Rollover angle

[delloro]

I have been wondering about this subject, and this thread inspires me to ask: what is the max angle, front-to-back and side-to-side, that a 4runner can safely traverse?

Anybody here flipped or rolled a vehicle off-road?

 

[LawnDart]

I have been wondering about this subject, and this thread inspires me to ask: what is the max angle, front-to-back and side-to-side, that a 4runner can safely traverse?

Anybody here flipped or rolled a vehicle off-road?

Tons and tons of a factors contribute, so it's hard to say "X+Y=Z" as much as we want to do so.

I've been in a HMMWV that rolled while filming, and it was at 30mph off a small ditch, but it hit the right angle to create enough leverage.

I'd be interested to know what the stock MAX angle is for a bone stock 4runner is, however that all changes when we add extra gack, people, cargo.

 

[1engineer]

I have been wondering about this subject, and this thread inspires me to ask: what is the max angle, front-to-back and side-to-side, that a 4runner can safely traverse?

Anybody here flipped or rolled a vehicle off-road?

1. Are you moving?
2. Have you aired down?
3. Are you lifted?
4. Do you have passengers?
5. Do you have a loaded roof rack?
6. Are you on dirt or pavement?
7. Are you on an incline already?
8. Do you have a different suspension?
9. Are you running bigger tires?
10. Are you running aftermarket skids?


I ask because all this matters. In reality, if you were traversing across a side hill most would either panic or stop before the angle got too great and a roll over happened. It's a lot more than you would think.
Now, if your vehicle is moving, you can flip it at a low speed. Here is a link to a thread I did a year or so ago on tripped rollovers. http://www.toyota-4runner.org/5th-gen-t4rs/183943-young-engineers-using-5th-gen-4runners.html

 

[DesertCanyons]

Tilt angle

Hi Dellero,

I've seen sway gauges in 4Runners that show you your angle of tilt with a bubble in a curved tube. Sorry, I don't know the correct name of this gadget. But if you want to get a sense of the angle when you feel you're at risk of roll-over then install one of these simple levels on your dash and keep an eye on it.

I think LawnDart is right. It depends on many factors, some of which vary with load, height of load (center of gravity) etc.

 

[LawnDart]

Keeping your COG low is important, keep less stuff off your roof and make sure your load is secured. I've seen vehicles tip at 25 degrees because everything not tied down suddenly went from one side to the other.

So much factors into it. I've gone as far as 45-50 degrees in mine, using my iphone as an inclinometer, and I know I puckered, and I've also some people go even further but in lighter rigs. Not all terrain is the same, not all vehicles are the same. I don't think there's any rule that says "If you are a 4runner you will be totally fine at X angle"

 

[jwkilgore]

All good answers so far, but assuming you're talking about a stock 4Runner, the biggest factors would be load distribution (passengers, cargo) along with speed, direction, and surface type.

You may be safe on a smooth side slope creeping along, but tip over on the same slope in the same direction if your uphill tires hit a 3" rock or downhill tires drop into a little hole with a little speed.

All that said, I'll agree with others in that if you are driving slow without large holes/rocks to throw momentum around, 95% of drivers will panic and stop long before they get to the tipping point. I.e., it will handle a smooth slope much steeper than you think is possible. If off-roading with my wife, she'll be freaking out on slopes that I know from experience are a long way from the tipping point.

 

[LawnDart]

All good answers so far, but assuming you're talking about a stock 4Runner, the biggest factors would be load distribution (passengers, cargo) along with speed, direction, and surface type.

You may be safe on a smooth side slope creeping along, but tip over on the same slope in the same direction if your uphill tires hit a 3" rock at 30mph.

All that said, I'll agree with others in that if you are driving slow without large holes/rocks to throw momentum around, 95% of drivers will panic and stop long before they get to the tipping point. I.e., it will handle a smooth slope much steeper than you think is possible.

One good point, if you're in the dunes and carving in sand bowls you can get vehicles to just absurd angles, like 75+ if you have the speed and attack angle correctly. In thrust we trust. But offroad at 1-2mph creeping along you don't have that on your side.

 

[A.Wilson013]

I've been in more vehicles rollovers than I care to admit (f you, M-ATV).

In my experience the terrain had more to do with it than the vehicle, really. You see an off-camber area and think, "oh, that's easy" and then you get half way through and your downhill tires sink, and there you are, sitting sideways with every G.D. thing you forgot to secure falling on your face. Not that any of that matters to you.


FWIW-
My little tilt gauge in my 1st gen told me not to exceed 35 degrees.

