Events/Trails Trip Report: Death Valley and a Wrecked 80... (2 Viewers)

[BILT4ME]

First off sorry to hear about the truck, and glad no one was hurt.

I'm surprised no one has mentioned loose/sloppy steering as a potential contributor here. With maybe 5-10 degrees of slop between the steering wheel engaging from one direction to the other (as I see on my 94 with 210k+ miles) it takes some finesse to get around sweeping turns in a smooth manner. I am guessing that is just par for course with older high mileage vehicles. As an example when going around a sweeping right hand corner you need to carefully control how much rightward pressure you have on the wheel to keep desired track; turning wheel to provide left input and then hooking back up in right turn results in a lot of back and forth swerving. I noticed this exact thing when my wife drove a stretch across the Sierras on I80 (staying within the lane but constantly going between left and right stripes). I am thinking that you combine new/inexperienced driver, sloppy steering, and high COG and this is what can happen...

Mine has zero slop in it and it has 269K on it. I have replaced the tie rod ends in the last 48K miles.

Check your knuckle studs on the lower right knuckle! This is VERY important! I had SLIGHTLY loose steering and discovered that 3 of the 4 studs were MISSING and the last one was about to fall out (only in about 2 turns yet) I tightened it back up as best I could and drove very gingerly home. It still had less slop than every other solid axle 4x4 I've ever driven, so I didn't think there was a problem.

Your truck should NOT have that kind of play.
Knuckle Studs
TRE's
Steering Gear
Wheel Bearings
Track Bar Bushings

 

[LS1FJ40]

349k, 2” lift, zero steering play. Check your chit!

 

[JohnnyFish]

First off sorry to hear about the truck, and glad no one was hurt.

I'm surprised no one has mentioned loose/sloppy steering as a potential contributor here. With maybe 5-10 degrees of slop between the steering wheel engaging from one direction to the other (as I see on my 94 with 210k+ miles) it takes some finesse to get around sweeping turns in a smooth manner. I am guessing that is just par for course with older high mileage vehicles. As an example when going around a sweeping right hand corner you need to carefully control how much rightward pressure you have on the wheel to keep desired track; turning wheel to provide left input and then hooking back up in right turn results in a lot of back and forth swerving. I noticed this exact thing when my wife drove a stretch across the Sierras on I80 (staying within the lane but constantly going between left and right stripes). I am thinking that you combine new/inexperienced driver, sloppy steering, and high COG and this is what can happen...

I have the same condition in my 235k LX. I'm about to replace the tie rod ends in the hope that it will improve.

 

[midfat]

I love to analyze vehicle dynamics following a crash. Can't help it. Here's my hypothesis...

Approached the crest of the hill at a moderate speed of around 50mph or so. Being a natural terrain road, the drop was a little more abrupt than what most are accustomed to. Thus, the truck "got light" after the crest. Now, if the road bent, even a little, the driver inevitably dialed in some steering in prep for the turn. But with the suspension partially unloaded because of how the road fell away underneath, too much steering was given. And here's the first significant reactionary event. As the vehicle reconnected with terra-firma, the suspension went from light load to heavy load - meaning the suspension was momentarily carrying MORE weight than the overall vehicle (due to compression). With even the slightest bit of steering angle, the front end would bite under load and the truck would almost immediately begin to rotate or oversteer a little. On a regular road, this probably wouldn't have been a big deal, but given the low traction, gravel surface, this would be greatly exacerbated. And now for the second significant reactionary event. At the moment the truck began to oversteer, the driver most likely responded with an immediate and abrupt lift off the throttle. This is when bad went to way worse. Lifting off the gas in a slide will ADD rear momentum by transferring load out of the rear springs. The releasing spring energy has to go somewhere. Most will go to the front and add more load to the steering wheels, but some will also contribute to rotation because an object in motion likes to stay in motion. It didn't help that the center-of-gravity was high given the combination of suspension lift and loaded roof rack. Counter-steer at this point would be all but futile unless you know when to instantly add LOTS of skinny-pedal back into the mix. Welcome to the "Skandenavian-flick," but without the necessary stomp-and-steer followup. Sir Issac Newton was in the driver's seat that day.

Again, really glad all are okay.

(P.S. For those of you who like to drive without sway-bars, God help you in a situation like this. You'd probably be barrel rolling for days.)

 

[Shoredreamer]

When I was there looking over the wrecked truck, I noticed it had been lifted but didn't see any means of caster correction (bushings or plates) so maybe more likely twitchy steering rather than sloppy steering.

Looks like it. Really glad nobody got majorly hurt.

For Sale - OME Castor Correction Bushings for 80

 

[mudgudgeon]

I love to analyze vehicle dynamics following a crash. Can't help it. Here's my hypothesis...

