Driving on gravel roads, use 2wd or 4wd ?

[trikebubble]

I do not want to derail this thread, but I've never seen a good explanation of what actually causes "washboard". I've heard tire slip, wheel hop, wind, water and gremlins, but nothing explains (to me) the almost perfectly spaced ridges that go completely across the road for such long stretches,sometimes for miles.

cwd

Russians. Russians cause washboard. It's a well known fact....

I go 2wd until I feel the need to for 4wd.

 

[PackRat]

To answer your question based on the photos you posted.....2WD is fine on the roads in the photo as far as I can see, the speed you use is determined by YOU when you start out and if you feel some resistance or "floating" then you might find the "sweet spot" in terms of MPH and you are good to go.

 

[klahanie]

Klahanie...sorry we stole the thread....washboard isn't allowed in the great north, is it ?

No worries. We export ours to OZ. In return we can use some of their slang...
---

Russians. Russians cause washboard. It's a well known fact....

LOL, mine was dentists but yours is better
---

Searching "washboard" I found this comment which I'll add here with the replys :
"Our preference is to travel in 2WD on corrugated or dirt roads that don't require the extra traction that 4WD affords. We find that 4WD 'pulls' the car around the corners and fastidiously holds it's line where the slight looseness of 2WD makes for a less fatiguing ride. It's just personal preference. If safety is paramount then select 4WD."

Found here :
http://outbackcrossing.com.au/FourWheelDrive/Conquering_the_Corrugations.shtml

It touches separately on fatigue and safety both of which are increasingly on my mind as I age ...

Thanks again for all the comments.

 

[rubberlegs]

Our Toyota manual says to use 4WD for 10 miles per month, to lube those parts. I wonder how many people do that? You wouldn't do that to drive to the grocery store all month.

 

[ckent323]

We have a 20 foot wide gravel over shale access driveway that is side by side with a neighbors 15 foot wide gravel over shale driveway such that it appears to be one 35 foot wide gravel street.

There are three homes that share the 20 foot wide portion and there is one house that owns the 15 foot wide portion. The length of the shared section is about 220 feet to where the 20 foot wide side ends and the 15 foot wide side continues on another 300 feet to the last house. We live in the first house off pavement.

We and the residents of two other homes that use our 20 foot wide side all drive slowly on the gravel, mostly to try to keep dust production minimal.

One of the residents of the home accessed by the 15 foot wide side (a Woman who will go unnamed) likes to drive faster on her side. Curiously her side develops a washboard surface (as does a particular spot on our side where she crosses over onto our side) whereas our side remains smooth. Periodically one of her male relatives comes over and smooths out the washboard with rake and shovel. It reforms the same as before after a couple of months.

The drivers on our side probably stay in the 5 to no more than 10 mph range. I estimate that the faster driving neighbor is typically moving at 15 - 20 mph. She also generates a fair amount of dust in the dry season.

My conclusion after years of observation of this "phenomena" is that the development of the washboard is related to slipping of the drive tires and bouncing of the suspension. It seems there is a threshold speed above which the wash boarding forms and then gets worse and worse.

P.S. She is a nice lady in most all regards but refuses to slow down even though we complain about the dust she generates. I refuse to help her male relative smooth out the washboard because it slows her down once they develop. I have explained this all to him and he understands and knows I will help him with most anything else he needs a hand with.

I display my joy at seeing her suffer from her self induced annoying ride, when I am outside and see her bouncing along, by smiling at her and waving as she drives by.

 

[Advmoto18]

Our Toyota manual says to use 4WD for 10 miles per month, to lube those parts. I wonder how many people do that? You wouldn't do that to drive to the grocery store all month.

Just like the human body...you have to exercise those joints.

I even run the AC in the house once/month in winter to move the refrigerant through the system since it is a lubricant as well.

I learned more from old military power plant/airframe mechanics then anyone else. If parts are not exercised on a regular basis, they fail in short order, or, when you need them to perform the most.

 

[craig333]

Making me wonder if taking my TF out of service in the winter was a bad idea. Still haven't found anyone to service it.

 

[Mickey Bitsko]

Op , imho, running a gravel road in 4x doesn't hurt a thing.

 

[PackRat]

Oh man, if you enjoy watching the misery of others....especially after numerous attempts to get her to slow down, that might mean you are feeling a little "schadenfreude" !

In this case her misery is self-inflicted and as such, watching her bouncing down her section of the "road"

A washboard road may have its hills and valleys at the correct spacing for one vehicle to ride up on both axles and down on both axels which gives a basic bounce but depending on the wheelbase of the vehicle, one may act like that while the next vehicle surfs down the road like it had a million small speed bumps.

In either situation, it is an annoying and uncomfortable ride especially at a speed higher than a slow crawl. I guess after hitting some higher MPHs on the highway she just can't get used to the slow pace needed to not only avoid dust, but to keep everything in her car as well as her passengers from a bouncing, bucking rind.

The grandkids probably think its like a Carnaval ride or something.

 

[Mighty Dodge Ram]

Unless it’s really hard packed I slip into 4-hi on dirt roads for the added traction. Washboard? Definitely 4WD.