 

[sf jakey]

Keeping your COG low is important, keep less stuff off your roof and make sure your load is secured. I've seen vehicles tip at 25 degrees because everything not tied down suddenly went from one side to the other.

So much factors into it. I've gone as far as 45-50 degrees in mine, using my iphone as an inclinometer, and I know I puckered, and I've also some people go even further but in lighter rigs. Not all terrain is the same, not all vehicles are the same. I don't think there's any rule that says "If you are a 4runner you will be totally fine at X angle"

You have never driven a 50 degree slope. It is physically impossible, unless you consider driving off a cliff. You mean 50% grade?
https://en.m.wikipedia.org/wiki/Grade_(slope)

 

[1engineer]

One good point, if you're in the dunes and carving in sand bowls you can get vehicles to just absurd angles, like 75+ if you have the speed and attack angle correctly. In thrust we trust. But offroad at 1-2mph creeping along you don't have that on your side.

"Momentum is your friend" is the mantra we repeat when riding singletrack.

 

[1engineer]

You have never driven a 50 degree slope. It is physically impossible, unless you consider driving off a cliff. You mean 50% grade?
https://en.m.wikipedia.org/wiki/Grade_(slope)

Dude. Even I have ridden my bike across steeper slopes.The track at Bristol is 36 degrees and it could go much higher depending on velocity.

As far as vehicles, here's a pic. Remember momentum is your friend.

 

[blacksheep4]

You have never driven a 50 degree slope. It is physically impossible, unless you consider driving off a cliff. You mean 50% grade?
https://en.m.wikipedia.org/wiki/Grade_(slope)

I don't think he was referring to slope or grade but the tilt angle of his truck... you don't have to be driving on a vertical wall to get your tilt angle that high.

 

[LawnDart]

I don't think he was referring to slope or grade but the tilt angle of his truck... you don't have to be driving on a vertical wall to get your tilt angle that high.

This. The vehicle doesn't sit on the same angle as the slope, and is inclined to start tilting further inwards towards the point of tipping. Hence why you CAN roll over on a moderate grade given the right speed, and center of gravity. Shit, you can tip over at 10 degrees if you're an idiot.

So back to the original ask, that's why pegging down a universal roll over point is near impossible. There's points where I felt watching other vehicles I thought they'd for sure roll, and didn't.

The Land Rover Discos are amazing in this regard, because they look so top heavy, but so much of the weight is lower, and that shit is devil magic when they look like they've damn near got a "wallhack" code going in real life.

 

[Midnight Anvil]

1. Are you moving?
2. Have you aired down?
3. Are you lifted?
4. Do you have passengers?
5. Do you have a loaded roof rack?
6. Are you on dirt or pavement?
7. Are you on an incline already?
8. Do you have a different suspension?
9. Are you running bigger tires?
10. Are you running aftermarket skids?


I ask because all this matters. In reality, if you were traversing across a side hill most would either panic or stop before the angle got too great and a roll over happened. It's a lot more than you would think.
Now, if your vehicle is moving, you can flip it at a low speed. Here is a link to a thread I did a year or so ago on tripped rollovers. http://www.toyota-4runner.org/5th-gen-t4rs/183943-young-engineers-using-5th-gen-4runners.html

So basically where is your center of gravity, how fast is it moving, and in which direction relative to intended direction of travel? Right? (Not being sarcastic)

 

[Antman]

1. Are you moving?
2. Have you aired down?
3. Are you lifted?
4. Do you have passengers?
5. Do you have a loaded roof rack?
6. Are you on dirt or pavement?
7. Are you on an incline already?
8. Do you have a different suspension?
9. Are you running bigger tires?
10. Are you running aftermarket skids?


I ask because all this matters. In reality, if you were traversing across a side hill most would either panic or stop before the angle got too great and a roll over happened. It's a lot more than you would think.
Now, if your vehicle is moving, you can flip it at a low speed. Here is a link to a thread I did a year or so ago on tripped rollovers. http://www.toyota-4runner.org/5th-gen-t4rs/183943-young-engineers-using-5th-gen-4runners.html

^^^^Love this guy.

 

[2014 Warthog]

The main thing is to try to maintain a balanced and low load as much as possible. But one thing to keep in mind that if wheeling alone, there is you, the gas tank and the battery all on the same side of the vehicle (depending on model newer ones mostly).

