Bilstein 5100 review & Gobi rack in 3 weeks
- Thread starter gago1101
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Titanpat57
Senior Member
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gago1101
New member
Just to clarify this, especially for you since it appears you are an engineer.
1) 70 lbs on the roof is not the same as 150 lbs in the passenger compartment. And 150lbs in the passenger compartment + 70 lbs on the roof is way worse.
2) I went back and did some calculations of my own.
2010 4runner has a shitty rollover rating (static stability factor = 1.12)
http://www.motortrend.com/cars/2010/toyota/4runner/crash_test_ratings/
2010 Toyota 4Runner Crash Tests, Results, & Safety Ratings at Autobuyguide.com
Toyota 4Runner 4-DR. w/SAB Car Safety Ratings
Now based on this number, one can get the 4runner's center of gravity figure, witch is 0.7165 meters with the conversions and a known equation.
Rollover Prevention Docket No. NHTSA-2000-6859 RIN 2127-AC64
Changes in center of gravity is an important value in cargo shipping, so equations to calculate the shifts are readily available. Here is one link with descriptions.
http://thenauticalsite.com/Nautical...bility-Lesson04-MovementOfCentreOfGravity.htm
Now look at vertical weight additions and removals section. Plug in the numbers for our 4runner remembering that our CG (center of gravity) is 0.7165 meters to start with. With base weight of 4750lbs (2154 x10^6 grams) and the final weight of adding 70 lbs, 4830 (2191 x10^6 grams). Do the calculation and you get a final CG (center of gravity) of 0.73976 meters. Now the increase in CG does not sound much, but please place it back to the static stability factor (SSF) calculation equation and you get SSF of 1.084 down from 1.12
That right there put the 4runner with the Gobi rack at the 2-star rollover rating instead of 3 star.
You can find lost of information about the SSF and rollover probability going back decades. SSF drop of 0.04 is significant. The load limitation of 300lbs on the roof is for the same exact reason, loss in handling capabilities, not the weight itself on the roof- correct me if I am wrong on this.
Hope with helps. .. And I do not have beef with anyone, just do not insult me!
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gago1101
New member
You are correct and that was the reason I took that number out. Still, an inch increase in CG is huge when talking handling. ..and it does not change the static stability factor of 1.084, drop from 1.12
Viper45
New member
For fear of sounding ignorant and condescending at the same time, please don't take it as such...
But if you knew that lifting your vehicle (even by so much as 1 in) was going to adversely effect the handling/CG/rollover characteristics, why bother adding the lift in the first place?
But if you knew that lifting your vehicle (even by so much as 1 in) was going to adversely effect the handling/CG/rollover characteristics, why bother adding the lift in the first place?
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gago1101
New member
Dear Viper,
the question here is about adding the Gobi rack on top of a stock 4runner. Adding the lift will make it worse. Now I knew it was going to affect the handling adversely, and I still went ahead with the lift and the rack, and I would do it again. If your read my initial post, I was just reporting my findings after the install, no regrets- I love the lift and the rack. I have not tracked this car or plan to in the future. This is my Armageddon vehicle, if you know what I mean, LOL
Titanpat57
Senior Member
I have to ask...
what is rating on the new tires you put on?
what is rating on the new tires you put on?
gago1101
New member
113S, same as the original Dunlop Grandrek. The softening noticed with more weight is likely related to these soft tires, but the overall lean, unlikely.
Titanpat57
Senior Member
I don't doubt what you say if in fact you still have the P rated tires on...that was the way mine felt (pre-gobi) but the new E rated tires got rid of that "driving on a ball" feeling. The Airlift 1000 bags also helped improve the handling...and thats a super cheap mod.
anda:
gago1101
New member
I am sure I will feel a difference going to the stiffer tires. Not ready yet to spend anther $800 though. I am thinking of 285s in the future and may consider E rated tires.
OBW2011
New member
gago1101, Welcome to the forum, your rig looks great!
As I'm sure you know it takes a little time to get used to a new vehicle and its handling dynamics, especially one that has been altered with aftermarket parts (lift, rack, etc.). My advise is to learn and know how your vehicle handles as well as your own driving abilities and drive within both. Not doing so is what would make your rig dangerous or not. The lift and rack are just things to take into consideration when learning or knowing your capabilities.
That's my 2 cents take it for what it's worth. :nicethread:
P.S. What wheels are you running?
As I'm sure you know it takes a little time to get used to a new vehicle and its handling dynamics, especially one that has been altered with aftermarket parts (lift, rack, etc.). My advise is to learn and know how your vehicle handles as well as your own driving abilities and drive within both. Not doing so is what would make your rig dangerous or not. The lift and rack are just things to take into consideration when learning or knowing your capabilities.
That's my 2 cents take it for what it's worth. :nicethread:
P.S. What wheels are you running?
gago1101
New member
I agree with you fully. A lot of it is a compromise. We buy the car and put the rack on top for a purpose. Similarly, I accept the fact that my Porsche is not an offraod rock crawler, and certainly it doesn't mean that it is a bad car or I should be upset about it.
MB TKO (17x8.5 -6mm offset) wheels from discounttiredirect.com, they are only $120
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1engineer
Moderator
Just to clarify this, especially for you since it appears you are an engineer.
