Center of Gravity Truck Camper

[egarant]

I’m considering an Arctic Fox 1140 which has a COG marked as 55.25” from the front wall of the camper.  That puts the COG about 2” behind my rear axle.  I am seeing Lance’s and Host’s that have COG’s of 60+”s!  How are those side entry truck campers being safely loaded on ANY truck that is not a chassis cab?

[jimh406]

I seem to remember that the measurement method is different among a few companies.  However, COG isn't static.  It will move based on where you put your supplies/water/gear, etc.  Also, the affect on your handling will vary depending on how many people are in the vehicle and/or what supplies you carry.

Practically speaking, larger campers are built for DRWs. If you have one that is in good working order, you are probably good to go. Sure, your truck may be worse than someone else's or a little better.

However, if you want a more capable truck, there's not a lot wrong with overkill.

[AF1]

Trust that COG is COG, the same issue applies to a chassis cab flat bed, even when ‘well under’ it’s 19,500# GVWR. Even though cab to axle distance (i.e. a 60” CA) is about 4” longer with a class 4 or 5 CC, this light FA effect is exacerbated by a flat bed’s longer (say 9’-4” vs 8’) than the standard pick-up’s 8’ bed…In either case, adding a leaf (other than to address cargo weight or sag) can help..

[4x4ord]

I don’t know weights or dimensions of the campers or your truck but just taking a WAG say a camper has a weight of 4500 lbs and places its COG 8” behind the rear axle. The said camper will cause a moment of force of 4500 x 8 inch lbs in a clockwise direction about your rear axle. If your truck has a wheel base of 176” the weight being lifted off your trucks front axle would be 4500 x 8/176 or 205 lbs. That would be approximately equivalent to the weight taken off your front axle when a trailer with a tongue weight of 750 lbs is placed on a ball hitch located 48” behind your rear axle.

[Grit_dog]

Thanks for that. Good explanation of how little weight is actually removed from the FA. 

[Grit_dog]

Because it’s just fine. 
Think about it. Do a moment diagram or think of a teeter totter. 
You put a fat dude on one end at the very end and you put a 5 year old opposite side, 1’ back from the pivot point, even though that little kid is doing all he can, he ain’t gonna move the fat guy. Not even close
in this case, the teeter totter is your truck and the rear axle is the pivot. 
the fat guy is your 1000lb diesel and cab and passengers and heavy front axle. And the 5 year old is the leeetle bit of weight that is on the other side of the pivot when the cog is behind the axle. 
it ain’t gonna move the fat guy. 
now if the fat guy was a skinny dude (half ton with a half aluminum engine) and the 5 year old was really a teenager, that teenage would come a lot closer to moving the skinny guy. 
as long as you have a fat dude and a 5 year old, you’re good. 

[mkirsch]

Makes it hard to visualize when the "fat guy" weighs 1000lbs, and the "skinny kid" weighs 6000lbs.

The way I'd explain it is more akin to the classic teeter totter example: You've got the "fat guy" sitting close to the fulcrum, with the "skinny kid" sitting way out on the end, and they balance.