It's why I keep my high lift on the passenger side of the rack, mounted my fridge on the pass side and keep my heavier recovery gear in the footwell of the rear pass seat. (Though as I think about it, I should devise a way to keep those bags in place in case of a roll over, getting hit by one would suck)

 

[jwkilgore]

You have never driven a 50 degree slope. It is physically impossible, unless you consider driving off a cliff. You mean 50% grade?
https://en.m.wikipedia.org/wiki/Grade_(slope)

50° does seem high, but several references I've found state that the 4Runner and Prado are "engineered for 42° side slopes". I've found several published references for 4x4's capable of 45° (http://www.mitsubishi-motors.com/en/showroom/l200/performance/). Throwing in safety factors and Toyota's conservative nature means you should be able to easily exceed that in certain conditions. A 4Runner with several hundred pounds of low-mounted armor (bumpers, skids, slides), with spacers to widen the stance, without a lift and without a heavy rack... 50° may just be possible. I personally wouldn't be willing to give it a try, but maybe someone has. The biggest danger in this situation would be if you started to slip sideways but then your wheels catch and momentum keeps you going over.

That said, people do tend to over-estimate slopes without an actual inclinometer measurement, especially if they are inside a vehicle at the time. The steepest standard modern side slopes for roads cut into earth banks is 2:1 (2-ft horizontal for every 1-ft vertical... 50% grade), which is about 26.6°, but most people would estimate it at 45°. Very few non-offroaders would even think about crossing a 2:1 slope sideways, even though it's well within the capabilities of almost any decent full-size 4x4 vehicle (again, assuming you don't have 4" lift with a RTT, spare tire, and 20-gal of fuel mounted on a rack).

Most road side slopes are a much shallower 3:1 (18.4°, 33% grade), which is right at or even above the max comfort level of most people. Highway engineers consider a 3:1 down-slope to be traversable but non-recoverable. Almost any highway passenger vehicle can safely drive it slowly, but if you go off the road in an accident you won't be able to turn back uphill at speed.

 

[LawnDart]

The main thing is to try to maintain a balanced and low load as much as possible. But one thing to keep in mind that if wheeling alone, there is you, the gas tank and the battery all on the same side of the vehicle (depending on model newer ones mostly).

It's why I keep my high lift on the passenger side of the rack, mounted my fridge on the pass side and keep my heavier recovery gear in the footwell of the rear pass seat. (Though as I think about it, I should devise a way to keep those bags in place in case of a roll over, getting hit by one would suck)

That's a really really good point.

I had a fairly brutal experience at Hollister Hills when I was in CA around July, and wound up on one of the black diamond trails, and narrowly avoided putting the car into a tree or on its side.

It made me consider relocating a lot of weight further south, so that helped me decide on the CBI bumper, in that I carry extra fuel and my high-lift on the bumper, which has helped. But the thing that Warthog brings up is cargo load, and securing that load.

I keep all my recovery gear in hardcases in the rear right of the cargo area, strapped down so they can't slide hard left if I'm off camber. I need to improve this security more because it could be disastrous if it slides left. Un-secured loads are scary as shit in any moving vehicle.

But the big thing that he brings up is distribution of loads. If at all possible don't put gear on the roof. A roof rack is great for soft goods and other things, but raises your CoG. And the 4Runner is heavily weighted to the left side of the vehicle (hence the 4Runner 'lean'. So keep that in mind when you put a fridge or gear in the back). I've noticed off camber if I have most of my weight on the front left and rear right, that the vehicle can teeter easily when the front right or rear left loses contact. So placing gear evenly is a big lesson to take into account.

 

[sf jakey]

Dude. Even I have ridden my bike across steeper slopes.The track at Bristol is 36 degrees and it could go much higher depending on velocity.

As far as vehicles, here's a pic. Remember momentum is your friend.

Ive ridden bikes and motorcycles on some very steep slopes. Ive skied slopes approaching 60degrees. Im sure a trick driver on a course or designed obstacle can make a vehicle stick in situations such as your photo. A stock or modified 4runner is not traversing a 50 degree slope or anything even approaching that in ordinary circumstances.

 

[JWaldz]

I'll climb hills and crawl over literal boulders all day long, it's the leaning off camber stuff that gives me the heebie jeebies.

There are A LOT of factors. I've been in more situations than I care to admit to that should have ended badly. Add in other factors and it may have been better or worse in the situation.

I know I don't have a 5th gen so I can't honestly give the numbers, stats, etc.. you're looking for, but when it comes to the tipping point there isn't just one factor that says, hey lets go ahead and tip this bad boy over. There's multiple factors.

Low COG and keeping even weight as close the ground as possible will help when it comes to tipping. However, if you're climbing up a boulder in a mall parking lot too fast and not paying attention, there's no hope for you.

If you've been wheeling the same truck for years, like I have, you get to know what your truck is capable of. Don't get too comfortable though, as changing suspension and such will change the capability of your vehicle. Get to know your rig before you go climb Mt. Everest with it.