Smitty...few questions re: your G-wagen...
03-14-2006, 10:56 AM
#1
AudiWorld Super User
Thread Starter
Smitty...few questions re: your G-wagen...
1) what size wheels/tires are currently on?
2) what's the modified track width?
3) what year is it?
The data for a stock '04 is:
TIP-OVER STABILITY RATIO = 0.96 - UNSTABLE
NHTSA Star Rating (out of five) *
TRACK WIDTH: 58 inches (front and rear)
Increasing ride height hurts the stability, while increasing the track width helps...so you may have broken even with the new wheels.
Gimme some numbers and I can tell you <i>about</i> how far you can push it before needing to install a kickstand. :P<ul><li><a href="https://forums.audiworld.com/midatlantic/msgs/126245.phtml">Leesburg Mall post</a></li></ul>
2) what's the modified track width?
3) what year is it?
The data for a stock '04 is:
TIP-OVER STABILITY RATIO = 0.96 - UNSTABLE
NHTSA Star Rating (out of five) *
TRACK WIDTH: 58 inches (front and rear)
Increasing ride height hurts the stability, while increasing the track width helps...so you may have broken even with the new wheels.
Gimme some numbers and I can tell you <i>about</i> how far you can push it before needing to install a kickstand. :P<ul><li><a href="https://forums.audiworld.com/midatlantic/msgs/126245.phtml">Leesburg Mall post</a></li></ul>
03-15-2006, 05:17 AM
#5
AudiWorld Super User
Thread Starter
OK, with the new wheels on, you increased your tip-over stability...
<b>Stock:</b>
Track width = 58"
Center of Gravity height = 30.32"
Tip-Over Stability Ratio = 0.956
Tip-Over angle = 43.725°
<b>Wheels:</b>
Track width = 69.66"
Center of Gravity height = 32.62"
Tip-Over Stability Ratio = 1.07
Tip-Over angle = 46.877°
So while your new wheels increase the CG height, they are offset so as to increase the track width by a ratio of about 2.5:1 to the CG increase. Now, I know I don't need a disclaimer here...so I'm not gonna type one. Theres a bunch of room for margin of error, both static (tire flex, locations of occupants & gear, fuel, etc.) and dynamic (tire rebound/bounce, wind, suspension, etc.)...but I hope that gives you an idea of how far you can <i>theoretically</i> push it without outriggers. :P
Track width = 58"
Center of Gravity height = 30.32"
Tip-Over Stability Ratio = 0.956
Tip-Over angle = 43.725°
<b>Wheels:</b>
Track width = 69.66"
Center of Gravity height = 32.62"
Tip-Over Stability Ratio = 1.07
Tip-Over angle = 46.877°
So while your new wheels increase the CG height, they are offset so as to increase the track width by a ratio of about 2.5:1 to the CG increase. Now, I know I don't need a disclaimer here...so I'm not gonna type one. Theres a bunch of room for margin of error, both static (tire flex, locations of occupants & gear, fuel, etc.) and dynamic (tire rebound/bounce, wind, suspension, etc.)...but I hope that gives you an idea of how far you can <i>theoretically</i> push it without outriggers. :P
03-15-2006, 05:22 AM
#6
AudiWorld Super User
Thread Starter
Oh, and here's the data printout for an '02 G-wagen...
2002 MERCEDES BENZ G500 4DR 4X4 UTILITY
CURB WEIGHT: 5423 lbs. 2460 kg.
Curb Weight Distribution - Front: 60 % Rear: 40 %
Gross Vehicle Weight Rating: 6834 lbs. 3100 kg.
