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BajaDove
Nomad
Posts: 194
Registered: 11-23-2008
Location: La Paz
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If you're going to go fast stop every ten minutes take a wrench and screwdriver to every nut and bolt, easier than looking for them when the car
falls apart.
If its not where it is, its where it isn\'t.
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mrbotete
Newbie
Posts: 11
Registered: 5-2-2011
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If you're going to go fast stop every ten minutes take a wrench and screwdriver to every nut and bolt, easier than looking for them when the car falls
apart.
It seems to me that stoping every ten minutes it would defeat the purpose of going fast or slow....timewise
But I get your point...this roads can really destroy your car nut by nut
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wessongroup
Platinum Nomad
Posts: 21152
Registered: 8-9-2009
Location: Mission Viejo
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Mood: Suicide Hot line ... please hold
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Thanks to all.. good information... it all helps...
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mtgoat666
Select Nomad
Posts: 18376
Registered: 9-16-2006
Location: San Diego
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Mood: Hot n spicy
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inquiring minds want to know???????
more interesting questions::::::
what wheel movement or driving style causes washboards?
do fast or slow drivers cause the washboards?
do particular vehicles cause more or less washboard formation?
should the responsible vehicles be cited/fined to pay for more frequent grading to maintain road?
are particular road beds better or worse at forming washboards?
why don't road contractors use better materials in road beds to prevent formation of washboards?
it seems to me that many road projects bring in crushing plants to prepare aggregate for road base, so why don't engineers specify better/best
aggragate for use in road bed?
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wessongroup
Platinum Nomad
Posts: 21152
Registered: 8-9-2009
Location: Mission Viejo
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Mood: Suicide Hot line ... please hold
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According to Tom Pettigrew, a Forest Service engineer, the cause is an unlikely source: your car's suspension. (Well, maybe not yours specifically,
but it's not innocent in this matter, either.) A vehicle's suspension system distributes the shock and energy of road irregularities with a bouncing
rhythm called harmonic oscillation. At each downstroke, the wheels exert extra force on the road, causing the particles in the road to either pack or
displace at regular intervals. Once a pattern of ruts starts to establish itself, it becomes self-reinforcing due to what engineers call forced
oscillation. The next car hits the same irregularities in the road and bounces at the same rate, causing the pattern to become more and more defined.
Forced oscillation overcomes minor variations in oscillation rate that might otherwise arise due to differences in car weight.
Wouldn't variations in speed affect the washboard pattern? Sure, which brings us to another critical part of the feedback loop: you, the driver. Drive
too fast on a washboard road and the downstroke exerted by the car wheels may meet the road at a point where a bump is ramping upwards. You know what
that means: You bounce off the ceiling. Instinctively most drivers slow to a speed at which the downstrokes coincide with the troughs between bumps,
reinforcing the pattern.
Washboarding is inevitable in any unpaved road that sees fairly heavy traffic. The only way to avoid it is to: (a) radically redesign how automotive
suspensions are made, (b) give up suspensions altogether, or (c) keep off those dirt roads.
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bajalou
Ultra Nomad
Posts: 4459
Registered: 3-11-2004
Location: South of the broder
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I drove to Valle Trinidad from Highway 1 a couple weeks ago. There was a portion that had been graveled and it had terrible washboard. Then the
gravel ended and the roadway was smooth dirt. - No more washboard on the dirt portion.
No Bad Days
\"Never argue with an idiot. People watching may not be able to tell the difference\"
\"The trouble with doing nothing is - how do I know when I\'m done?\"
Nomad Baja Interactive map
And in the San Felipe area - check out Valle Chico area |
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1bobo
Nomad
Posts: 116
Registered: 2-5-2010
Location: Mulege
Member Is Offline
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| Quote: | Originally posted by wessongroup
According to Tom Pettigrew, a Forest Service engineer, the cause is an unlikely source: your car's suspension. (Well, maybe not yours specifically,
but it's not innocent in this matter, either.) A vehicle's suspension system distributes the shock and energy of road irregularities with a bouncing
rhythm called harmonic oscillation. At each downstroke, the wheels exert extra force on the road, causing the particles in the road to either pack or
displace at regular intervals. Once a pattern of ruts starts to establish itself, it becomes self-reinforcing due to what engineers call forced
oscillation. The next car hits the same irregularities in the road and bounces at the same rate, causing the pattern to become more and more defined.
