How Do You Calculate a Car's Center of Gravity Height?

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Discussion Overview

The discussion revolves around calculating the center of gravity (CG) height of a car, particularly in the context of a drive brake system. Participants explore various methods and considerations for determining CG height, including both theoretical and practical approaches.

Discussion Character

  • Technical explanation
  • Exploratory
  • Homework-related

Main Points Raised

  • One participant expresses uncertainty about how to calculate the CG height and seeks assistance.
  • Another suggests dividing the car into three sections (front, middle, rear) for a simpler calculation if the car's shape is straightforward.
  • A participant refers to an older post related to race car suspension, implying there may be established methods discussed previously.
  • One participant provides detailed dimensions and weights of the car but notes that these figures alone make it impossible to determine the CG height accurately, suggesting it could be between one third and one half of the car's height.
  • Another participant advises gathering all aggregate weights and locating individual CGs to calculate the overall CG position using a formula.
  • A different approach is recommended involving measuring from the pavement to specific points on the car (camshaft and rear axle hub) to approximate the mass centroid.
  • One participant mentions a method involving scales and jacking up the front end of the car, offering to provide a formula if access to scales is available.

Areas of Agreement / Disagreement

Participants do not reach a consensus on a single method for calculating CG height, with multiple competing views and approaches presented throughout the discussion.

Contextual Notes

Participants highlight the need for additional specifications and measurements to accurately determine the CG height, indicating that assumptions about the car's shape and weight distribution may affect the calculations.

Vipcanabis
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Hi, I am calculating about Drive Brake system. Now I am stuck at Hg (I mean car's center gravity of height), I just don't know how to calculate it.
Will anybody help me ? I am really need it
I look forward to your reply
Best Regards,
 
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if the shape of the car is simple like a double box car or box type sedan then simply divide the car in three sections of front , middle and rear, choose an origin. Further it is a basic problem
 
see old post Jul22-09, 11:03 AM

Race car suspension Class
 
Vipcanabis said:
I just don't know how to calculate it.

What don't you know? Measuring the CG height on an actual vehicle or estimating the CG height of your concept car from drawings or maybe even something else.
 
Ok, here I got :
Height x Width x Length = 2740 x 2060 x 7080 (mm) = 107,874 x 81,1 x 278,74 (Inch)
wheelbase = 4085 (mm) = 160,83 (Inch)
Car weight (no load) = 4160 (Kg) = 9152 (lbs)
Front Axle weight = 2130 (Kg) = 4686 (lbs)
Rear Axle weight = 2030 (Kg) = 4466 (lbs)

So, can you help me calculate the Car center of gravity of height (y-axis). I am thanks so much !
Thanks for interesting and helping me
 
Vipcanabis said:
Ok, here I got :
Height x Width x Length = 2740 x 2060 x 7080 (mm) = 107,874 x 81,1 x 278,74 (Inch)
wheelbase = 4085 (mm) = 160,83 (Inch)
Car weight (no load) = 4160 (Kg) = 9152 (lbs)
Front Axle weight = 2130 (Kg) = 4686 (lbs)
Rear Axle weight = 2030 (Kg) = 4466 (lbs)

So, can you help me calculate the Car center of gravity of height (y-axis). I am thanks so much !
Thanks for interesting and helping me

With these numbers, it's impossible to determine exactly. Best guess would be somewhere between one third and one half of the height of your car (which seems really tall!).
 
So, what do I need to determine exactly the CG height ? Please help, just a little more. I got the most specification of the car
 
Get the all aggregate weights.Locate their indiviusal CGs in the car. Then you can easily calulate the CG position by simple CG formula x=(m1x1+m2x2)/(m1+m2) similarly y and z.
Hope it will help you.
 
i recommend the old racers trick of measuring the height from pavement to center of the camshaft and measure height from pavement to center of rear axle hub
draw a line from camshaft center to rear axle center line ( between the two axles) this is good approximation of mass centroid going thru the vehicle ..the other method is to use scales under the rear wheels and jack up the from end at least 30 inches ..this requires scales and if you have access, i can give you formula..i wrote more in other posts. last year
 

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