for research, wondered the same thing, and in 1963 he published a paper on a subject near and dear to many Alaskans' shock absorbers--the formation of washboard roads........
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Only on ar15.com...(Edited to add, Ya gotta love this place..)
Link Posted: 4/12/2002 5:25:12 PM EDT
45 lbs. ?? Try about 25. With 45-50 you should feel every pebble in the road....
Link Posted: 4/12/2002 5:32:49 PM EDT
Originally Posted By Striker: Anytime I have to rattle my fillings out on one I usually manage to find a spot on the road that is relatively smooth compared to the rest. Even if it means driving on the shoulder of the road. I take the slow method so I don't pound my drive train to pieces.
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I agree with this tactic. I do this all the time. The problem around here comes from the fact that when the roads get really dry they tend to washboard. The only way to fix the problem is to grade the road, but this is useless unless the roads have been rained on recently. We have been without significant precipitation now since October. You can imagine our washboards.
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