 

[Smokecreek1]

I spent a good deal of time for 30 or so years, driving on those gravel roads during my career in BLM as a part of my job description. In addition, I spent many miles of play time on those same roads and there is no one right answer as to whether or not you use or don't use 2WD or 4WD because ever road and/or driving condition requires a different solution. You drove those roads as fast as driving conditions and your body and shocks allowed allowed- and everyone and each vehicle i different. I think the rule i remember the most is always think ahead-and be in the right gear for that driving situation -shifting in the middle of a stream or half way through a mud hole is a always bad idea!

I was taught to use 2WD most of the time, shift into my granny gear (when you had one) when you needed to go slow and only use 4WD when it got real bad. It seems to me, one of the rationals behind not using 4WD was gas consumption-use more gas in 4WD. We had yearly safe driving instruction classes and the government thought rather badly of us wrecking their rigs so we learned how to use them the right way, or pay for their repair. Today I drive slower than I used to, but maybe that's retirement and my body telling me to take it easy !

I first learned to drive from my dad and friends ( I grew up at Lake Tahoe and in Northern California) and it was not until I got in the army that I learned to drive the right way-the army way(?) on those gravel and wash board back country roads. I remember when we were on maneuvers at Yuma Proving Grounds in Arizona before our unit was shipped overseas and we had to drive those wash board roads all the time. Well being young and stupid "GI's" we got tired of of all the beating we were taking on the roads, and when the NCO's were not around decided to see if going slow or fast was the best way to drive out there with our jeeps, 3/4 and 21/2 ton trucks and it seemed like you could go faster with the heavier trucks than the lighter ones (jeeps were real bad on those roads)-now what it did to the shocks may have been and other story. Any way you did it, it still were beat you up and I know that that's not much of a test, but it is a start. Anyway, driving out there is a learned process and smart driving is safe driving and safe driving means you might make retirement!

Smoke

 

[cwdtmmrs]

Smoke, that is one of the best posts I have read on the forum!

cwd

 

[Andy Douglass]

As a few have said already, I don't use 4x until I need it, or if I want to move the 4x components around a little bit as maintenance. I was taught this by numerous friends that had a lot of wheeling experience. I'm talking about guys who could out wheel most 4xs in their girlfriends' front-wheel drive rice rockets.

 

[noteven]

06 Dodge 3500 diesel manual trans - the front driveline and diff turns all the time so I often engage front wheel power on loose surface roads especially when lightly loaded or towing to stop rear wheel slip. If all vehicles travelling a gravel road used all wheels drive to stop tire slip warshboard would not form. Once it does start the hopping of powered wheels continues the process. As the tires hop off the road momentarily, the vehicle slows so “fast” drivers add power, spinning more. These folks often “don’t bother” with 4wd as well. Wastes gas one told me.

 

[Chrish]

I always use 4 wheel drive on loose gravel and dirt due to better control.

I came across a flipped truck once on a gravel\dirt road and encountered the lady driver a mile down the road walking. Gave her a ride to town to the paramedics office. She was kind of out of it and later learned she broke her wrist.

She was in 2 wheel drive at the time and got into a float loss of control until she flipped.

She was lucky as she as managed to stay on the road and avoid the steep drop off.

Imo, safety trumps gas mileage savings.

http://www.roadcover.co.za/safe-driving-gravel-roads/

 

[klahanie]

^ Thanks for that, a good reminder to always take care and be aware that accidents can happen at any time.

Your post is exactly the sort of experience I was curious about. I think sometimes accidents result from of an accumulation of factors, 2wd vs 4wd might just be that final, critical one...

 

[ntsqd]

Sounds to me more like the driver ran out of talent. Easy to do, particularly when conditions abruptly change with no warning. I wasn't there, so I've no idea if 4WD would have made a difference in regaining control. When in doubt, slow down.

 

[Vic Harder]

I was driving with the camper on a gravel road (Smith Dorien in Kananaskis Country, Alberta - highly recommended) last week. Speed limit is 80 kph. That's "slow" for some people, stupid fast for others ... depending on talent and vehicle and conditions.

And even then it changes fast. I hit a few bigger potholes in a row, and the truck got very skittish, in 4wd, below speed limit, with a track driving experienced and trained driver. No accident, but it could have gone very differently.

Be safe out there.

 

[karsonb]

I was taught that 4WD is to be utilized to get UNstuck. If you have it engaged when getting stuck, usually it is much harder to extracts oneself. There have been rare occasions when 4WD was necessary to proceed with caution on bad surfaces, but not too quickly. It is so easy to get much “stucker” with 4WD engaged all the time when it doesn’t have to be engaged.

 

[ntsqd]

That is a good RoT, but there are always exceptions.
Silver Cyn Rd. is one that comes immediately to mind. I used 4WD-Lo going down it to keep the vehicle's speed under control. This a graded dirt road. NOT recommended for trucks with campers.
Also used 4-Lo going up the road between Silver Peak and Dyer Valley. Graded county road that is so steep that I used 4-Lo to keep the engine & trans from over-heating.
Same with the road up to Hurricane Ridge in the Carrizo Plain. Too steep to drive something heavy up w/o being in 4-Lo.