I'll add my experience with wash board roads.
Driving heavily washboarded roads is an art in itself. For me, being an old jeeper/off-roader, deflating down the tires helps the most. I settled on 28 lbs, front and 30 lbs. rear as optimal for washboard with the camper on. (IMHO, this is not a death defying act) The sidewalls now take the heat, so the speak. I would only deflate if I have very good tires, which is the case. And obviously, only if you have a BIG source of air and/or CO2 to get said tires back up at pavement. Another important help on washboard are well tuned shocks**(see below for death defying).
On that Death Valley road spoken of above, Rick and I started in to Saline Valley from the south with full pressure. The road gradually became worse and worse, with occasional then fully wash board surface crossing-washing those 10 mile across alluvial fans. Our plan was to motor on with full pressure until we couldn't take it any more. After a few hours and a gradual slowing to 5 mph, we finally had had it. Dropped the press down and that perpetual grimace and clenching of teeth finally relaxed, we were whizzing along at 15 mph, sidewalls a-flexin'. Every time we stopped we checked the heat of the tires. Slightly elevated temperature here, not enough to abort the mission. If they got real hot, we'd surely have gone to plan 'P'. Pressure back up.
It's rare to drive on complete washboard. It usually comes in waves with a patch here and a long section there, but not contiguous. Trying to find the current optimum sweet spot on the road, I find myself on the wrong side of the road most of the time, with the left tires on the smoothest part at the very edge of the road. I drive every foot of the road, sweeping right or left if there is some better surface to be had (like a PT boat trying to dodge floating mines or torpedos) working the surface. Something about the shape of the washboard coming the other way, and left hand drive makes it easy to be very precise, way to the left. Very occasionally, the right side of the road, way to the right is better. Almost never down the center where everyone else drives, as that's where the worst washboard resides.
**It sounds like i've thought about this, right? With good reason.
read on:
"Shocks? We doan' need no steenkeeng shocks!"
Near Telluride CO, 1992, driving my '90 Jeep XJ to meet some narrow gage railroad geeks and walk/talk the old grades. It was 10pm on a county gravel road from Ophir to Vance Jct. I was alone and very tired, having driven 18 hrs. to get there, and was going about 20 mph downhill and was about 2 miles from the campsite. The road was cut into the hillside and followed the contour of the land. Good gravel surface until,...... (up jump da debil)
there was a short but intense section of washboard (what I call BIG washboard) leading to a hairpin curve to the right. I have driven this road a handful of times before but don't remember any washboard at all. I think it depends on the schedule of the county road grader.
Meanwhile, at less than 20 mph now, the rear axle (leaf sprung) started to hop....wildly, I mean 'Perfect Storm' pump-up-and-down wildly, and the rear of the jeep started to drift left toward the cliff. (I knew I should have replaced those no-good rear shocks before driving from CA to CO, but was too cheap)
I was in an abrupt r. turn, now brakes full on (which made it worse) and compensated turning into the drift when.....
.. the front end dropped
.............................right
.................................over
.................................the cliff.
The first roll was an endo. The rear came over my head and crashed into a 6" trunk Aspen, grenading the fiberglass rear hatch. I was now just for a second, upside down and sideways on a 70 percent slope of rock, outcroppings, dirt, and some small trees when the barrel rolls started. The 2nd, 3rd, 4th and 5th roll were all sideways in a crescendo and accelerando to the end. I knew how many rolls there were because of my weight hanging on the seatbelt at the apex of each roll each coming faster and faster.
125 feet down beyond the road's edge I finally stopped on a narrow ledge, laying on the drivers' side. Of the 12 windows in the jeep, only the drivers door and wind wing were intact and I was dangling on them. I got the belt off and caveman crouched my way back through the jeep (on its side) through the non-existent rear hatch. My priceless 1921 Conn Bass trombone was in a leather case, catapulted out the window and was flattened by the jeep rolling over it.
My neck hurt (cracked 4th vertebra) probably from banging on the sunroof glass, but I knew I was going to live. I tweezed bits of sunroof glass out of my scalp for months.
The trombone was not so lucky.
I crawled up the slope in the dark (actually I had the sense to get my head lamp on) and walked a couple miles to the nearest house near Ilium, CO. I knocked on the door and the folks called 911. Eventually an ambulance carried me to Telluride after-hours clinic and the DR. checked me out. He was going home then, so I checked into a hotel for the night.
I rented a JEEP the next day (the rental co. had to spend time telling me how to use it. Ironic.) to go over and survey the crash site. I called my insurance provider and they sent a big tow truck over to retrieve the errant jeep. Stuff was strewn all over the hillside. The tow operator tried unsuccessfully to pull the XJ up the steep slope. He called for backup and a 5 ton tow came along. Between them, with 'D' rings, snatch blocks, chokers, extra wire rope they eventually see-sawed the rig up to the road. The retrieval/towing bill was $1000. My XJ was a total. There was not one square foot of sheet metal that was not mangled. The unibody/frame held up great.
I guess the moral of the story is:
Have good shocks on your rig
Don't assume the road surface will be as you remember it.
Maybe 4WD is a good idea on washboard.
Don't drive when tired.
regards, as always, jefe
* This post was
edited 07/04/08 12:14am by jefe 4x4 *
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That's quite some story jefe ... glad you made it through that in as good a shape as you did.
