COG educational thread

GM has PDF same as Ford on the Internet, but I'm not going down that road again!:)

996Pilot wrote:

I can subtract). For my particular truck, the COG of the camper can be placed anywhere from 13.7 inches from the front of the bed to 47.7 inches from the front of the bed. The COG marking on my new Arctic Fox 811 is 43 inches back from the front of the rubber bed bumpers to the COG mark
My RAM 3500 is a short box model and all (newer) RAM short boxes are 6'4" (76 inches) from the front wall to the rear end of the bed. The rear axle center-line is roughly 41 inches from the front of the bed. That puts the manufacturers recommended camper COG anywhere from 27 inches in front of the axle to almost 7 inches behind the rear axle (a total COG envelope of 34 inches front to rear).

Insisting that COG ALWAYS be over or in front of the rear axle is mis-information as manufacturers (and design engineers) likely will tell you it is a function of total weight and balance(COG). They'll also likely tell you that there is an acceptable envelope (like RAM does in published consumer data) at the maximum recommended load. Lighter loads can move further out of the envelope, heavier loads are never recommended (by the manufacturer) but should be closer to the center of the envelope.

You're right on one thing - most people don't understand COG.

So sounds like Dodge engineers know real life better than Ford engineers, or they care more about TC owners?
Kind of suck to know that what you are doing is right and safe, yet you are not within legal specifications.
Any Chevy owner who can tell what is manufacturer recommendation for camper COG ?

Grit dog wrote:

d3500ram wrote:
My COG depends on how much beer I load for a weekend.

Or how much beer I got rid of over the weekend!...

Well, that would really depend on what kind of camper you have and where the black tank is located. If it is a rear bathroom then yes, it might change COG.

Butt, it one has a TC bathroom that is towards the front of the camper's floor and it's associated black tank is forward of the rear axle then it is quite possible that consuming beer and getting rid of it will not change COG no matter how much beer is loaded and consumed.

Butt, all bets are of if one relives the #1 outdoors then yes, consuming beer might change COG.

man there is some serious trolling by a certain poster on this board these days



I'm out

My COG depends on how much beer I load for a weekend.

My truck specified a COG of (A) measurement 39" to (B) measurement 0" as measured from the tailgate. Which means the center of gravity for a TC should be between the tailgate and 39" toward the cab. That puts it at or behind the axle. I know it sounds weird but, that's what was on the tag.

COG is a single point on the camper, that moves. It is static when the camper is stationary, and moves when the camper is in motion. The COG is not at the level vertically of the bed, it has height. With this height it moves under the forces of acceleration, cornering, and deceleration or braking; forward, side-to-side, and to the rear, moving weight from tire to tire. The higher the COG the more weight is transferred.

You get the picture.

Kayteg1 wrote:
The topic about COG got closed for reasons I don't have to understand, but IMHO it shows how little owners understand the technical issues.
So big TC owners are between truck manufacturers who recommend camper COG in front of rear axle and camper manufacturers who build big campers with COG behind rear axle.
I am pretty observant with loading and even with all heavy tools, water and other heavy stuff in truck cabin, having only light cloths in camper rear cabinets, my COG still comes behind rear axle.

COG for the vehicle is NOT a single point. COG is usually expressed as an envelope. COG markings on a camper are placed on one spot (by the manufacturer) based on empty weight, as equipped. We really don't know what the camper COG is with full water and full tanks (black and gray) or worse with partial fresh full gray/black, etc. Then there's really no control where an owner places additional loads, how heavy the loads, etc.

My RAM 3500 has a manufacturers camper COG envelope expressed by measuring from the rear of the truck bed (seems backwards but I can subtract). For my particular truck, the COG of the camper can be placed anywhere from 13.7 inches from the front of the bed to 47.7 inches from the front of the bed. The COG marking on my new Arctic Fox 811 is 43 inches back from the front of the rubber bed bumpers to the COG mark. Based on that, my empty AF811 is within the manufacturers recommended envelope (approximately 4 inches forward of the rear limit of the envelope).

My RAM 3500 is a short box model and all (newer) RAM short boxes are 6'4" (76 inches) from the front wall to the rear end of the bed. The rear axle center-line is roughly 41 inches from the front of the bed. That puts the manufacturers recommended camper COG anywhere from 27 inches in front of the axle to almost 7 inches behind the rear axle (a total COG envelope of 34 inches front to rear).

Insisting that COG ALWAYS be over or in front of the rear axle is mis-information as manufacturers (and design engineers) likely will tell you it is a function of total weight and balance(COG). They'll also likely tell you that there is an acceptable envelope (like RAM does in published consumer data) at the maximum recommended load. Lighter loads can move further out of the envelope, heavier loads are never recommended (by the manufacturer) but should be closer to the center of the envelope.

You're right on one thing - most people don't understand COG.

I have no idea why you would want to send a group email to Ford. The issue you have is not due to a design issue with Ford. The problem is with your camper. My Northstar camper came with COG information and recommendations. The COG is in front of the rear axle. Even so most of the weight is on the rear axle with only a few hundred extra pounds on the front.

My COG was clearly marked when I got the S&S before I repainted it. The COG on RED was 1" in front of center on my rear axle, I think it adds 200lbs to my front axle bringing me to 3,450 on a 4,000lb GAWR and I have over 600lbs left on my rear axle.