k5 rollover statistics

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by loudnowlouder, Dec 6, 2001.

1. loudnowlouder1/2 ton status

Joined:
Jan 29, 2001
Posts:
539
0
Location:
Ellicott City, MD
as a final paper for my graduate vehicle dynamics class i chose of course the rollover of suvs....i dealt with single vehicle accidents and came up with some percentages of how likely you are to roll over during a quick evasive maneuver....(percentages were found by using the Static Stability Factor which relates the track width of the vehicle and the height of the center of gravity and then compared with actual crash data accumulated by NHTSA)

an average passenger car has a 10-15% chance of rollover, where an average SUV has a 30% chance of rollover...
a stock K5 has a 34-35% chance of rollover, and the numbers skyrocket when lifts and big tires are added....
by raising your center of gravity by 4 inches, the chance of rollover is 55%, 6 inches gives a 70% chance of rollover, and 8 inches gives near a 90% chance of rollover.

so my dads advise long ago was correct, just hit the deer, at least you'll be able to drive home.

2. Triaged1/2 ton status

Joined:
Feb 21, 2001
Posts:
3,808
0
Location:
CA (LA/OC area)
It is nice to see you did your "homework" on that. I am also a ME student and would like to go into automotive eng. One of my projects was/is the Formula SAE design comp. I have learned alot. I am starting on the design now for our 2003 car. You can see pics of the 2000 car See it Here

3. loudnowlouder1/2 ton status

Joined:
Jan 29, 2001
Posts:
539
0
Location:
Ellicott City, MD
yeah we have a formula sae car here too, it was made in the early 90s, we just use it for vehicle dynamics testing, we set up an autocross course and test for x acceleration, y acceleration, yaw rate, steering wheel angle, side slip angle, to ultimately plot a G-G diagram...

<a target="_blank" href=http://www.futuretruck.umd.edu/>Futuretruck</a> is the homepage for the hybrid project...the burban was just retired, and a 2002 ford exploder was delivered....the webpage isnt great...we spend too much time messing with the trucks...

4. Pure Insanity1/2 ton status

Joined:
Mar 17, 2001
Posts:
4,579
0
Location:
8" gives a 90% chance! I better watch out, mine may fall over in the driveway!

If ya can't stop.......Smile as you go under!
PIC of mine from flblazers site<a target="_blank" href=http://www.flblazer.alloffroad.com/photo3.html>
GO</a>

5. TorkDSR1/2 ton status

Joined:
Sep 1, 2001
Posts:
1,258
0
Location:
bucks co pa
i dont understand what that percentage represents.?? are you saying that 90% of all k5s lifted 8'' will roll over?? if so im glad i got a k15.

or is that in an accident? and did the NHTSA really test lifted rigs? what a waste of a vehicle "here billy, put this brand new Rancho lift set on this truck, cause we're gonna crash it"

i wanna drive the crash truck, it'd be like ridin with Shaggy K5

Tork DSR
"look ma, i can make the dog pee white...."
aol screen name TorkDSR

6. muddin4fun3/4 ton status

Joined:
Feb 19, 2001
Posts:
5,644
0
Location:
N Texas
He said during a quick evasive manuver. Like, an old lady runs out in front of you while you're going down the highway and you swerve.

Don't hit me, Mr. Moderator... I'll go back on topic... I swear!

<a target="_blank" href=http://www.geocities.com/muddin4fun79blazer>www.geocities.com/muddin4fun79blazer</a>

Joined:
Nov 28, 2000
Posts:
3,112
1
Location:
Western Massachusetts
Or when you come around a blind corner and there's Lara toasting the tires off the rims and you swerve to avoid her!
J/K sweet power-braking job! That 383 sures sounds healthy.