1) 70 lbs on the roof is not the same as 150 lbs in the passenger compartment. And 150lbs in the passenger compartment + 70 lbs on the roof is way worse.
2) I went back and did some calculations of my own.
2010 4runner has a shitty rollover rating (static stability factor = 1.12)
2010 Toyota 4Runner Safety & Crash Test Ratings - Motor Trend Magazine
2010 Toyota 4Runner Crash Tests, Results, & Safety Ratings at Autobuyguide.com
Toyota 4Runner 4-DR. w/SAB Car Safety Ratings
Now based on this number, one can get the 4runner's center of gravity figure, witch is 0.7165 meters with the conversions and a known equation.
Rollover Prevention Docket No. NHTSA-2000-6859 RIN 2127-AC64
Changes in center of gravity is an important value in cargo shipping, so equations to calculate the shifts are readily available. Here is one link with descriptions.
http://thenauticalsite.com/Nautical...bility-Lesson04-MovementOfCentreOfGravity.htm
Now look at vertical weight additions and removals section. Plug in the numbers for our 4runner remembering that our CG (center of gravity) is 0.7165 meters to start with. With base weight of 4750lbs (2154 x10^6 grams) and the final weight of adding 70 lbs, 4830 (2191 x10^6 grams). Do the calculation and you get a final CG (center of gravity) of 0.73976 meters. Now the increase in CG does not sound much, but please place it back to the static stability factor (SSF) calculation equation and you get SSF of 1.084 down from 1.12
That right there put the 4runner with the Gobi rack at the 2-star rollover rating instead of 3 star.
You can find lost of information about the SSF and rollover probability going back decades. SSF drop of 0.04 is significant. The load limitation of 300lbs on the roof is for the same exact reason, loss in handling capabilities, not the weight itself on the roof- correct me if I am wrong on this.
Hope with helps. .. And I do not have beef with anyone, just do not insult me!
First off, thank you for actually doing some research before blindly replying to me with some witty comment that meant absolutely nothing. Your above post, unlike your original post below, shows that you actually wanted to present some type of factual evidence to back you up instead of dire unsubstantiated claims that it is dangerous to mount a rack to a stock TE as you did below. You have to remember that you are posting in an enthusiast's forum that has many smart (and some looking to get smarter) people here. Some of these guys are amazing with what they have accomplished! Your above post did well to inform those who are curious about such things as "CG' and rollover.
Now, you used the SSF, or Static Stability Factor, as your basis to reinforce your original claim. Good for you! This number is a comparative number for general consumer reference. Never mind that anyone with an IQ above 68 can generally figure out that high and narrow will tip over before short and wide. Our government decided that we needed a number for those people who can't figure that out.
The SSF is a good place to start, but unfortunately it has drawbacks. I told you that I did some quick calculations after your first post and came up with almost negligible results. BTW I said "You, your wife and some luggage" not "150 lbs" unless you both are rail thin and only brought a toothbrush.
The SSF does NOT take into account the actual difference in models, modifications or suspension and tires. They choose the biggest volume seller and in this case it is the SR5. They will lump the LE and TE into that same SSF even though they have different suspension controls. They do change for major changes like going from 4th gen to 5th gen but again, do not differentiate models. Also they do not include any vehicle stability controls. To say in a static condition you can tip something over is one thing. To tip it over in a dynamic condition with ABS, VSC and yaw controls actively managing the vehicle is something else entirely. There are many other drawbacks to the SSF but I agree it is a good public consumption number assuming everything else on every vehicle is equal such as tires and suspension. If you really want to calculate it correctly use this http://www.eng.auburn.edu/~dmbevly/gavlab/pub-pre/A Study of Rollover Propensity.pdf as a guideline.
Even after you calculated the "new" SSF for your 4Runner it still falls into the same general range as most SUV's and older 4Runners here http://www-nrd.nhtsa.dot.gov/Pubs/809868.pdf in this document.
For additional reading on how vehicle stability control will make a mockery out of the SSF number read this SUV Rollover in Single Vehicle Crashes and the Influence of ESC and SSF article.
And last but not least, the SSF is only one metric. As important as this number is it is also just as important in determining a rollover risk with your vehicle if you are:
Male or female
Under or over the age of 25
Have been drinking
as evidenced here again in table 3. SUV Rollover in Single Vehicle Crashes and the Influence of ESC and SSF
So if you are a female under the age of 25 that has been drinking while driving an SUV, you are SOL!
Now, to address the below original post:
Most everyone here knows if you lift it and put some weight on top it will not handle as good as if you dropped it and put some low profile tires on it. You don't need anything but common sense to tell you that. Now, if you did some extensive suspension modifications to it I'm sure you could make it handle better than stock, such as Icon stage 6 or something.
Again, I appreciate you posting the conclusions to your research. Your truck looks nice. I would suggest some better tires that will hopefully negate any feelings of fear in the future when you drive it.
1engineer
Moderator
Had a pm question from one of the members relating to the above post so I thought I would bring it back up again. The answer is in this link http://www.eng.auburn.edu/~dmbevly/gavlab/pub-pre/A Study of Rollover Propensity.pdf to your question, and I answered in in a pm too.
