The tipping point

[simonsnork]

Hello again,

We are now up in eastern Oregon roaming the high desert before I have to go back to work. As we drove down a beautiful rolling dirt road by Diamond Craters today, the road began to get a little side hilled. Now to give you some information about myself, I drove and lived in an old 404.1 for about eight years in my twenties. I have lumbered about and 4x4rd plenty. And I know what it is like to be a little sideways. Granted the unimog was so forgiving that I could do just about anything I tried, even if I had no idea what I was doing. But the thing never flipped. Don't worry neither has the fuso. But as we listed over and I watched the tilt meter go a little past 15 degrees my stomach started to tighten. I didn't think we were going to roll but I did wonder, how far is too far?
So my question to all of you with more time behind the three red diamonds than I is, how far will you take it? For that matter, does anyone have a good way to figure out the tipping point of their rig without putting it on it's side?

I have another thread I'm about to start asking about divorced overdrives in a fuso. So if this is to banal and pedestrian a topic, please hop over to my next one and chime in.

Thanks as always.

Simon

 

[Aussie Iron]

I'll chime in here as well. Another nice pic.
I operate bulldozers regularly in steep country so I know what steep side slopes are, where you are hanging onto the seat by your ar***ole. My Canter has been very close to that because I had the same effect on the Canter seat. Now there are a lot of factures involved in how your Canter is balanced - weight up high or down low in your camper. But yes they can handle quite steep side slopes.

Dan.

 

[Chorky]

While I dont have a rig like yours, it is a thought I had myself many times for my Jeep and F350. A few years ago went testing the new truck suspension, and decided to turn around at the bottom of a steep loos gravel jeep trail with lots of undulating and deep ruts. It was probably 15-20 deg, and certainly made me nervous!! I think as Dan mentioned it is highly variable based on your load alone. I'm not an engineer, but I think if you were to consider a 100# weight in center, on the frame, and then move it up 4', there would be some sort of exponential decrease in side slope ability.

In any case, the only way I know people have tested rollover points is by tying straps on the lifted side to a dozer or something that won't move, and lifting that same side with a forklift. Then at whatever point rollover happens, your safe max zone would be 5 degrees less to hopefully account for bumps and dips in the road. I'm not sure how accurate and true this is, but it is the only method short of extensive engineering that I have seen people use. It seems to work, if nothing else gives you a baseline rollover number to use in absolute best case situations.

 

[gait]

I wouldn't enjoy that either.

The Mitsubishi has a narrow chassis (to accommodate the dual rear wheels). Very different to the unimog. It feels different.

Roll will depend on weight and centre of gravity and springs and tyre pressures and

Things improved for me when I reduced the weight of solar panels on my roof by about 80kg.

This may give you some confidence ..... double decker bus tips at 28 degrees
.... though I think I chicken out before the Canter does.

 

[javajoe79]

While I dont have a rig like yours, it is a thought I had myself many times for my Jeep and F350. A few years ago went testing the new truck suspension, and decided to turn around at the bottom of a steep loos gravel jeep trail with lots of undulating and deep ruts. It was probably 15-20 deg, and certainly made me nervous!! I think as Dan mentioned it is highly variable based on your load alone. I'm not an engineer, but I think if you were to consider a 100# weight in center, on the frame, and then move it up 4', there would be some sort of exponential decrease in side slope ability.

In any case, the only way I know people have tested rollover points is by tying straps on the lifted side to a dozer or something that won't move, and lifting that same side with a forklift. Then at whatever point rollover happens, your safe max zone would be 5 degrees less to hopefully account for bumps and dips in the road. I'm not sure how accurate and true this is, but it is the only method short of extensive engineering that I have seen people use. It seems to work, if nothing else gives you a baseline rollover number to use in absolute best case situations.

This is what I am planning on doing once my build is complete.

 

[biggoolies]

BEV CG Calculation

www.hackneys.com

 

[simonsnork]

Ok, I think I understand. Scrap the Fuso and get an old London double decker to drive around in if I plan on side hilling.
Done!
I'm in

I was thinking of the strap test system myself. Lucky for me there is almost no weight up high in our fuso.
It still feels creepy.

Thanks to all.

Simon

 

[Buckstopper]

A lesson we learned from the Camel Trophy Guys at Overland Expo was to watch the sidewall on the uphill tires. When they start to loose the bulge you might want to turn downhill real soon. Having a spotter helps. I have been impressed at how stable the Fuso is.

Buckstoppper

 

[Aussie Iron]

A lesson we learned from the Camel Trophy Guys at Overland Expo was to watch the sidewall on the uphill tires. When they start to loose the bulge you might want to turn downhill real soon. Having a spotter helps. I have been impressed at how stable the Fuso is.

Buckstoppper

Actually that makes a lot of sense because the weight is coming of the top tyres just before rollover.
Need to remember that.

Dan.

 

[Chorky]

yes but that would only work if you had someone paying attention to the tires....

 

[rruff]

I didn't think we were going to roll but I did wonder, how far is too far?

Thanks as always.View attachment 504522

If you draw a vertical line through the low tires, you need as much mass*lever arm on the right side (looking at the photo) than the left. It's obvious that you aren't close. Maybe half way?

It's important to note that this is only when at rest. If you suddenly hit a pothole on the down side, or the road gives way, or you veer suddenly, the angular momentum could put you past the tipping point if you are close to start with.

 

[PKDreamers]

I will put that under M for memory , great idea.

 

[pugslyyy]

It will go a lot further than you think it will without tipping...

 

[Curtis in Texas]

Changing the subject a little. You mentioned a divorced overdrive. Are you thinking Gear Vendor style or Spicer 5831 Over/ Under divorced gear box? Is your transfer case divorced? I have a Spicer I am hoping someday to use with an overland rig, provided I can find a 4WD truck with a divorced "T" case. Or build a 2WD truck with 2 divorced gear boxes and add a front drive axle.

Anyway, the Spicer 5831 I have has a .74 OD- 3rd gear, a 1:1 second gear and a 2:1 under drive 1st gear. These things are rare and a little on the pricey side for a good used one I'm told. Had mine rebuilt when I bought it, thankfully.

So my question is more about what gearbox set up you have than trying to sell my gearbox. Hoping my plan is still do able. Been planning and gathering parts for a new rig since 2001.

But I thinking I may base mine on an Isuzu FR. Mainly because I'll be down sizing from a 40 foot Class A Coach. Wife likes her space. But I like the boonies.

 

[gait]

yup, further than we think, there was a rice paddy below the truck