8. Grim-Reaper3/4 ton statusAuthor

Joined:
Feb 17, 2000
Posts:
7,385
0
Location:
Atlanta
Static Stability Factor and NHTSA is a bit off base and doesn't include a big variable....DRIVER. Do you know one of the vehicles with the worst roll over percentage with the static test is Mini Vans. One of the best is the Vett. Guess what one ends up on it's lid more.
The current test they are using it a tilt table. they basicly tilt the vehicle till it rolls. That's all fine an dandy but their are so many other variable it doesn't include. Including Driver type, Tire hight, size, rubber compound, road surface, speed, braking, road angle, weather conditions including temp, percipitation, time from beginning of percipitation. I could go on. NHTSA is like consumer reports, their tests often do not reflect reality. Unfortunatly Insurance companies use this data to an advantage. When a Vehicle has a High CG they will raise the rates even if the actual data shows that because of the drivers these have a low insidence of of actual rolls. Then they will change the rules and even though the Vett has a real low CG they will use the actual crash data and raise the rates. It's all BS.
What I think would be impressive is to see if my opinions hold up. Take a class of vehicles such as the SUV' Weed out their roll overs in the ACTUAL data. Find the percentage that roll. Then take a class of vehicls like Sports cars with low CG and get the percentage. THis would show the driver influence if I'm correct. I think that you may find if you twist the stats that way that you will show the vehicle with the High CG will have about the same roll over chance as the low CG vehicle or even less because your pulling driver type information. Now I doubt the NHTSA actuals will include information such as information about vehicle modifications such as lifts. It will probably just lump tham in with SUV. This will drive the statistic higher. Another thing that will drive it higher is the fact that many younger people are more likly to modify a vehicle and you get into some driver statistical stuff that includes the driver being young (inexperiance and prone to being more agressive on the road and the factors to include that they have altered the driving caracteristics you get a double wammy). This will partially offset by the middle age drivers who tend to be very cautious drivers with well maintaind and un altered vehicles.
Then sports car class is again going to be more agressive drivers and again going to have young drivers. You should see cars like Camaro, Firebird, Mustangs etc in that class.
Now you have a compairson of HIGH CG vehicles with moderate drivers against a low CG vehicle with agressive drivers. This will show that the way NHTSA figures are shown are misleading and should include driver types to get a more factual REAL world percentage.
Those percentages NHTSA shows do they include the type of accident that the vehicles were involved in such as Leaving road, speed related, Driver age, Vehicle modified, weather conditions etc?
Reason I ask is it use to be that this informations was collect from accident reports made by the police. Some stuff that goes on accident reports is misleading. Example is there is a box on most accident forms that says "Excessive speed". What is mis leading is if you go through a a intersection and you have a green light and your traveling 5 mph over the speed limit. No big deal right. Well some jack off yapping on a cell phone blows the red light and you T bone them and kill them. They will collect skid mark mesurments and they find your going 5mph over the limit. You don't get a ticket because the Jack off you killed blew the light and this accident was 100% his error. However they did find that you were over the posted so that box gets checked. So now the accident report when shaken down to it's bare statistics show a speed related accident. See how this data gets twisted? See how you T boning a guy that goes through a stop sign on a side street can change the speed limit on a street even though it was not the cause off the accident.
Stats can be twisted to reflect untruths when the Data collected is incomplete or the collection method is flawed.

Women dig dents and flat paint!
75 Jimmy, Dollar
Grim-Reaper

9. muddin4fun3/4 ton status

Joined:
Feb 19, 2001
Posts:
5,644
0
Location:
N Texas
Maybe I should be called "Leadfoot"? LOL!

Thanks on the complament. That motor will 'git it' . I can't wait for the 14 bolt and the 36's and 'git it awn'

Don't hit me, Mr. Moderator... I'll go back on topic... I swear!

<a target="_blank" href=http://www.geocities.com/muddin4fun79blazer>www.geocities.com/muddin4fun79blazer</a>

10. shaggyk51/2 ton status

Joined:
Feb 17, 2000
Posts:
1,610
0
Location:
SE pennsylvania
Ouch.

