The Northwestern

[Trackstriper]

...the mass is out near the ends, which is the standard formula for an unstable and difficult to control trailer.

Short of a complete redesign of the entire trailer - what is the solution to this problem? Do the wheels need to be located further back than usual????

Bill, hopefully you won't mind me posing a question regarding this weight distribution as you will apparently have the same issues that I am facing, weight towards the fore and aft ends of the body rather than over the axle. I'd be glad to ask the question as a new subject if you'd prefer not to get sidetracked on this thread. Let me know.

I've heard on this forum that this is an issue for stability at speed. Can someone elaborate on this and is this a problem on a twelve foot trailer or more of a real problem on a thirty foot travel trailer.

Bruce

[wlivesey]

I've been using Andrew's trailer balance estimator to see just how I need to build my frame. What do you think a I should use for the base weight? This is a large trailer - I'm thinking 1500lbs??? Roughly twice that of a typical teardrop.

Thoughts?

[S. Heisley]

Andrew's weight estimate spreadsheet says:

Framing weight, lb per square foot per inch thickness: 3.12

- - - - - - - - - - - - - - - - - - - - -

My 61x98" frame weighs 343 lbs.

Can you make a rough guess from the above?

[wlivesey]

My 61x98" frame weighs 343 lbs.

Thats just for the frame, right? I was considering the entire base weight of the trailer.

Whats the total weight of your trailer?

Thanks,
Bill

[S. Heisley]

wlivesey wrote:

Thats just for the frame, right? I was considering the entire base weight of the trailer.

Whats the total weight of your trailer?

That is the weight for the entire chassis, wheels, axle, frame, lights, all....

Chassis Weight: 343.00 lbs
Roller Jack 17.00
4 Stabilizers (L/W): 16.00
Spare Tire 10.00

I bought my kit from Red Trailers and I think they are quoting the shipping weight, including the box it came in. They give the weights for most of their kits at their website, www.redtrailers.com. Most trailer sites give the weights. For instance, I looked up a light weight 4x8' Harbor Freight trailer a while back and found it was 122 lbs.

It's been a while since worked on my trailer original weights and some things have changed; but, to give you a better idea, below is a portion of my original trailer calculations. Since it's in an Excel spreadsheet, it may loose spacing when I copy it in:

Approx. weight for module listed = 5X8' (Existing=weight found on object)
Existing 61X98" Chassis Weight: 343.00
Existing Roller Jack 17.00
Existing 4 Stabilizers (light load type): 16.00
Existing Spare Tire 10.00
5X8'2" Deck: 1/4"& 3/8" + light frame & foam: 110.64
Two 4X8'2" sides: 1/8" 1/8" + light frame & foam: 90.04
Two 4X5 sides: 1/8" 1/8" + light frame & foam: 55.12
Stationary roof portions, 1/8+1/8" +light frame 25.43
Roof lift hatch 1/8,1/8"+ light frame: 37.07
Existing Roof Vent 3.00
Raised wall weights - estimated 31.33
Existing 16.25x11.5" 2 Brnr SS stove 2.00
actual 6 sm.Lights(bed,kit,doors) 3.00
Existing 13x17" SS sink 3.20
(see left) Built in Beds 51.24
(see data) 12V Battery & box: 53.00
actual Door Handles 3.00
(estimate) Optional Front Curve: 8.27
(estimate) Galley area cabinets 20.67
(estimate) Galley area counters 13.71
Existing 2 sm & 2 lg windows * 19.39
Existing Center board for full bed 6.34
==============================================
SubTotal: 922.45

[angib]

Framing weight, lb per square foot per inch thickness: 3.12

Oooof, Sharon, I don't think that's saying what you think it does.

It's from a page giving weights per square foot of plywood panels (side, roof, etc) and that figure is the weight for framing of panels - for example, the 1x2 timber used to stiffen a plywood sidewall.

Nothing to do with a trailer frame.

Andrew

[brian_bp]

...the mass is out near the ends, which is the standard formula for an unstable and difficult to control trailer.

Short of a complete redesign of the entire trailer - what is the solution to this problem? Do the wheels need to be located further back than usual????

Putting the wheels further back in the same design will lengthen the distance from hitch to axle - that's good for stability. It will also put the centre of the mass further ahead of the axle - this is also good for stability, but limited by the hitch weight capacity of the tow vehicle, so it should not be overdone. (With my trailer and tug, I couldn't shift the axle much at all without causing problems).

Just lengthening the tongue is beneficial - again because it will lengthen the distance from hitch to axle - and will reduce the load on the hitch (likely without doing any harm to stability).

Some combination of the two (longer tongue, slightly shifted axle) could improve stability and control without even changing the hitch load.

This may not be a problem anyway depending on just how the load is distributed within the trailer, so just trying to keep heavy stuff near the middle may be all that is required. I think that it's just something to watch for, rather than a definite problem to be fixed.

[S. Heisley]

Andrew wrote:

S. Heisley wrote:
Framing weight, lb per square foot per inch thickness: 3.12

Oooof, Sharon, I don't think that's saying what you think it does.

It's from a page giving weights per square foot of plywood panels (side, roof, etc) and that figure is the weight for framing of panels - for example, the 1x2 timber used to stiffen a plywood sidewall.

Nothing to do with a trailer frame.

Oh, sorry 'bout that! It's been a while since I visited that weights page and it shows! Thanks for catching that, Andrew! I'm glad you've got my back!

Anyway, the other posting, with my calculation results, should give a general idea.

[TinKicker]

Just something that clicks with me, and probably everybody else in the world can work around, is the fact that I like my trailer tire track width to be the same width as my tow vehicle...or narrower. Why? If I skirt a pothole (or bloated roadkill ) on the outside of my truck tires, I'm pretty certain I'll miss it with my trailer tires too.
With a wider wheel track I'm constantly looking in the side mirror fully expecting the trailer to be two feet off the ground after banging the hole I just barely missed with the truck.
Make sense?
I just received a bare popup frame for the kingly sum of NUTHIN', but I turned around and got rid of it because even though the tires are up underneath, I don't personally like wheelwells in the living area. To each his/her own, but I'll have to sacrifice cabin width for that little caveat. I like to see the wheels.