Washboard

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

slammed41

slammed41

Joined
May 13, 2009
Threads
10
Messages
76
Location
Paradise, BC
i know...this isn't specifically about 60 series land cruisers, but it's happening to me in mine and i don't know where else to ask this question...

why does my soa bj60 dance around so much on wasboard...in particular, the rear end bouncing sideways? i find it rarely happens on slight upgrades, does happen on some washboard patterns on level roads and happens most frequently on downgrades. it's downright dangerous sometimes...on narrow roads with big drops, big ditches or big walls on the side, i'm forced to drive quite slow or risk getting tossed off.

my spring packs are made from stock leaves with one extra stock leaf inserted in each pack and the ride is quite smooth in most conditions. potholes and bumps do not create any adverse responses in the suspension...just washboard. the truck is riding on 16" wheels with 255/85R16 tires.

cheers to helpful replies!
 
I'm thinking it's a suspension issue. I run OME and have driven many-a-mile on washboard roads without any of the symptoms you described.
 
Shock absorbers? What do you have? How old are they? Tire inflation really high? Sounds like the rear end is too stiff but I'm no expert.
 
Sounds like the rear springs are too stiff / tire pressure is too low / shocks are dead. What's the condition of the 3 aforementioned items?
 
I agree with GLTHFJ60, except tire pressure too high. As soon as I hit gravel I air down to 18-20 psi. I let the tires absorb the washboard. Shocks could be too stiff, are they gas or oil? Or a combo of both?
GG
 
I can do 40 mph on washboard roads in my FJ62 with no problems. The suspension was completely stock when doing this. Although the washboards felt rough my rear end never lost traction like you are describing. I attribute this mainly to airing down. I run my tires around 20 psi when on washboards to help cushion the ride. If your tires are inflated to their maximum operating pressure then you are going to have a harsh ride and that could be causing the symptoms you are describing.

Don’t quote me on this but don’t newer Toyota trucks put one shock on each side of the rear axle? One front and one rear to prevent axle hop as with these symptoms described? If airing down does not help and shocks are relatively new I would try removing one shock and relocating it to the other side of the axle. Someone with more experience with Toyota trucks would have to chime in here.

Oh, btw, running fast on washboard roads caused my driver side caliper bolts to wiggle loose. This allowed my caliper to float freely on the brake rotor when braking instead of staying put and stopping. Moral of the story, check that your caliper bolts are torqued properly to 90 ft lbs.
 
You are in 4 wheel drive right? If not then I would think it would be better on the washboards.
Also wonder if you are loaded with gear in the back or empty. Maybe that could make a difference.

The only time I have gotten a little out of control on washboards was in 2 wheel drive.



Randy88FJ62 said:

Oh, btw, running fast on washboard roads caused my driver side caliper bolts to wiggle loose. This allowed my caliper to float freely on the brake rotor when braking instead of staying put and stopping. Moral of the story, check that your caliper bolts are torqued properly to 90 ft lbs.
Click to expand...


Because of this report about your calipers I went ahead and checked them before I went to death valley and I brought a few spares just in case.
 
If the road is in good shape other than the washboard, try speeding up and see if it settles down. The grid roads on the prairies up here can be hell if you are doing under about 40 mph, but smooth out above.
 
I drive washboard every day here in Alaska....... I end up with loose parts and a ton of crap built up all under my rig. My cruiser is pushing 25 years old and doesn't need that kind of abuse.
 
RockDoc said:
Try it and see ;)
Click to expand...
I agree.

The thing is that it gets the worst right before it smooths right out. I sometimes find it hard to push that little bit harder even though I know that it will get better & smooth out. They're called "4-40 Roads" for a reason.

The road that Randy had his brake incident on (Saline Valley Road) is about as bad as it gets south of the 45th, and that includes the infamous roads SW out of San Ignacio, Baja and from Ubehebe Crater up to Teakettle Junction.
I've not seen the AK washboards, but from descriptions and a few pictures they are about the same. The San Iggy road is about 50 miles long, so the AK roads (& presumably the Canadian roads too) get points for their exceptional distances.