Forced oscillation overcomes minor variations in oscillation rate that might otherwise arise due to differences in car weight.
Wouldn't variations in speed affect the washboard pattern? Sure, which brings us to another critical part of the feedback loop: you, the driver. Drive
too fast on a washboard road and the downstroke exerted by the car wheels may meet the road at a point where a bump is ramping upwards. You know what
that means: You bounce off the ceiling. Instinctively most drivers slow to a speed at which the downstrokes coincide with the troughs between bumps,
reinforcing the pattern.
Washboarding is inevitable in any unpaved road that sees fairly heavy traffic. The only way to avoid it is to: (a) radically redesign how automotive
suspensions are made, (b) give up suspensions altogether, or (c) keep off those dirt roads. |
Ran out to Punto Chivato the other day (freshly graded, BTW) and got to thinking about the physics of washboard formation. Thanks, now I have an
answer!
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shari
Select Nomad
Posts: 13048
Registered: 3-10-2006
Location: bahia asuncion, baja sur
Member Is Offline
Mood: there is no reality except the one contained within us "Herman Hesse"
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I'm surprised nobody mentioned the following point....
All washboard roads are different and have different heights and widths of the troughs between the bumps and THIS is what you have to judge in order
to regulate your speed. For example..normal smaller washboard with close "valleys" is generally better to go faster as it smooths out the ride...but
you dont need to go super fast in which case you may lose control easily and skate around if your tires have too much air pressure.
In the good old days when it was washboard all the way here from Vizcaino, the section from rebombeo to the turnoff was awful big big topes like
washboard and you could not use the go fast method or you would do mortal damage to your vehicle....as it is washboard loosend nuts and screws,
dashboards, tire lug nuts, hoses and a myriad of other goodies.
so one can not really say that you can use the go fast rule on all washboard...man oh man, am I glad we dont have to deal with THAT any more except
when we go visit baja blanca! or Russ!
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BajaBlanca
Select Nomad
Posts: 13196
Registered: 10-28-2008
Location: La Bocana, BCS
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not THAT is funny !!!!!
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Baja12valve
Nomad
Posts: 185
Registered: 7-12-2006
Location: Oak View
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Soft suspension is also key. I have in cab adjustable shocks. I soften them to the max and it makes all the difference in the world. Stiff suspension
is a real bummer, I have had them before and I will never have one again.
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mcfez
Elite Nomad
Posts: 8678
Registered: 12-2-2009
Location: aka BN yankeeirishman
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I fly it .....slow speed such as 10-20 mph is too jittery.......always knocking my false teeth right onto the floor  I will lower tire pressure a bit before doing the fly.
Old people are like the old cars, made of some tough stuff. May show a little rust, but good as gold on the inside.
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motoged
Elite Nomad
Posts: 6481
Registered: 7-31-2006
Location: Kamloops, BC
Member Is Offline
Mood: Gettin' Better
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| Quote: | Originally posted by BajaGringo
We have 15+ miles of mostly washboard between us and town. The best compromise for body, vehicle and safety is 4-20-40.
4 wheel drive
20 psi
40 mph |
4:20, eh !!!????
I was thinking there for a minute that you sparked up a fatty and ripped down the road at 40 mph....give or take a few....  
Don't believe everything you think....
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motoged
Elite Nomad
Posts: 6481
Registered: 7-31-2006
Location: Kamloops, BC
Member Is Offline
Mood: Gettin' Better
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| Quote: | Originally posted by tiotomasbcs
Is that what they call it--4-40?? I'm with the air down--20lb and 35mph. However, when driving my Odyssey it's slow, slow slow! Fill up the cooler
and fire a fattie! The Tacoma don't care but da Honda sys why hurry??  So
many variables but easy does it! Tio |
See....Tio gets it ....
Don't believe everything you think....
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bajamigo
Super Nomad
Posts: 1218
Registered: 6-17-2006
Location: Punta Banda, BC
Member Is Offline
Mood: hubimos llegado
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To summarize:
Traveling slowly accentuates the vibrations caused by a washboard road. The faster you travel, within reason, the smoother the ride will be as you
tend to ride on the tops of the washboard instead of sinking down into it.
Traveling "with" the washboard tends to be a bumpy ride. Traveling "against" it is usually smoother. That means traveling on the opposite side of the
road as you would normally. Do this only if you can clearly see ahead to avoid oncoming traffic.
