Desert Dan
Explorer
Air Down and find the speed and pressure that gives you the best ride on wash board roads.
Be careful on turns and "crowned" roads.
Be careful on turns and "crowned" roads.
Handling Rough and Washboarded Roads at Speed
- Thread starter carbon60
- Start date
LexusAllTerrain
Expedition Leader
x2:sombrero:
cruiser guy
Explorer
75kph on potholed roads aired down sounds like a tire salesman's dream!! Here in Africa where badly potholed roads are pretty standard there are folks who are simply drivers that blast down the road and the vehicle owners pay for new tires and suspension repairs or you take your time and enjoy the scenery and save your tires and suspension, not to mention your own body.
Budget for plenty of bushing replacements and suspension repairs in the mix as well.
The higher the speed on crappy roads the more $$ for repairs and tires. It's a call each one has to make themselves.
I find my '60 series with 34"x9.5"x15" Super Swampers (Load Range "C") rides MUCH better than the F350 the mission has that rides on standard 235/85R16 (Load Range "E") street tires when running the same speed. Both are aired up to the sidewall rating. The F350 goes through tires faster probably because others are driving it and blasting down the roads far faster than they should. 90% of the travel is badly potholed African roads. I think the high sidewalls and increased room for flex in the sidewalls of the Super Swampers is a contributing factor. Get on the highway and the Super Swampers are not so nice.
When the sidewalls start to bulge it is too late to save the tire. A blowout is not a question of "If?" but "When?" at that point. You'll see 'cause at 75kph on potholed roads you'll get there!!
Budget for plenty of bushing replacements and suspension repairs in the mix as well.
The higher the speed on crappy roads the more $$ for repairs and tires. It's a call each one has to make themselves.
I find my '60 series with 34"x9.5"x15" Super Swampers (Load Range "C") rides MUCH better than the F350 the mission has that rides on standard 235/85R16 (Load Range "E") street tires when running the same speed. Both are aired up to the sidewall rating. The F350 goes through tires faster probably because others are driving it and blasting down the roads far faster than they should. 90% of the travel is badly potholed African roads. I think the high sidewalls and increased room for flex in the sidewalls of the Super Swampers is a contributing factor. Get on the highway and the Super Swampers are not so nice.
When the sidewalls start to bulge it is too late to save the tire. A blowout is not a question of "If?" but "When?" at that point. You'll see 'cause at 75kph on potholed roads you'll get there!!
Well, I guess I'm going to do a total of 2500 km a year in that kind of road, so hopefully that won't be too bad.
Going slower means that it takes a long time to get to the places I want to see, and I'm often cramming trips into a single weekend.
But, of course, you're point is very valid.
Thanks,
A.
Going slower means that it takes a long time to get to the places I want to see, and I'm often cramming trips into a single weekend.
But, of course, you're point is very valid.
Thanks,
A.
coax
Adventurer
Lets see. They are the fox 2.0 remote res 10" with the stem tops. The fronts had the lower mount changed out to be a stem as well so they are bolt in. The rears had the lower mount changed out as well so that instead of a heim it uses a standard bushing. IIRC the fronts come out to 14.8/24.8 length, and the rears are 15.25/25.25. (Rear are longer since the stem mount conversion on the bottom shortens up the front a bit.) Puts them a hair shorter than the OME L's. I found they work about perfect with the heavy springs and balance nicely for up/down travel. I also didn't need to drop bump stops to avoid over compression either. I know a number of folks are going 12/14" shocks, but I honestly don't see how they are not over compressing the shocks without major bump drops, especially after converting from eye to stem.
As for valving Down South did a flutter stack on them. Don't recall what the exact numbers were, but I think they are somewhere in the area of 45/70 front and maybe 50/80 rear. Ride was vastly improved over the OME shocks, though still a bit harsh when unloaded, but I mostly attribute that to the high spring rate (that the shocks won't do anything to solve)
nuclearlemon
Adventurer
i've done the air down thing, but not drastically...even going to 25psi makes a huge difference in ride. but as mentioned, it rattles things loose. watch for control arm bolts and brake pad pins to come loose, along with other things. everytime you stop, do a cursory glance to make sure everything's still where it's supposed to be
Hill Bill E.
Oath Keeper
I switched to Bilstein 7100 w/remote res on my TJ, and it made a world of difference over the old shocks (Skyjacker monotube)
Since you already have remote res, there shouldn't be a problem with shock fade. You may need to have the valving changed.
I don't recall offhand what mine are, the shop I bought them through talked to Bilstein, sent them a pic of my rig/what I normally haul for gear/what I do with it/etc, and they recommended the valving.
It's a bit on the stiff side when on the hi-way and empty, better when loaded down for a trip, and absolutely great off road.