Number of Tires on Vehicle: 4
Drive Wheels: All Wheel Drive
HORIZONTAL DIMENSIONS
____Inches___Feet___Meters
Total Length 184 15.33 4.67
Wheelbase: 112 9.33 2.84
Front Bumper to Front Axle 30 2.50 0.76
Front Bumper to Front of Front Well 10 0.83 0.25
Front Bumper to Front of Hood 3 0.25 0.08
Front Bumper to Base of Windshield 58 4.83 1.47
Front Bumper to Top of Windshield 66 5.50 1.68
Rear Bumper to Rear Axle 42 3.50 1.07
Rear Bumper to Rear of Rear Well 11 0.92 0.28
Rear Bumper to Rear of Trunk 4 0.33 0.10
Rear Bumper to Base of Rear Window 6 0.50 0.15
WIDTH DIMENSIONS
Maximum Width 69 5.75 1.75
Front Track 58 4.83 1.47
Rear Track 58 4.83 1.47
VERTICAL DIMENSIONS
Inches Feet Meters
Height 76 6.33 1.93
Ground to:
Front Bumper (Top) 24 2.00 0.61
Headlight - center 35 2.92 0.89
Hood - top front 40 3.33 1.02
Base of windshield 52 4.33 1.32
Rear Bumper - top 25 2.08 0.63
Trunk - top rear 41 3.42 1.04
Base of rear window 51 4.25 1.30
INTERIOR DIMENSIONS
Inches Feet Meters
Front Seat Shoulder Width 54 4.50 1.37
Front Seat to Headliner 42 3.50 1.07
Front Leg - seatback to floor (max) 53 4.42 1.35
Rear Seat Shoulder Width 54 4.50 1.37
Rear Seat to Headliner 40 3.33 1.02
Rear Leg - seatback to floor (min) 42 3.50 1.07
Seatbelts: 3pt - front and rear
Airbags: FRONT SEAT AIRBAGS
STEERING DATA
Turning Circle (Diameter) 516 43.00 13.11
Steering Ratio: __.__:1
Wheel Radius: 14 1.17 0.36
Tire Size (OEM): P265/60R18
ACCELERATION & BRAKING INFORMATION
Brake Type: ALL DISC
ABS System: ALL WHEEL ABS
Braking, 60 mph -> 0 (Hard pedal, no skid, dry pavement):
d = 129 ft t = 2.9 sec. a =-30.0 ft/sec/sec G-force = -0.93
ACCELERATION:
0->30 mph t = 2.9 sec. a = 15.2 ft/sec/sec G-force = 0.47
0->60 mph t = 7.5 sec. a = 11.7 ft/sec/sec G-force = 0.36
45->65 mph t = 4.1 sec. a = 7.2 ft/sec/sec G-force = 0.22
Transmission Type: 5spd AUTOMATIC
NOTES:
Federal Bumper Standard Requirements = NO REQUIREMENT
N.S.D.C. = 2002 - 2005
OTHER INFORMATION
TIP-OVER STABILITY RATIO = 0.96 UNSTABLE
NHTSA Star Rating (calculated) *
CENTER OF GRAVITY (No Load):
Inches behind front axle = 44.80
Inches in front of rear axle = 67.20
Inches from side of vehicle = 34.50
Inches from ground = 30.32
Inches from front corner = 82.37
Inches from rear corner = 114.52
Inches from front bumper = 74.80
Inches from rear bumper = 109.20
MOMENTS OF INERTIA APPROXIMATIONS (No Load):
YAW MOMENT OF INERTIA = 4242.69 lb-ft-sec^2
PITCH MOMENT OF INERTIA = 4416.76 lb-ft-sec^2
ROLL MOMENT OF INERTIA = 958.06 lb-ft-sec^2
FRONT PROFILE INFORMATION
ANGLE FRONT BUMPER TO HOOD FRONT = 79.4 deg
ANGLE FRONT OF HOOD TO WINDSHIELD BASE = 12.3 deg
ANGLE FRONT OF HOOD TO WINDSHIELD TOP = 28.4 deg
ANGLE OF WINDSHIELD = 70.0 deg
ANGLE OF STEERING TIRES AT MAX TURN = 24.9 deg
FIRST APPROXIMATION CRUSH FACTORS:
Speed Equivalent (mph) of Kinetic Energy (KE) used in
causing crush or indentation may be evaluated using the
following formula, the appropriate Crush Factor (CF), and
Maximum Indentation Depth (MID), in feet:
V(mph) = Sqr root of (30 * CF * MID)
KE Equivalent Speed (Front/Rear/Side) = 21 CF
Bullet vehicle IMPACT SPEED estimation
based on TARGET VEHICLE damage ONLY = 27 CF
(Tested for Rear/Side Impact only)
These CF values are based upon analysis of NHTSA Barrier Crash
data, and from over 1000 vehicle accidents where independant
evaluation of speed was possible. (These are NOT 'A', 'B', 'C',
or 'G' values)
The Rear Impact data with more than 2-3 inches of crush damage
should be looked at carefully, since some vehicles have very weak
trunk & fender strength. Therefore, on some cars, esp. GM, your
estimate from the rear crush data may be high by as much as 4-5
mph (on a crush of 18 inches).
CURB WEIGHT: 5423 lbs. 2460 kg.
