Roll over angle

[hobbsrt]

Hi, can anyone help me figure out my roll over angle? I just finished building a 2001 GMC 2500 crew cab long bed. Its got a 2" life with 37" tires, a custome aluminum flatbed and a 4 wheel camper Grandby model on top of that. I am hoping to be able to determine the roll over angle to avoid rolling it over. Any help would be great. Thanks.

 

[Explorerinil]

I’m not sure on how you would figure that. Im sure there’s a way to get a general idea, but many factors can change it, tire pressure, loose or muddy ground, rocky ground, etc.

 

[Explorerinil]

one time I about rolled my 01 dodge on a trail back in the day, the truck was rocking side to side, it was not a good feeling. At the badlands off-road park years ago on an off camber trail I saw a Jeep roll over as he lost a bead on one of his tires.

 

[Wilbah]

I'm with everyone here....you could in theory calculate it in your driveway but then when you're on a trail at speed (even slow) with different loads, different camber, different traction it would all change. Just too difficult to predict with any certainty imo. I 100% get why you want to know, just it may be one of those things better just always being safe than sorry- no matter what angle you come up with there will be a time when it will roll at 5 (or some amount) degrees less and if you were using the number as a guide it would get you in trouble.

 

[PIC4GOD]

Listen to your pucker factor. I've been on many trails where my pucker factor kicked in way before I was in danger of tipping. If you don't have that sixth sense than I would keep it to tame forest service roads. Where do you plan on taking such a big vehicle that causes you concern?

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[73Carlow]

The toughest thing you are up against is the weight of that topper/ camper. that can shift the weight pretty rapidly. Ultimately the slow and steady will likely get you through most anything you come up against with such a mild lift.

 

[BritKLR]

Seat of the Pants Meter. I think they sell em on e-bay.....I know what you mean, it really just is time, terrain and truck experience. I have a pretty good sense about my truck but even this slight lean left me sweating and getting out and walking the trail. One simple tire drop and the rear suspension unloading could have caused it to go over.

 

[Desert Dan]

Vintage Land Rover Operating Angle Testing


https://assets.bwbx.io/images/users/iqjWHBFdfxIU/iaF994inKu9c/v1/1200x-1.jpg

 

[JWayneGreen]

An expensive question/answer to be sure. Have a similar setup to yours, and had my hair on end a few times last year in UT. If you figure this out, your ahead of many people I have seen out on trails. I stop when I start holding my breath.

 

[Explorerinil]

I saw a gauge that’s let’s you know what angle your at, I guess you could get one of those.

 

[ttengineer]

A static roll over angle would be greater than a dynamic one. Unless you’re hauling butt and centrifugal force is counter acting gravity.

In general if you’re in a truck with a flat bed and camper, I would avoid anything greater than a 40% cross slope or around 20deg. And honestly probably closer to 25% or 14ish degrees is safe. Pucker factor would start hitting around around 10-15deg. 20 deg would feel like you’ll tip over any sec.


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[hobbsrt]

thanks everyone. I was just looking for a guideline. I agree pucker factor is the best gauge but would like to know limits. If it's 15 degrees I wouldn't want to push that just thought it would be good to know. I am not sure where the truck will bring me. I am not looking to go rock crawling or do anything crazy, but want to be able to tackle some medium trails to get to good camping spots.

 

[PJorgen]

Yes, you can calculate the theoretical critical roll over angle, but it's a PITA and not very useful in practice.

First you need to calculate the height of the center of mass (gravity) for your vehicle. Here's a short article from Car and Driver describing how to do that: https://www.caranddriver.com/news/a18201745/explained-how-to-measure-center-of-gravity-height/

Then you draw a right triangle with the center of mass height as the side of the triangle, and one-half the width of your vehicle, measured between the mid-line of the tires as the base of the triangle. Use trigonometry to calculate the adjacent angle and that is your critical roll over angle. Simple right?

Couple of limitations to this (actually many limitations but I'll just mention two).
First, the calculation assumes the center of mass is exactly centered left to right. If not, the roll over angle will be different depending on which side of your truck is the high side.
Second, as mentioned above, this is a static angle. If you're driving on a side-slope and hit a rock, the rebound on your suspension and/or tires can easily push you past the critical angle.

Have fun, let us know what angle you come up with.

 

[Mundo4x4Casa]

You have more tilt available than you think, especially with all the heaviness near the bottom; a pop up; heavy drivetrain. I've been to the edge, and sometimes over the edge:









Sometimes the lean was too far causing this: 20 years ago I dislocated my shoulder here on the Little Sluice when I came over hard. It was so bad that i now have a titanium total reverse shoulder replacement:

another too far:




jefe

 

[ExplorerTom]

A tilt table and a rope (to keep you from flipping)