Approached the crest of the hill at a moderate speed of around 50mph or so. Being a natural terrain road, the drop was a little more abrupt than what most are accustomed to. Thus, the truck "got light" after the crest. Now, if the road bent, even a little, the driver inevitably dialed in some steering in prep for the turn. But with the suspension partially unloaded because of how the road fell away underneath, too much steering was given. And here's the first significant reactionary event. As the vehicle reconnected with terra-firma, the suspension went from light load to heavy load - meaning the suspension was momentarily carrying MORE weight than the overall vehicle (due to compression). With even the slightest bit of steering angle, the front end would bite under load and the truck would almost immediately begin to rotate or oversteer a little. On a regular road, this probably wouldn't have been a big deal, but given the low traction, gravel surface, this would be greatly exacerbated. And now for the second significant reactionary event. At the moment the truck began to oversteer, the driver most likely responded with an immediate and abrupt lift off the throttle. This is when bad went to way worse. Lifting off the gas in a slide will ADD rear momentum by transferring load out of the rear springs. The releasing spring energy has to go somewhere. Most will go to the front and add more load to the steering wheels, but some will also contribute to rotation because an object in motion likes to stay in motion. It didn't help that the center-of-gravity was high given the combination of suspension lift and loaded roof rack. Counter-steer at this point would be all but futile unless you know when to instantly add LOTS of skinny-pedal back into the mix. Welcome to the "Skandenavian-flick," but without the necessary stomp-and-steer followup. Sir Issac Newton was in the driver's seat that day.

Again, really glad all are okay.

(P.S. For those of you who like to drive without sway-bars, God help you in a situation like this. You'd probably be barrel rolling for days.)

I think that's a fair speculation. Add body roll due to 3" lift and high COG, and it's exacerbated more so.

 

[landcrshr]

Looks like it. Really glad nobody got majorly hurt.

For Sale - OME Castor Correction Bushings for 80

Good find.

Add zero caster to the list of contributing factors.

 

[landcrshr]

I love to analyze vehicle dynamics following a crash. Can't help it. Here's my hypothesis...

Approached the crest of the hill at a moderate speed of around 50mph or so. Being a natural terrain road, the drop was a little more abrupt than what most are accustomed to. Thus, the truck "got light" after the crest. Now, if the road bent, even a little, the driver inevitably dialed in some steering in prep for the turn. But with the suspension partially unloaded because of how the road fell away underneath, too much steering was given. And here's the first significant reactionary event. As the vehicle reconnected with terra-firma, the suspension went from light load to heavy load - meaning the suspension was momentarily carrying MORE weight than the overall vehicle (due to compression). With even the slightest bit of steering angle, the front end would bite under load and the truck would almost immediately begin to rotate or oversteer a little. On a regular road, this probably wouldn't have been a big deal, but given the low traction, gravel surface, this would be greatly exacerbated. And now for the second significant reactionary event. At the moment the truck began to oversteer, the driver most likely responded with an immediate and abrupt lift off the throttle. This is when bad went to way worse. Lifting off the gas in a slide will ADD rear momentum by transferring load out of the rear springs. The releasing spring energy has to go somewhere. Most will go to the front and add more load to the steering wheels, but some will also contribute to rotation because an object in motion likes to stay in motion. It didn't help that the center-of-gravity was high given the combination of suspension lift and loaded roof rack. Counter-steer at this point would be all but futile unless you know when to instantly add LOTS of skinny-pedal back into the mix. Welcome to the "Skandenavian-flick," but without the necessary stomp-and-steer followup. Sir Issac Newton was in the driver's seat that day.

Again, really glad all are okay.

(P.S. For those of you who like to drive without sway-bars, God help you in a situation like this. You'd probably be barrel rolling for days.)

We could speculate all day.......so I will too!

You are thinking what I was thinking, but there's another piece to the scenario. That left turn is actually a fork in the road, the lesser road goes straight ahead, and fakes you in to going straight. Therefore I doubt the driver "dialed in" any prep for the turn. I'm thinking the turn was purely reactionary/evasive.

 

[Lowbudgetlc100]

Wow Richie thanks for sharing your story. And luke from 4x4labs for helping you out.

 

[mesa man]

I've not heard truer words of wisdom I'll to that!@terrx

 

[mesa man]

Driving saline valley road is a state of mind. If it's already at the springs or you're trying to keep up with friends you won't be able to get there fast enough. Besides increasing speed to smooth out the bumps I've also found this to be true: the road seems smoother when I go slower, roll the windows down, get the right music on, open a cold beverage and look at stuff other than the next obstacle coming at 50 mph. I still get to the springs in time to make dinner and the only thing missed is sitting around yapping for an extra hour about how knarly the road was or wasn't.[/

 

[elripster]

When my truck was stock, it would have a very neutral 4 wheel slide response when pushing it through a corner. After the lift it had a strong tendency to swing out the rear end - too much oversteer. This would make itself known on wet roads, dirt roads, or low traction situations in general. As an engineer who has designed a few chassis from scratch and the likes I have a fairly solid understanding of camber, roll stiffness, etc.. and the impacts on vehicle dynamics. Because these trucks have solid axles front and rear camber effects are negated. Thus, I had suspected that the rear axle had too much roll stiffness but after taking dirt roads with and without my rear sway bar connected I can presently make the oversteer come/go which to me bolsters the hypothesis that roll stiffness induced oversteer is occurring.