-matt
<font color=blue>86, 350, 35"TSL's</font color=blue><font color=red>Lop Sop Doi Off-Road</font color=red>
www.chevyhedk5.tripod.com

11. loudnowlouder1/2 ton status

Joined:
Jan 29, 2001
Posts:
539
0
Location:
Ellicott City, MD
i completely agree with you Grim....in fact NHTSA actually begins its discussion of rollovers by saying the largest factor is the driver...they basically say that the worst case scenario is a young male driver driving at night in a suburban area on the weekend after a few drinks in weather conditions less than perfect.

one interesting thing i found was that almost half of all roll overs are in cars, which are supposed to be much less likely to roll, and the rest was split pretty equally between suvs and trucks.

the reason why suv's are considered much more likely to roll is because over 1/3 of all fatal accidents in suv's involve roll overs, whereas only 2% of fatal car accidents are roll overs...

the data is not always easy to interpret, and the only real conclusions that you can draw are simply common sense, if you swerve to miss something in a lifted truck you're more likely to roll than if you do that in a corvette...

with my research i only wanted to show how much more likely i'd be to roll my vehicle in certain situations....if i were in a stock blazer i'd be 30% less likely to roll than in my lifted blazer in the exact same situation.

the variable are endless, and can be studied after the fact, but theres no way to deal with all of them while driving...although i may have a 62% chance that i will roll over, statistics can be misleading...even if theres a 100% chance that something will happen, it doesnt mean that it Will happen.

but i do have a good idea now of how the dynamics of my truck have changed with the lift and tires, i mean i feel the difference everyday when i drive it, but i have a reasonable number now to keep in the back of my head while i'm rushing to get somewhere to keep me from rushing...

12. Zepplin1/2 ton status

Joined:
Aug 29, 2000
Posts:
920
0
Location:
Bay City, MI 48706
I actually just hit a deer on the highway going about 70mph in my 2001 2wd S-10. I barely had a chance to slam on the brakes and if I did swerve(sp) I would probably have rolled it; going that speed. I did about \$4,000 damage and I only had 6,000 miles on the ticker!

74 Blazer
Zepplin
Check out my Blazer
<a target="_blank" href=http://community.webshots.com/user/zepplin1976>http://community.webshots.com/user/zepplin1976</a>

13. prjt_blzr1/2 ton status

Joined:
Mar 4, 2001
Posts:
352
0
Location:
COS, CO
You really need to be careful with how you present data. How much lift is required to raise the CG 4"?? What spring rates are used to calculate body roll and how stiff are the shocks to counter the body roll?? Did the wider tires add to the track width of the vehicle?? How about the 1 ton axles, what did they do to the CG?? There are too many variables that the NHTSA did not take into account on their one size fits all approach. These guys are no better than consumer reports who believe that we should all be driving camrys regardless of vehicle use.

It's good to see some math done on this subject but like all things in the real world ( I design electronics for a living) things don't always behave according to theory or the model does not take enough factors into account. I ran a blazer with 6" of lift for 12 years and 100,000 miles and it never came close to rolling on road at any speed. I've had to dodge more than a few cell phone addicts and was even broadsided by an 8 ton truck once. Citing roll over stats of 90% is a bit careless. It is like saying that 98% of criminals drank milk as a child. It misses too many other things that have direct influence on the topic.

14. Goose1/2 ton status

Joined:
Feb 17, 2000
Posts:
1,127
1
Location:
South Central Kansas
There was an accident the other day around here involving a deer. The guy tried to swerve, lost control, got ejected, and the car landed on him! Luckily(relatively) for him, he landed in the deepest part of the ditch, so the car didn't completely crush him. He is in bad shape. You need to make up your mind, is it going to be you or bambi that's going to get the worst end of it?