Often the washboard portion of the road exhibits itself as two parallel tracks. It can sometimes be avoided by traveling in between the washboard
tracks.
Last, but not least, be aware if you travel too fast you can loose traction with the road surface and slide off to the side, especially on turns that
have washboard surfaces. So, if you're trying to avoid the vibration by traveling a bit faster than usual, be aware of the "grip" your vehicle has on
the road so you don't travel too fast for safety.
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ncampion
Super Nomad
Posts: 1238
Registered: 4-15-2006
Location: Loreto
Member Is Offline
Mood: Retired and Loving it
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It's interesting to hit the brakes firmly on a vehicle with ABS on a washboard road. It throws the ABS as the wheel speed is very irratic. Almost
eliminates braking if going fast.
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mtgoat666
Select Nomad
Posts: 18376
Registered: 9-16-2006
Location: San Diego
Member Is Offline
Mood: Hot n spicy
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in summary, driving on washboard surface is is not rocket science or brain surgery. use common sense! drive whatever pace makes you comfortable! if
it feels good, do it! don't drive faster than is safe!
always remember: yes we can!
p.s. don't drink and drive!
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DENNIS
Platinum Nomad
Posts: 29510
Registered: 9-2-2006
Location: Punta Banda
Member Is Offline
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| Quote: | Originally posted by mtgoat666
p.s. don't drink and drive! |
Will your silliness ever cease?
Famous quote:
"A road-trip without Pacifico is like a day without sunshine"
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bkbend
Senior Nomad
Posts: 693
Registered: 11-27-2003
Location: central OR or central baja
Member Is Offline
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| Quote: | Originally posted by mtgoat666
more interesting questions::::::
what wheel movement or driving style causes washboards?
do fast or slow drivers cause the washboards?
do particular vehicles cause more or less washboard formation?
should the responsible vehicles be cited/fined to pay for more frequent grading to maintain road?
are particular road beds better or worse at forming washboards?
why don't road contractors use better materials in road beds to prevent formation of washboards?
it seems to me that many road projects bring in crushing plants to prepare aggregate for road base, so why don't engineers specify better/best
aggragate for use in road bed?
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My observation is the finer the road material the less the washboard. Fine material packs into a harder roadbed than coarse gravel and slows down the
formation process.
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David K
Honored Nomad
Posts: 64848
Registered: 8-30-2002
Location: San Diego County
Member Is Offline
Mood: Have Baja Fever
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Those of you who remember Timothy Walker (TimsBaja.com) may recall on his site there was a link to the scientific explanation for why roads corregate
(become washboard). Perhaps some searching will bring back that link. In a nutshell, bad shocks (bouncing tires) cause the sand to colect in ridges
was what I recall that site said.
In Harry Lewellyn's 'Shifting into 4WD' he says it is from high speed pneumatic tires (bouncing)... (Poor shocks allow a tire to bounce excessivly)
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mtgoat666
Select Nomad
Posts: 18376
Registered: 9-16-2006
Location: San Diego
Member Is Offline
Mood: Hot n spicy
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the whole truth about washboards
After asking my question, i read the research. Info below seems to be generally accepted. Those of you that deny science, e.g. you global warming
denialists, should read no further! Also, if you distrust the french, a common affliction of global warming denialists, you should read no further!
"...neither tyres nor suspensions are necessary to obtain washboard roads, although of course, adding a spring, a dashpot, a tyre or an engine would
affect the size of the bumps. In other words, it is not because of the suspension of cars that washboard roads exist. The ripple wavelength is NOT
simply the speed of the wheel times the bounce frequency of the suspension, which seems to be a common belief.
Another interesting result is that the size of the wheel and the size of the grains has no influence on the pattern. The mass of the wheel does
however. ...using very fine sand (average size of 200 µm) and coarse grains (3 mm), we obtained an identical pattern."
from http://perso.ens-lyon.fr/nicolas.taberlet/washboard/
see also
N. Taberlet, S. Morris and J. McElwaine. Washboard Road: The dynamics of granular ripples formed by rolling wheels. Phys. Rev. Lett. 99:068003 (2007)
A.-F. Bitbol, N. Taberlet, S. Morris and J. McElwaine Scaling and dynamics of washboard road. Phys. Rev. E 79:061308 (2009)
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