Actually, this does bring to mind that you can encounter something worse than a straight, flat washboarded road, and that's by throwing in curves or worse yet, a curve with an upslope or particularly a downslope section at the same time. Sometimes you're already dancing along the surface of a washboard road with the rear end "floating" around a bit as it is. But I have several times carried a bit too much speed into a washboarded corner, and had to pull off that delicate balancing act of reducing speed without totally losing it (all while the rear axle is happily bouncing into oblivion with associated rear tire traction approaching zero, and the rear end wanting so much to become better acquainted with the front end). A couple of times though, adding in a slope at the same time unacceptably increases the the already elevated pucker factor. My wife has probably not been too enamored of yours truly going WHOA, WHOA, WHOA! during these times (while I am quietly uttering to myself in another corner of my mind, "I think I am going to lose it").
These episodes were luckily in smaller 4x4 vehicles (with no cliff edge as jefe had to unfortunately deal with), but in any regard, I hope to never repeat same with my full-sized truck & camper.
I learned to drive on washboard in the Sahara desert. I spent six years and thousands and thousands of miles on washboard. As the washboard developed in the sand, vehicles would go over to the edge to avoid it and eventually the road (and washboard) was up to two miles wide. Then people would start to get lost... This was in the days before GPS. You have to drive faster than seems sane on washboard. There were times when I drove up to 70 mph on washboard. Of course this was not in a loaded TC (oplus I was in my twenties) In any event the basics to driving on washboard are:
1) You must drive fast(between 30 and 40 mph) - the idea is to skip across the crests of the washboard. Of course you can not do this on narrow, steep or winding roads.
2) Use the entire road - left to right
3. Lower air pressure within reason. I.E. from 80 down to 60 on a fully loaded TC.
I recently drove the "Hole in the Rock" road in Utah and I found the sweet spot to be about 30 mph with my fully loaded rig. This was also the sweet spot in the Big Bend NP and SP. 10 mph would shake the rig apart.
Then there was the Hart Antelope Reserve.....
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Quote: ...vehicles would go over to the edge to avoid it and eventually the road (and washboard) was up to two miles wide. Then people would start to get lost... This was in the days before GPS.
This is sounding interesting! Sounds like a possibility for an article (reminiscing about your days in the Sahara, and experiences sand driving). I'll bet lots could learn from reading your experiences accumulated over many years there!
I have a close friend that mapped the perimeter of the largest trans-national park in Namibia/South Africa, traveling with the Kalahari bushmen as guides (using several land cruisers).
I'm driven a lot of washboard in desert and was always amazed how quickly road conditions would change, even in the same area, from week to week. Like others have pointed out, I have also found certain washboards where 70 MPH seemed to be the only speed where everything smoothed out - but could end disastrously when you came to that first 3' drop!
Washboards are created by naturally ocuring resonant frequencies of aeolian or alluvial deposition of desert sands - combine with resonant frequencies of suspension systems on off-road vehicles and you have opportunity for resonant waves contributing to each other (really big bumps, even getting airborne) or canceling each other (road gets magically smooth, as long as speed and road condition stays constant.) Washboards can also be created from the resonant action of vehicle suspension systems as well.
I remember a Ford F-150 commercial years ago where the truck was driving across a long line of railroad ties. Despite close-up shots of the front wheel violently jerking up and down, the occupants of the truck cab were shown sitting quite comfortably. I also recall it came out later that the ties were preciously laid out so at to match the natural spring resonance of the vehicle, speed was tightly controlled, and the shock absorbers were actually removed from the truck so as not to interfere or dampen the natural response, which would have imparted some more of that movement into the truck body and created a much less tolerable ride.
To try and set up a "cancellation" resonance previous suggestions (vary speed, and/or tire pressure) all help. One other item I have found to be very helpful (if you have the ability) is to vary the stiffness of the shock absorbers, assuming you have in-cab air adjustable shocks. While you generally want much stiffer shocks off-road than you do on-road, sometimes a softer shock will let the unsprung mass "absorb" a lot of the resonance abuse and keep it from transferring into the frame and body.
WOW jefe! I have had some close encounters during my 27 years of off-roading but nothing as bad as that. I have always managed to keep it rubber side down. Glad you are still with us to tell the tale.
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JeffPritchard wrote: CO2 in the tires? ??? Air pressure is air pressure.
CO2 liquefies under pressure, so a lot of gas can fit in a little bottle. Some OHV people carry the CO2 cylinders instead of a compressor. The extraction speed is only limited by cylinder freeze up, and is much faster than portable compressors. When you have 4 or more big tires, filling with a compressor takes a long time.
Ok, I guess I missed the point. Was he trying to say that they kept the tire pressure low while going over the washboard road, and then incidentally they used co2 to air back up afterwards?
jp
* This post was
edited 07/03/08 11:59pm by an administrator/moderator *
JeffPritchard wrote: CO2 in the tires? ??? Air pressure is air pressure.
CO2 liquefies under pressure, so a lot of gas can fit in a little bottle. Some OHV people carry the CO2 cylinders instead of a compressor. The extraction speed is only limited by cylinder freeze up, and is much faster than portable compressors. When you have 4 or more big tires, filling with a compressor takes a long time.
Ok, I guess I missed the point. Was he trying to say that they kept the tire pressure low while going over the washboard road, and then incidentally they used co2 to air back up afterwards?
jp
You got it now.
* This post was
edited 07/03/08 11:59pm by an administrator/moderator *
I don't recall hearing your washboard road jeep accident at the campfire in DV. You mighta scared me into staying on asphalt! Glad you are here to share your experience.
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