15. 84silverK5Registered Member

Joined:
Nov 28, 2001
Posts:
65
0
Location:
Hillsboro Oregon
hehe all this talk about hitting deer makes me have to write too, i had my 77 for like 5 months and i was stupid enough to drive home after being Drunk as a skunk, (which i will never do again) i hit a deer both tires ran it over and i think it made me get some major bumpsteer that threw me in the ditch, then i went up the other side of the ditch and next thing i new i was laying on the roof of my truck and everything inside my truck was laying on my chest, no seatbelt or nothing i was one lucky SOB, but when we flipped it back over i was still able to drive it home, with everyone on the road honking at
me, cuz of my drivers side rear bent Rim, the truck had 38"s and 8inch suspension, if you drive drunk with a lifted blazer your percentages increases to 99 i think

16. DuneRunner1/2 ton status

Joined:
Aug 1, 2001
Posts:
1,252
0
Location:
Fremont CA
Thats Right. Hit bambi (sp) and live, to hose off the grill and undercarage.

Later KEN

DANGIT it's not a bronco!
<a target="_blank" href=http://community.webshots.com/user/kensk5>My Picts</a>

17. txbartman1/2 ton status

Joined:
Jun 1, 2001
Posts:
1,975
0
Location:
Plano, TX
I think that the "statistics" don't tell the real story. What they do tell is that a lifted truck is more unstable than a stock vehicle in most circumstances. And, the more it is lifted, the more unstable in can become. I have a Firebird that I drive like a nut sometimes. I can do hairpin corners at 40 MPH. But, in my rig, you will e hard pressed to find me doing the speed limit.

The problem I find with a lot of SUV drivers is that they think they are in a "big truck" so they can do almost anything. Next time you get rain or ice or snow, watch most people in 4WD SUVs. They will be the fastest on the road. Sure, they have 4WD. That gives them better traction for acceleration than a 2WD. But, know what? All vehicles have 4 wheel braking. And most all have only 2 wheel steering. More accidents occur in bad weather due to breaking or cornering than accelerating! When we get ice down here, I see more bozos in the ditch upside down in the 4x4 Tahoes and Expeditions than I care to say.

I believe that statistically, you would probably find more rollovers in sports cars on the road. And more in stock SUVs. But, I would care to bet that there are actually fewer rollovers on the road as a percentage involving lifted trucks. I know I changed my driving habits when I lifted my truck. I am betting most of you did, too. Does that mean my probability of rolling is less than if I were still stock? Not statistically, but it sure does in reality.

Brian
Check out <a target="_blank" href=http://tx85gmcguy.alloffroad.com>My Jimmy</a> with all her projects!

18. arq1/2 ton status

Joined:
Jan 17, 2001
Posts:
2,017
0
Location:
Imperial Valley/Maricopa
don't forget to load it up and have it for dinner.

ARQ.

72 4x4 CST Blazer
71 4x4 CST Blazer

19. DuneRunner1/2 ton status

Joined:
Aug 1, 2001
Posts:
1,252
0
Location:
Fremont CA
FUR Shure! HHHUU HHUU Get it "FUR"

Ok bad j/k. I got a dry sence of humor...

Later KEN

DANGIT it's not a bronco!
<a target="_blank" href=http://community.webshots.com/user/kensk5>My Picts</a>

20. jcg1/2 ton status

Joined:
Mar 19, 2000
Posts:
660
0
Location:
Rochester, NY
Like everyone has said already, the biggest variable that they leave out is the driver.

Just this past weekend I was in downtown Charleston on my way home from a club and a car blew a stop sign on a side street right in front of me. There was a building there so we didn't see each other till he was just passing the stop sign and he locked up his brakes. I was doing about 35-40 and had to swerve hard in to the oncoming lane to miss him. I cut it hard enough I could feel the rear tires roll under and break loose just before correcting back the otherway. I missed him by about a foot and probably scared him sober as he watched my truck drift past his bumper.

I've driven my truck long enough that actions like that just become instinct... how hard I can get on the brakes, how hard I can swerve, when I should get back on the gas to pull out of it, stuff like that. That would have definitely been a statistic for the roll over files had I not known how my truck would react. With the combination of the 36" TSL's, body lift, and suspension lift, the roof of my truck is 10 inches over stock. According to the statistics I should have rolled for sure. I really wish they would do some real research instead of playing with the numbers like Grim mentioned.

Joe
RIT Mini-Baja www.rit.edu/~bajawww
Team Mudnuts www.mudnuts.org