Need info on COG for a camper on a trailer.

[Sitting_Bull]

Hey guys, A couple of questions if I may please. I am entertaining the possibility of putting my truck camper on a pull behind car hauler trailer. My intention is to finish it all and enclose it so that it is appealing . My wife loves our camper layout and would not find the same in a TT. Plus we do not want to go into debt for a TT .
1) What are your opinions and experiences with this?
2) What size trailer would you recommend? I have a 10' camper for a long box.
3) My camper indicates where the centre of gravity is and on my truck, and it is slightly ahead of the rear axle. If I put the camper on a tandem axle trailed, where should that COG line be? In front of both axles? In between both axles?
4) Any web sites where I could see what guys have done with their units?
Thanks for your help and feel free to comment on anything.

[Sitting_Bull]

That is the answer I was looking for. Thank you.

wnjj wrote:

Sitting Bull wrote:
.....
I guess I need to understand the proper positioning for the COG over tandem axles as well as proper tongue weight.....

If you mean what the trailer should end up with, you want the COG of your cargo (camper + stuff in the storage areas) to be 10-15% ahead of the centerline between the 2 axles.

In other words, measure from the hitch coupler back to a place directly between the front and rear axles. Then go 10-15% of the way toward the front. That is where your trailer wants its load COG. Putting the camper COG right there will work but if you add cargo under the cabover, you'll want to move the camper back some to compensate.

When I checked my 16' cargo trailer in the past, I believe the deck was such that exactly half way from front to back was between 10-15% of the way forward. So if I load a perfect symmetric load it would end up with ideal tongue weight. This is why there is more deck in front of the axles then behind.

[Sitting_Bull]

deltabravo wrote:
One thing to start look at before you get too committed to doing this is to see if the space between the jacks is wide enough to back a trailer under the camper.

Great point! I will have to wait t'ill the snow is gone out of the storage area.

[deltabravo]

One thing to start look at before you get too committed to doing this is to see if the space between the jacks is wide enough to back a trailer under the camper.

[deltabravo]

PJ Trailers makes some very nice trailers.

That's what I hauled my Jeep on. My first trailer was a 16' 7k. I was loaded near the max weight rating. The trailer possibly had a bent axle or something, because it kept eating tires at one wheel position, even though I only put like 5000 miles on it.

I traded that in on a 10k 18' with beaver tail and rear stabilizer jacks. It was a nice trailer, but I never used it because I gave up Jeeping.

The white trailer above looks like a PJ Trailer.

[deltabravo]

Sitting Bull wrote:
4) Any web sites where I could see what guys have done with their units?
Thanks for your help and feel free to comment on anything.

Pirate 4x4 Forum

[wnjj]

Sitting Bull wrote:
.....
I guess I need to understand the proper positioning for the COG over tandem axles as well as proper tongue weight.....

If you mean what the trailer should end up with, you want the COG of your cargo (camper + stuff in the storage areas) to be 10-15% ahead of the centerline between the 2 axles.

In other words, measure from the hitch coupler back to a place directly between the front and rear axles. Then go 10-15% of the way toward the front. That is where your trailer wants its load COG. Putting the camper COG right there will work but if you add cargo under the cabover, you'll want to move the camper back some to compensate.

When I checked my 16' cargo trailer in the past, I believe the deck was such that exactly half way from front to back was between 10-15% of the way forward. So if I load a perfect symmetric load it would end up with ideal tongue weight. This is why there is more deck in front of the axles then behind.

[bobndot]

see the end of the first post for ideas ........members projects.....scroll to bottom "general unsorted"


http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/21558012/srt/pa/pging/1/page/1

[Reality_Check]

Sitting Bull wrote:
.....
I guess I need to understand the proper positioning for the COG over tandem axles as well as proper tongue weight.....

You're asking for a definitive answer to a vague question. The only thing the 'COG' sticker on the camper refers to is where the mark is when empty as constructed. It's a general guide line.

Put the camper on the trailer and go weight the tongue.. then you'll know. Then add all your crap...then you'll know more. It's trial and error. Not rocket science.

The rigs you see that have been successful are accomplished via good luck or school of hard knocks. End result is the same, success (hopefully) but there is no written rule for this stuff.

Take this answer in stride.. it's a Crown night...4 and counting 🙂

[Sitting_Bull]

Thanks for the replies, My plan would be to build a nice enclosure under the bed to match the camper and use it for either the quad or extra storage. I thought of a goose neck but,I think I would lose some valuable space out of the box of the pick up.
I guess I need to understand the proper positioning for the COG over tandem axles as well as proper tongue weight.
I have to do all this so that it is safe and looks great. Not something that has been slapped together.
Any more advice or comments are welcomed.

[wintersun]

A benefit of putting a camper on a flat bed or trailer is in having the option of enclosing the space below the cab over section. If you do this and put gear in this space then the COG will shift forward considerably.

Safest to have the COG of the camper directly over the rear axle as would be the case in the bed of a pickup truck. Then the added gear will be supported by the front axle and minimize the tongue load at the hitch.

The forward space is a great location for extra water or motor fuel or a generator or a larger battery bank. The heavy duty popup trailers are designed along this approach with a large storage platform at the front of the trailer.

http://www.rmrv.com/RVShowroom/tabid/1630/Type/View/ID/66666/2016-Tent-Trailer-STARCRAFT-COMET-C-12RT.aspx

[Bedlam]

Have you thought about a small goose neck trailer that would turn the cab over of the TC into a "bed over"? This would make a mini fifth wheel that would be very maneuverable.

[RoyB]

I always thought this google images photo was a neat looking arrangement of putting the TC shell on the back of a trailer.

Lots of space to build-in cabinets for more storage space accessible from the outside...


After all said and done I guess maybe a TT with more living space inside would be better to get???

Roy Ken

[JIMNLIN]

1. I've seen some really sweet looking TC's on a trailer rigs that were well thought out and I've seen some that were simply tied down on a trailer with small nylon straps.

2. Car haulers generally come in a 7k GVWR with two 3500 lb axles. The 16' I had weighed 1800 lbs and had around 5200 lb payload.
Or a 10k GVWR trailer with two 5.2k axles. My 18 footer weighs 2520 lbs which leaves around 7400-7500 lbs for its payload.
Or a 14k GVWR with two 7k axles. These trailers can weigh around 3500 -3700 lbs.
Your campers weight plus the other "fixin's" your going to add will determine how much trailer you need.

3. You will need about 10-13 percent of the trailers gross for a hitch weight. You may know where the COG on the TC is but other "fixins" you add will change that. I wouldn't tie the TC down permanently till you get the right hitch weight on the trailer.

4. I would try a google for you tubes and how to do it. Good luck

[mabynack]

I use to make car haulers using discarded house trailer axles. Something like that with a pickup bed on it would be a great match for what you're talking about. The COG should give you a pin weight between 10% and 20% of the total weight on the trailer. I would tend to err on the heavier side because I've seen some serious issues from locating the CG too far aft.