Level trailer

BenK wrote:
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Last time gmw posted info on his trailers, IIRC, his are more of traditional architecture. Meaning the axle assembly center line is much farther rearward than more modern trailers that,IMHO, have more teeter-tootered weight centered than older, traditional .....snip...

Hi Ben, yes you are correct, my 2012 funfinder does in fact have axles placed rather "farther back, behind the center mass" of the trailer, compared to many of the current gen of trailers.

My two horse Titan horse trailer is also of this rear placed axle design, even more so than the travel trailer (which is typical of horse/stock trailers ).

In my mind and experience, this attribute ( having the axle(s) aft ) does in fact make for a very nice, stable towed trailer.

It was one of the design elements that attracted me to the funfinder. I love towing this thing....tows really well. With the blue ox swaypro WD hitch, both these trailers run down the road very well even on windy days.

Hey folks...gotta keep these things in context...

Im one who says keep the tongue level or pointing slightly down....but know this only new aspect of these new trailer systems. More detail will have eyeballs roll...

Most are out of context...meaning this a SYSTEM comprised of many components...that are ALL interrelated

One example is where the trailer axle symmetrical centerline is in reference to it’s coupler ball center line

Just weighing the tongue in reference to level will have way different values when the axle centerline from trailer to trailer is different

Toss in trailer CG and just this ONE aspect also changes

Last time gmw posted info on his trailers, IIRC, his are more of traditional architecture. Meaning the axle assembly center line is much farther rearward than more modern trailers that,IMHO, have more teeter-tootered weight centered than older, traditional

There is a caster like to these different architecture of where the trailer axle centerline is vs coupler ball centerline

Yet another...there is no one size fits all...but level or pointing slightly down has solved most all trailers I’ve helped solve...hands on and via Internet advice

There is no generic answer for several reasons. The bigger reasons can be length from the jack being weighed to the first axle....and number of axles....and even the length of the equalizer bars (distance between the tires).

Bedlam wrote:
Not the weights I experienced on my single axle flatbed: Based on your measurements, I would expect 4" low at 650 lbs, level at 600 lbs and 4" high at 525 lbs. I don't have a gauge for my dual axle enclosed (used bath scale on my smaller trailer).

I was never very good at science and math class, and I am sure not an engineer, but perhaps the "equalizer" device that sits between the axles of this funfinder trailer has something to do with it ?

Not the weights I experienced on my single axle flatbed: Based on your measurements, I would expect 4" low at 650 lbs, level at 600 lbs and 4" high at 525 lbs. I don't have a gauge for my dual axle enclosed (used bath scale on my smaller trailer).

LOL, you guys are killin' me here....sent me out into the heat !

Tools to gather data: sherline TW gage, level, ruler.

Level, four inches high, and four inches low. And yes, I know, I placed the gauge under the jack which is slightly behind the ball. Get over it.
Tandem axle, leaf sprung, 19' funfinder.

Or we could just hitch up and go camping. Just an idea.

aj, if you don't believe me, go put a scale under the tongue jack on any normal tandem axle trailer. Measure tongue weight nose up and nose down as far as the Jack will go.
Then take the front wheels off and compare tongue weight and then take the rear wheels off (after reinstalling the fronts, to be clear) and check the tongue weight.
Once you verify what I said, come back and dispel your incorrect myth.

I'm not making this stuff up. Go take a Statics course and begin to understand moment arms and X-y-Z components of force and you'll see.

You can even do the same with your single axle example with very light tongue weight, save for the one axle vs the other thing. You'll find the same thing applies.
Thanks for playing.

This is what Ron Gratz (towing guru who used to post often here) posted a few years ago on this interesting thread.:

Yes, trailer nose down will move the CG slightly more forward.
But, the movement is so slight I doubt anyone would be able to detect an influence on towing stability.

Let's assume the distance from ball to axles' midpoint is 200".
Let's also assume the CG is 20" above TT's effective pivot point.
This means a 1" drop in the height of the ball coupler would cause the CG to move forward about 0.1".

With a ball to midpoint distance of 200" and a TW% of 15%, the "level" CG location would be about 30" forward of the axles' midpoint.
If you move the CG from 30" to 30.1" forward of midpoint, you change the TW% from 15% to 15.05%.
I think there would not be a noticeable effect on towing stability.

Personally, I found an improvement by having the nose slightly down compared to level. The most important thing about being slightly nose down has to do with braking. This is from another knowledgeable RV.net poster, also from a few years ago:

During panic braking the nose of the tow vehicle will dive because of weight transfer. When this happens the back of the tow vehicle and front of the trailer will raise up. This is not a good situation because the weight of the trailer will try to lift the back tires of the TV off of the ground. Braking with two tires is not a good thing and you want all tires of the TV braking equally. When the nose of the trailer is down like you have it; it will form a straight line when in panic braking mode; which is a good thing.

Grit dog wrote:

This is almost entirely incorrect, as an extremely nose high trailer compared to and extremely nose low trailer "may" shift a very small amount of the tongue weight fore or aft by virtue of whatever weight is directly above the pivot point (axles) and the change in vertical component of that force (weight) by whatever angle it's at (couple degrees) from plumb or level.

Extreme being a couple/few degrees. Your example is with a single axle trailer that doesnt behave the same as a heavier tandem trailer. Like a tow behind air compressor or small gen set. They don't have a proportionate amount of tongue weight to begin with. They're fairly balanced and actually tow like **** because they dont have enough tongue weight to begin with thats why you can stand them on the back bumper when you pick up the tongue 30-40degrees.

If said tandem axle trailer is a torsion spring trailer, your last statement is incorrect due to the 2 axles not equalizing, in which case nose high and weight on the rear axle would make the front correspondingly heavier, not lighter as the pivot is now further rearward. And with the effective center of axle further rearward, apples to apples the trailer will be more stable and tow better because there's less tail waggin the dog.

This is definitely almost entirely incorrect!