Optimizing suspension for washboard?

Martinjmpr

Wiffleball Batter
I really haven't done much "off roading" this year but our last camping trip of the year took us to the SW region of Utah near Bryce Canyon (we camped at Kodachrome Basin State Park.) One of our "day trips" was a drive out to the slot canyons along Hole-in-the-rock road in Grand Staircase Escalante National Monument (GSENM.)
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Any of you who have driven HITR know that it is about 55 miles of dirt. The last 7 miles or so require a fairly high clearance vehicle and low-range 4wd is definitely a plus (although not absolutely required unless it's wet.) Certainly I appreciated having low range both for ascending and descending the rock ledges and steps there as well as the stretches of deep sand.
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But, as we drove along for miles and miles and miles and miles of dirt, the one thing that occurred to me was how common washboard road is in the Southwest. And I got to thinking about how most of us think of "suspension modifications" in the sense of either providing more lift (for bigger tires to get over obstacles) or more articulation (again for slow travel over big obstacles) but at least here in Colorado I have very rarely heard about anyone modifying their vehicle to perform better on long, extended stretches of washboard.
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Now I know some 'desert racing' vehicles have long travel suspension that is good for high speed travel over rough desert roads, so is that the same kind of adaptation needed for washboard? I did have the foresight (after about 20 bone-jarring miles) to pull over and air the tires down to about 20 - 25 PSI and after that, the ride improved noticeably. But it was still pretty rough and honestly I'm a little bit surprised that I didn't have any electrical connectors that broke or other parts that failed after that long, 110 miles of uninterrupted dirt, most of it very washboard-y.
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WRT speed, I know one thing that people like to say is "take washboard at high speed and you will float over the top of the washboard and have a smoother ride." Well, while this may be true, "floating across the top of the washboard" is also akin to driving on very slippery ice in terms of it being very easy to lose control and have a nasty rollover or other accident.
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Having said that, our group coming in to the slot canyons had 5 vehicles but by the time we got down to HITR we only had 3 and made much better time coming back, and I did notice that the higher speeds seemed to have made the ride marginally more comfortable. Just for reference, it took us 2 1/2 hours to get from the slot canyons to HITR (31 miles), but then after we were done at HITR, it took us the same 2 1/2 hours to get all the way back to Escalante (55 miles.)
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Still, I know it's going to be a long time before my wife consents to another ride down a long washboard road unless I can figure out a way to make the ride less miserable for the both of us.
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So my question would be, what kind of modifications can be made to make a vehicle more compatible - or at least, less miserable - for long stretches of washboard road? For example, would softer shock absorbers be better to soak up the bumps? Should I have lowered my tire pressure even more, to, say 15 PSI? What have others done when faced with long stretches of rough washboard?
 

Martinjmpr

Wiffleball Batter
Also curious to know if anyone has compared how a vehicle with a fully independent suspension compares to one with a solid rear axle on washboard? I know my wife's solid-front-axle Jeep Wrangler was miserable on washboard (though that also may have been due to the leaf springs and/or the short wheelbase.)
 

Comanche Scott

Expedition Leader
my bil's on my 2500 tell a different story.air down.waaay down.

x2 :beer:

Best mod is airing down for washboard.

I noticed the new Falken AT3W is designed to carry heat away from the area right above the bead when aired down. That is a beautiful thing. :)

I've had bead separation on certain tires when running aired down over long distances, at speeds above 50mph.
So caution on speed and distance when aired down is a good idea.
 

offthepath

Adventurer
Yeah.... I generally keep the 35in tires on the f250 at 50 psi and it rides great. When I switched shocks it was night and day. Very happy with the shocks.

I have an OME suspension on my montero and although overall much much smoother (obviously), unless I keep the tires below 25 psi the wash boards can get rough.
 

fordracing19

Observer
My stock f250 beats me up but my 4runner with the adjustable Icons front and rear eats it up. I set the front to 4 and back to all the way soft.
 

Betarocker

Adventurer
My not so stock F350 soaks up washboards decently. Long wheelbase, large tires with tall sidewalls aired down, long travel, and moderately higher speeds. Using 4wd helps prevent the front wheels from diving down into the troughs.

When the washboards become whoops, the speed drops to a crawl.
 

Regcabguy

Oil eater.
My 2007 Ram w/Kings,minipaks,35's and my popup transmits a lot of washboard. Airing down to 25-30 psi works wonders.
 

CMARJEEP

Observer
Suspension will only help so much on washboard. Each road and vehicle combination will have a different optimal speed to reduce the effects of it. You just have to find that speed. In addition, airing down helps and also like others have said putting in in 4wd.
 

Desert Dan

Explorer
Air down and 4WD engaged. Find a "sweet spot" for your rig my 4 R is 40 50 MPH depending on the wash boards!

The 4WD helps with traction and control on washboard turns and uphill.
 

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