Curb Weight Distribution - Front: 60 % Rear: 40 %
Gross Vehicle Weight Rating: 6834 lbs. 3100 kg.
Number of Tires on Vehicle: 4
Drive Wheels: All Wheel Drive
HORIZONTAL DIMENSIONS
____Inches___Feet___Meters
Total Length 184 15.33 4.67
Wheelbase: 112 9.33 2.84
Front Bumper to Front Axle 30 2.50 0.76
Front Bumper to Front of Front Well 10 0.83 0.25
Front Bumper to Front of Hood 3 0.25 0.08
Front Bumper to Base of Windshield 58 4.83 1.47
Front Bumper to Top of Windshield 66 5.50 1.68
Rear Bumper to Rear Axle 42 3.50 1.07
Rear Bumper to Rear of Rear Well 11 0.92 0.28
Rear Bumper to Rear of Trunk 4 0.33 0.10
Rear Bumper to Base of Rear Window 6 0.50 0.15
WIDTH DIMENSIONS
Maximum Width 69 5.75 1.75
Front Track 58 4.83 1.47
Rear Track 58 4.83 1.47
VERTICAL DIMENSIONS
Inches Feet Meters
Height 76 6.33 1.93
Ground to:
Front Bumper (Top) 24 2.00 0.61
Headlight - center 35 2.92 0.89
Hood - top front 40 3.33 1.02
Base of windshield 52 4.33 1.32
Rear Bumper - top 25 2.08 0.63
Trunk - top rear 41 3.42 1.04
Base of rear window 51 4.25 1.30
INTERIOR DIMENSIONS
Inches Feet Meters
Front Seat Shoulder Width 54 4.50 1.37
Front Seat to Headliner 42 3.50 1.07
Front Leg - seatback to floor (max) 53 4.42 1.35
Rear Seat Shoulder Width 54 4.50 1.37
Rear Seat to Headliner 40 3.33 1.02
Rear Leg - seatback to floor (min) 42 3.50 1.07
Seatbelts: 3pt - front and rear
Airbags: FRONT SEAT AIRBAGS
STEERING DATA
Turning Circle (Diameter) 516 43.00 13.11
Steering Ratio: __.__:1
Wheel Radius: 14 1.17 0.36
Tire Size (OEM): P265/60R18
ACCELERATION & BRAKING INFORMATION
Brake Type: ALL DISC
ABS System: ALL WHEEL ABS
Braking, 60 mph -> 0 (Hard pedal, no skid, dry pavement):
d = 129 ft t = 2.9 sec. a =-30.0 ft/sec/sec G-force = -0.93
ACCELERATION:
0->30 mph t = 2.9 sec. a = 15.2 ft/sec/sec G-force = 0.47
0->60 mph t = 7.5 sec. a = 11.7 ft/sec/sec G-force = 0.36
45->65 mph t = 4.1 sec. a = 7.2 ft/sec/sec G-force = 0.22
Transmission Type: 5spd AUTOMATIC
NOTES:
Federal Bumper Standard Requirements = NO REQUIREMENT
N.S.D.C. = 2002 - 2005
OTHER INFORMATION
TIP-OVER STABILITY RATIO = 0.96 UNSTABLE
NHTSA Star Rating (calculated) *
CENTER OF GRAVITY (No Load):
Inches behind front axle = 44.80
Inches in front of rear axle = 67.20
Inches from side of vehicle = 34.50
Inches from ground = 30.32
Inches from front corner = 82.37
Inches from rear corner = 114.52
Inches from front bumper = 74.80
Inches from rear bumper = 109.20
MOMENTS OF INERTIA APPROXIMATIONS (No Load):
YAW MOMENT OF INERTIA = 4242.69 lb-ft-sec^2
PITCH MOMENT OF INERTIA = 4416.76 lb-ft-sec^2
ROLL MOMENT OF INERTIA = 958.06 lb-ft-sec^2
FRONT PROFILE INFORMATION
ANGLE FRONT BUMPER TO HOOD FRONT = 79.4 deg
ANGLE FRONT OF HOOD TO WINDSHIELD BASE = 12.3 deg
ANGLE FRONT OF HOOD TO WINDSHIELD TOP = 28.4 deg
ANGLE OF WINDSHIELD = 70.0 deg
ANGLE OF STEERING TIRES AT MAX TURN = 24.9 deg
FIRST APPROXIMATION CRUSH FACTORS:
Speed Equivalent (mph) of Kinetic Energy (KE) used in
causing crush or indentation may be evaluated using the
following formula, the appropriate Crush Factor (CF), and
Maximum Indentation Depth (MID), in feet:
V(mph) = Sqr root of (30 * CF * MID)
KE Equivalent Speed (Front/Rear/Side) = 21 CF
Bullet vehicle IMPACT SPEED estimation
based on TARGET VEHICLE damage ONLY = 27 CF
(Tested for Rear/Side Impact only)
These CF values are based upon analysis of NHTSA Barrier Crash
data, and from over 1000 vehicle accidents where independant
evaluation of speed was possible. (These are NOT 'A', 'B', 'C',
or 'G' values)
The Rear Impact data with more than 2-3 inches of crush damage
should be looked at carefully, since some vehicles have very weak
trunk & fender strength. Therefore, on some cars, esp. GM, your
estimate from the rear crush data may be high by as much as 4-5
mph (on a crush of 18 inches).