This link sums up in simple terms the impacts of roll stiffness... Vehicle Dynamics - Cause and Effect Guide - Trackpedia In a nutshell, the axle that is resisting roll the most will side first all held equal (in IFS/IRS systems all is not necessarily held equal...in our case it is). You really want the front axle to slide first or at least a little more than the rear axle.

For some more background, I started with OME heavies front and rear. I switched to OME mediums on the rear axle but the oversteer did not change. Reading up it seems that the spring rates are the same between the two, it is just that the mediums are shorter. This explained the lack of change in oversteer. The added camber make the truck less "nervous", but when turning, the rear axle would still slide first.

With the rear bar disconnected the oversteer is more of a 4 wheel slide with light understeer which is ideal. However, I now have more body lean which is not ideal. The ideal solution would be to add a stiffer front bar and retain the rear. I am browsing Summit for an option.

Reading how the vehicle instability occurred in this accident, it sounds exactly like how my truck handles with the rear sway bar in play. I am fortunate enough to have had the type of driver training where the trainer locks up the rear wheels via the ABS and throws the car into a spin from which I have to recover so I am fairly on top of oversteer situations ranging from dry pavement to glare ice (very different correction required). However, 99% of us are not and thus rely on proper suspension tuning (or today traction control) to leave the vehicle in a controllable state when traction limits are pushed (new vehicles use software to do this). AWD vehicles like 80's should not throw the rear out but in my case after the lift that is exactly what it did.

It is my opinion that the oversteer should not have happened. Sure slop in steering can make it harder to recover but most drivers, even though they think they are internet Andretti drift kings, get behind the slide, overcorrect, and just make it worse. Ultimately, light understeer makes for a very controllable situation where one just needs to roll of a little speed to regain traction and recover.

To sum all of this up, I hope the couple cuts themselves some slack. The extra payload of the lift springs likely increased roll stiffness and make the truck more prone to oversteer. I hope those that desire to delete sway bars do so only to the rear unless they intend to consciously drive with oversteer in mind. I hope the rest of us go forth realizing that if we want stiff rear springs that don't sag under load, that we have to modify how we drive to account for the resulting oversteer tendencies.

If anyone wants to test their trucks slide tendencies, all you have to do is drive in a slowly tightening circle on a slippery surface (dirt...) at constant 25MPH (low speed) until it starts to slide. If the rear swings out, well, you know what to expect henceforth. You can use that trick to asses how changes to your setup impact your vehicle's slide tendencies.

Frank

 

[Rigidarm]

Godspeed your healing, new rig and many wonderful trips. Thanks for sharing.

 

[scrowley]

Damn! Glad you and family are ok.

 

[vipergrhd]

Glad to hear everyone is ok and the dogs are found, material things can be replaced and salvaged what you can if you plan on getting another 80.
Major goose bumps while reading the first part of your story specially when your GF blood curdling scream thinking she could be paralyzed from the neck down. Thank God you survive that ordeal and big kudos to Luke and the rest of the guys that helped out and for the vultures that stole your things Karma will come get you and you know it's coming. It's one thing if you found it on a trail but knowingly have seen a wrecked rig and taking advantage of the situation hope you Fawking thieves get what's coming to you.

 

[JohnnyFish]

<Non-80 related reply>
When I first started reading this thread I was thinking that the OP's trip is exactly what all people should put their relationship through if they intend to make it more permanent. I think Bill Murray famously gave a couple similar advice a few years ago. Reading the whole thing, I'd say that if you're still happily together, this relationship is good for the duration. Glad all three of you are okay. Sorry about the rig.
</>

 

[spressomon]

Hate thieves. Unscrupulous.

Looking at the collapsed A-Pillars & roof @ the first photo made me sick; but glad to know you only have mental scars to heal.

 

[grave]

Richie xepyt from LA fixed?

 

[Amacfly]

Lots of great info here on truck set suspension and steering set up, anyone got a good recommendation for a shop in LA area to go over all this and make sure that mine is as safely and sanely set up as possible?

 

[xepyt]

Richie xepyt from LA fixed?

Yep!

Lots of great info here on truck set suspension and steering set up, anyone got a good recommendation for a shop in LA area to go over all this and make sure that mine is as safely and sanely set up as possible?

RPM Garage in Monrovia, Steve will take care of ya