I was really impressed with them at high speed, (55-65 MPH) on a short run we do in Moab every year.
Normally, I couldn't maintain control over 35-40 mph once the shocks got hot, but had great control with the Bilsteins.
Washboard roads just plain stink for any kind of speed, and the shorter the wheelbase, the worse the ride.:coffeedrink:
Since you already have remote res, there shouldn't be a problem with shock fade. You may need to have the valving changed.
I don't recall offhand what mine are, the shop I bought them through talked to Bilstein, sent them a pic of my rig/what I normally haul for gear/what I do with it/etc, and they recommended the valving.
It's a bit on the stiff side when on the hi-way and empty, better when loaded down for a trip, and absolutely great off road.
I was really impressed with them at high speed, (55-65 MPH) on a short run we do in Moab every year.
Normally, I couldn't maintain control over 35-40 mph once the shocks got hot, but had great control with the Bilsteins.
Washboard roads just plain stink for any kind of speed, and the shorter the wheelbase, the worse the ride.:coffeedrink:
adventureduo
Dave Druck [KI6LBB]
I'll echo the better shock statement as well. We run Fox shocks setup specifically for our trucks weight. I can literally drive off a curb in the city and you hardly know it. There's options such as Icon and Radflo out there now i believe as well.
Yes, to have a look for your car at a daily base on an extended trip. I see one evening that 4 of 6 screws from the roofrack was loose. Unfortunately i dont check everything - and loose my rear numberplate in Namibia.
With a weight of near 4to i had not tried to lower the air pressure much...
Surfy
007
Explorer
This may not apply to a 1996 land cruiser....
I know that removing swaybars on IFS vehicles drastically improves the ride on washboards. The sway bar links the two sides and one pot hole sends a shock to the opposite side. When you unlink the two sides they can act independently and the ride improves. (This can make high speed maneuvers more dangerous as it increases body roll).
I know that removing swaybars on IFS vehicles drastically improves the ride on washboards. The sway bar links the two sides and one pot hole sends a shock to the opposite side. When you unlink the two sides they can act independently and the ride improves. (This can make high speed maneuvers more dangerous as it increases body roll).
REDrum
Aventurero de la Selva
Do not air down <20PSI, as others have noted it increases risks to sidewalls, beads and puncture (generally I don't go <25 hot). Rather, explore, adjustable dampers w/ remote reservoirs (if only 1-way adjustable). They will get hot after 50K of washboard. Adjust compression rebound to suit road conditions. Also, since you have lifted, pay close attention to your alignment: camber and toe. Stay within OEM specs and make sure you don't have toe out in the rear or you could swap ends fast on sweeping washboard turns.
Happi Trailz
Happi Trailz
What happens when shocks get hot? They get softer? I'll need to stop for a bit to let them cool?
How do I verify alignment, camber and toe? (Sorry, I'm completely new to this!)
Thanks for the great replies!
A.
coax
Adventurer
Shocks fade when the get too hot. The more oil, the longer they take to fade, as they can disipate more heat. (hence remote reservoirs, bigger diameter shocks. Remotes provide other benefits as well, but more oil is one.)
Here's a good explanation of fade from pirate. http://www.pirate4x4.com/tech/billavista/coilovers/Part_1/
As for alignment, since you have a solid axle, toe is the only thing easily adjusted. Caster is done via brackes, bushings, etc. If your camber is off you have big problems (bent axle, busted trunion bearings, bent spindle, etc) If you have out of spec toe in the rear you have REALLY big problems.
An alignment shop is the only way to get a good reading on those three measurements.
Here's a good explanation of fade from pirate. http://www.pirate4x4.com/tech/billavista/coilovers/Part_1/
pirate4x4 said:
As for alignment, since you have a solid axle, toe is the only thing easily adjusted. Caster is done via brackes, bushings, etc. If your camber is off you have big problems (bent axle, busted trunion bearings, bent spindle, etc) If you have out of spec toe in the rear you have REALLY big problems.
An alignment shop is the only way to get a good reading on those three measurements.
grimbo
Explorer
Try different speeds, 75 sounds way too fast. You will find that a different speed will suit that particular section of washboard.
We have heaps of badly corrugated roads here in Australia. No two roads are the same. Some will require low speeds to negotiate while others you can tackle with speed. It's finding the balance between fast enough without shaking the car to bits and the faster you go the more vibrations you are introducing to the vehicle and the more chance things will shake loose not too mention the likelihood of a sudden lose of control
We have heaps of badly corrugated roads here in Australia. No two roads are the same. Some will require low speeds to negotiate while others you can tackle with speed. It's finding the balance between fast enough without shaking the car to bits and the faster you go the more vibrations you are introducing to the vehicle and the more chance things will shake loose not too mention the likelihood of a sudden lose of control