03-15-2006, 07:19 AM
#7
AudiWorld Super User
Thread Starter
Crush Factors...basically how soft or rigid the car is. :P
There is a scientific method of estimating the approximate velocity necessary to result in a measured amount of crush to the profile of a vehicle.
Basically, take a vehicle that has been in an accident; a G-wagen that hits a pole, for instance. The front of the vehicle, from a birds-eye view, that used to look like this:
|____________________|
...now looks like this:
|____--***-__________|
...we can take incremental (every 6" or so) measurements of the inward crush (to find the 'area under the curve', from algebra/calculus) relative to the original profile and formulate values for energy required and, after comparing it to the crash test data, come up with a pretty close estimate for velocity at the time of impact. Pretty cool, huh?
Almost every car is different; a '64 Impala will show a lot less crush than a '06 Impala for the same speed at impact. Crush is good in terms of protecting the occupants; the more energy used to crush the vehicle, the less forces are applied to the occupants...they slow down more gradually (lower g-forces) opposed to jarring to a stop. Unfortunately, low-speed collisions tend to total newer cars for the sake of the occupants. C'est la vie. :P
Basically, take a vehicle that has been in an accident; a G-wagen that hits a pole, for instance. The front of the vehicle, from a birds-eye view, that used to look like this:
|____________________|
...now looks like this:
|____--***-__________|
...we can take incremental (every 6" or so) measurements of the inward crush (to find the 'area under the curve', from algebra/calculus) relative to the original profile and formulate values for energy required and, after comparing it to the crash test data, come up with a pretty close estimate for velocity at the time of impact. Pretty cool, huh?
Almost every car is different; a '64 Impala will show a lot less crush than a '06 Impala for the same speed at impact. Crush is good in terms of protecting the occupants; the more energy used to crush the vehicle, the less forces are applied to the occupants...they slow down more gradually (lower g-forces) opposed to jarring to a stop. Unfortunately, low-speed collisions tend to total newer cars for the sake of the occupants. C'est la vie. :P
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03-15-2006, 10:44 AM
#8
AudiWorld Super User
Thread Starter
Welp, I worked with what I had...it may not be deadnuts.
That number is based on the tire widths...a more accurate way may be to base it on the wheels.
You said the new wheels were 8" wide w/ 5.25" bckspacing. I'm assuming that means the inside of the rim to the hub face is 5.25"?...or vice versa? If it is VV, then the track is more like 8.66; again, based on the tire widths.
Reading depositions has made my head hurt, I'll check the numbers later. :P
You said the new wheels were 8" wide w/ 5.25" bckspacing. I'm assuming that means the inside of the rim to the hub face is 5.25"?...or vice versa? If it is VV, then the track is more like 8.66; again, based on the tire widths.
Reading depositions has made my head hurt, I'll check the numbers later. :P
03-16-2006, 04:25 AM
#9
AudiWorld Super User
Thread Starter
Naw, accident reconstruction...
...my company (me) is hired as engineering consultants and, if needed, as experts in court. Part of our investigations always includes reading depos of those involved...makes my head hurt sometimes. :P
Each of us engineers has different specialties...I'm developing a niche in everything auto (accidents, fires, thefts, etc.). I have to go to Waldorf today to look at a recovered vehicle for an insurance company; they want to know if/how it was stolen (forced entry, defeated ignition, etc.)...fun stuff!
Each of us engineers has different specialties...I'm developing a niche in everything auto (accidents, fires, thefts, etc.). I have to go to Waldorf today to look at a recovered vehicle for an insurance company; they want to know if/how it was stolen (forced entry, defeated ignition, etc.)...fun stuff!