Center of gravity calculations

[cowboyconway]

Hey this is great. Thanks for your efforts guys. I was trying to get the center of gravity calculations from two different members simultaneously. One was in Chilliwack and the other in North Van. Neither of them came through before I moved on.

I am wondering if you guys know about this stuff. There were proposed lift height restrictions (that did NOT got through) based upon these center of gravity calculations. Lord know I have plentyof biatching about the height of my truck (44' with 8" suspension and 4" body). All lights and bumpers are legal (bought my own copy of inspection manual at driver's services) but I still get a lot of complaining though most of it turns out good-natured enough. I am just about to put 49's on the truck and it is going to get bigger so I have a good reason to look into this.

Thanks in advance guys!

[skidmark]

Just taking a guess, you can probably take the center of mass height for the vehicle pre-lift and just add the amount of lift to it. Most of the weight is still in the truck itself and not changed much by the tires and wheels.

The steps for calculating the center of mass in my collision investigation text starts on page 109 and ends on page 114.

You may be able to find the center of mass height for your stock vehicle on CATAIR's web site. (http://www.catair.net/asp/carsearch.asp)

[cowboyconway]

that first assumption is way out of wack. The diffs are way heavier, tranny way heavier, tires waay heavier (240 lbs ea without the rims!). That is convenient for the math but has way too many assumptions.


The drive train is decidedly heavier in my truck. That assumption may work for vehicles that are simply lifted but many have had significant changes to the driveline as well which are the lowest portions of the truck. I am willing to bet that my truck though it is lifted has a lower center of mass than it was designed with.

All of the weight that has been added is to the chassis and it is significant.

[cowboyconway]

It's very interesting.

I've cut off a lot of useless body parts, removed a lot of the interior and the third seat, the whole back of the suburban is next but the truck weighs about 1500 lbs more than it did. All of that weight is in the chassis.

Sooo, the body is getting lighter (somewhat) and the chassis is getting heavier (a lot)!

Maybe I should be getting congratulated for making my vehicle safer! I have imporoved the factory braking (4 wheel discs), steering (crossover w/o bump steer and reduced binding), fuel mileage, very likely lower cneter of mass, etc.

Jeez, i'm a pretty likeable guy after all :redneck

[HiThere]

Cowboy, are you going to do some extreme off-roading in your rig? What kind of mileage are you getting now?

[cowboyconway]

I get 15 mpg when very loaded (no propane, on 44's)

I get 18 mpg when unloaded (no propane, on 44's)

The 44's are too small, can take off in third and have high rpms for highway speed. The truck has gobs of power so I will have to get back to you with numbers. the 49's are going to alleviate the consumption quite a bit and metered propane (I have all the parts waiting for the venturi) is going to increase mileage and reduce particulates etc.