All of that said, I mostly run street tire pressures off road. When it gets really technical I air down to ~20 psi. I say mostly because it varies with the vehicle that I'm driving. The Suburban wants 10 psi down from street, to ~40 psi, for off pavement driving. Patch is fine with it's normal 30 psi, and the DB is fine with it's normal 10-12 combo. I've not had my 60 on enough washboard to learn what it wants yet.

Having the correct spring rate for the loading is important, but good shocks are the total key to control and ride quality. To me a good shock comes from King, Fox, Bilstein, or SAW with no exceptions. No twin tube design (OME, Rancho, etc.) can match the deflective disc valving found in those mono-tube shocks.

What is happening is that the shock can't deal with the high frequency - low amplitude inputs. Most likely the result is that the oil has boiled and the shock 'fades', providing little to no damping of any sort so the suspension goes into resonance and is dancing around undamped. There's no vehicle control in a uncontrolled bouncing tire.

FWIW I've read that AK report on the generation mechanism of washboard. If that theory is correct, then low tire pressures exacerbate the problem. If you think if the tire as pushing up a "bow wake" of soft stuff ahead of it, which is more likely to keep pushing it ahead and off to the sides and which is more likely to roll over the "wake"? I contend that the harder tire will keep pushing it. Same with a skinny vs. a wide (AKA "Flotation") tire. The skinny will keep pushing. Once a tire rolls over a clump of soft stuff you have the first ripple of washboard. The next bloke who comes along with poor dampers will deposit the bit of soft stuff that his tires were pushing and the first ripple will set up a resonance in the suspension to start the second ripple. And on and on we go.....
 
Last edited:
Drive washboard roads all the time - usually a lot faster than anyone else. I've never had the back end cut loose in an unexpected manner. Sprung under, OME, two extra springs in rear, one extra in front, 35's, heavy truck (7,000+- depending on fuel and gear). Every bolt on the truck gets loose and lots of other maintenance, including a broken U-bolt, but I've never been left stranded.

Check that your u-bolts are tight, shocks. Tire pressure, but I just did 400 miles of washboard twice, once at 45lbs and then at 36lbs, with no real difference, other than my tires are cut to pieces. I just try to drive faster than the dust cloud and not kill myself along the way. Perhaps some sand bags in the rear just to put a dent in the fuel economy :).
 
ntsqd said:
I agree.

... that includes the infamous roads SW out of San Ignacio, Baja ...
Click to expand...

hahaha, done that road plenty of times.







I agree with many of the others here that speeding up, and better shocks are key to feeling more stable on the washboard. and yeah, caliper bolts do have a tendency to loosen...

not all washboard is the same, and conditions are always changing, but as a general rule for me - faster, good shocks, tight ubolts.

HTH
 
I have to say that on washboards and other rough dirt roads is where OME really shines. The first time I drove in the outback of eastern Oregon, I couldn't stop smiling...
 
Well, as you can tell from reading all the posts, everybody has their opnion. It's a combination of many factors, tires, shocks, speed, weight, the size of the washboards just to name a few. Just change SOMETHING, tire pressure, shocks, speed, whatever untill it gets better. Speed is my favorite cure, but I know that airing down does help.
 
It really does boil down to the type of road. The wash board we have in Alaska is like no other.
The base of the road is trees layed down on their sides. YES, TREES! This is the foundation of our road. Under those trees is bog! On top of the trees is a layer of gravel or rock. The washboard is heavy with the trees pokeing out here and there. Its more of a safety issue than a smooth riding issue going fast! i do understand it will smooth out going faster.
 
You must log in or register to reply here.

Users who are viewing this thread

Total: 1 (members: 0, guests: 1)

Share this page

Back
Top Bottom