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Why does a rig roll?

Binder

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Seems to be much confusion on this subject so I thought I would start a discussion here......There are many variables why one rig would roll before another but probably the single biggest variable is center of gravity and where it is in relation to the lowermost point of a rig downhill- typically the outside edge of the tire where it would roll under.....Many people think that if a rig is wider it's automatically more stable but this isn't really true. If you think about it a typical wider rig is say for instance 86 inches wide and a narrower rig is say 76 inches wide. 10 inches difference seems like a mile but the difference is from the center of the rig or 5 inches. Still seems like a lot right?.....Now go off camber with the rig say 45 degrees now the difference is only 2-1/2 inches....Now take into account the height of the center of gravity of the two vehicles. The COG is a definite point which is difficult to measure but plays a huge role in this. For the purpose of this comparison say the narrower low COG rig were say 20 inches off the ground where the wider and high COG rig is 30 inches off the ground. That's 10 inches difference. Now lets take both of these rigs off camber.....
The 86 inch wide rig at 45 degrees the outside edge of the tire is only 21 1/2 inches from the center of the rig where the center of gravity is leaning 21 inches to the side. What does this mean? This rig is a hickup from rolling....
Now take the other rig. The 76 inch wide rig at 45 degrees the outside edge of the tire is only 19 inches from the center of the rig where the center of gravity is leaning 13 inches to the side. This rig has about 6 more inches before it will roll........
What I've tried to show here assuming my math is right:eeek: on a typical rig center of gravity has a much greater impact on how stable your rig is from rolling over than width.:;
:corn:
 
Well, it tis past 7...:haha:

Why does a rig roll?
Usually, because the driver is drunk, high, slightly mentally handicap'd, with 1 bad eye and the other has 20/60 vision, driving a 10 ft tall 70" wide, 85" wheelbase Jeep-like (seems to be the politically correct term) on 31" AT tires. Also, the cage is made out of old handicap shitter rail tubing with welds from a 1942 arc welder, and has a b pilar hoop. The seat belts are pieces of rope. But, its got a SBC 350 pushing 600 hp!:cheer:
 
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Now take momentum into account.

Or one rig crawling and another rig mashing the throttle.

Or one rig with stable suspension and another rig unloads and over it goes.

This is fun but the math part was confusing. :beer:
 
Now take momentum into account.

Or one rig crawling and another rig mashing the throttle.

Or one rig with stable suspension and another rig unloads and over it goes.

This is fun but the math part was confusing. :beer:

I did say there are many variables but I was using the physical properties of the rigs size itself as that seems to be the typical argument going...."a wider rig is more stable and safer":rolleyes:
 
I did say there are many variables but I was using the physical properties of the rigs size itself as that seems to be the typical argument going...."a wider rig is more stable and safer":rolleyes:


On a leaf sprung rig...yes,wider is better depending on how their Anti-wrap bar is built.

With links.......what is their AS %,is it nuetral or favor squat?
 
This is fun but the math part was confusing. :beer:

Yeah I know but it's hard to explain otherwise....Basically when the center of gravity goes out past the outermost point it will roll. What I've tried to show is that center of gravity will be a more important variable than width.......
More importantly if some drunk guy sitting behind a keyboard can show this then other people will figure this out too. If you persistantly keep making the "wider rigs are safer" argument then it makes you sound like you're crying wolf.:;
It just isn't true.
 
.......what is their AS %,is it nuetral or favor squat?

We haven't taken suspension into account on this yet as it's a width comparison....Given that AS doesn't matter when the rig rolls to the side. AS doesn't matter if the rig rolls front to back unless the driver is on the gas which brings up another whole set of variables....Remember anti squat is changing the height of the CG and changing the inertia of the vehicle at the same time....Our comparison had a given CG height.
 
We haven't taken suspension into account on this yet as it's a width comparison....Given that AS doesn't matter when the rig rolls to the side. AS doesn't matter if the rig rolls front to back unless the driver is on the gas which brings up another whole set of variables....Remember anti squat is changing the height of the CG and changing the inertia of the vehicle at the same time....Our comparison had a given CG height.

On off camber AS has everything to do with dumping the car to "the side". You are assuming "everyone" is in 4 dig when on the trail.

I don't care about your "comparison" parameters:flipoff:


Oh yeah........did you get your reverse fixed yet douche?.....****:rolleyes:
 
On off camber AS has everything to do with dumping the car to "the side". You are assuming "everyone" is in 4 dig when on the trail.

I don't care about your "comparison" parameters:flipoff:


Oh yeah........did you get your reverse fixed yet douche?.....****:rolleyes:

If the CG is fixed, it's fixed. If the suspension is moving around so is the CG...........
Not only did I not fix the trans but now the steering is jacked too.:rolleyes:
that's OK I can outwheel you with the superduty.
 
Yeah I know but it's hard to explain otherwise....Basically when the center of gravity goes out past the outermost point it will roll. What I've tried to show is that center of gravity will be a more important variable than width.......
More importantly if some drunk guy sitting behind a keyboard can show this then other people will figure this out too. If you persistantly keep making the "wider rigs are safer" argument then it makes you sound like you're crying wolf.:;
It just isn't true.

No I know, your first post made sense even to me. :beer:

And yeah I would agree with you width has less to do with a roll than COG height. But suspension characteristics and momentum (inertia?) also are bigger factors than width.
 
No I know, your first post made sense even to me. :beer:

And yeah I would agree with you width has less to do with a roll than COG height. But suspension characteristics and momentum (inertia?) also are bigger factors than width.

:awesomework:
 
When I put the yotas under the rig, I did noticed a marked improvement in stability...But I changed a few things...:;
Used to have massively tall perches on the light sami axles:redneck:, and longer shackles than I do now, with 2.5" backspaced wheels on 33's....I went to a shorter shackle and different, shorter perches, and a standard 3.75 backspaced wheel, coupled with the massively added weight of a toy axle (vs sami axle)....my total net gain in width was .5", but dropped the rig almost 1.5" in the process, while still getting 35's under it with no rubbing issues...have fit 36" TSL's under it, but with very slight rubbing, which the BFH took care of!!!:haha:
 
Why does a rig roll ?
1,Driver error
2, Mech. failure (my case):booo:
3, Pushing a rig to far (see #1)
4, Driving to fast. (see #3 and #1)
5, Drinking and wheeling. (see #1)
 

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