Trailer Axel / Physics Puzzler
 

"Gary Warner" wrote in message
...


PUZZLER: Does the axel "balance" the weight over the
axel or over the wheels? .


Over the wheels.

To be precise, over the point at which the wheel contacts the ground, which
had better be directly under the axel.


A thought just crossed my mind: You should also check the tongue weight
when the trailer is empty. From your description it sounds like you won't
have a problem, but I have seen trailers built for a center engine boat that
had negative tongue weight when the boat was NOT on the trailer.

Rod

Trailer Axel / Physics Puzzler
 

A clarification on my previous answer:


"Gary Warner" wrote in message
...


The thing is, it's not just a straight
across axel. Well, the axel goes straight across, but coming from the
center of the axel is a 6" arm that goes back to the spindle. In other
words,
the tires are off-set 6" behind where the axel is.

By definition, an axle (vs axel, which is a figure skating jump) is the
shaft on which the wheels rotate about. In other words, axle = spindle.
The tube that goes across the trailer that contains the torsion bar would be
called something else.

So, the pivot point is at the wheel, where the spindle/axle is.

Sorry for the confusion.

Rod

Trailer Axel / Physics Puzzler
 

"Gary Warner" wrote in message
...

Thanks all for the replys.

I will call the company and ask them too, but I always like
the comments and thought processes I get here.



Since the axle is fixed to the frame, it is part of the frame. The spindles
go where the axle would go if it were straight across. Consider the vector
through the center of mass of the boat and trailer. It should be just
forward of the center of the spindles which is where the upward vector from
the ground passes up. The remainder of the torque is supplied by the force
upwards on the tongue. Just remember that the sum of the torques about any
point must be zero. So pick a convenient point and draw the force vectors.

del cecchi

Trailer Axel / Physics Puzzler
 

"basskisser" wrote in message
om...

Your current thinking is correct, if all things equal, AND if you
didn't consider the torsion of the spring.

What?????

The torsional forces can not have any effect on the trailer balace as long
as the wheels are round or allowed to rotate.

Again, if you put the wheel
at the center of gravity of the boat, it will be balanced.

No, it would need to be at the center of gravity of the boat + trailer.

Trouble is,
when this is done, will the boat's C.G. be at the C.G. of the trailer?

Probably not. Which is why you would want to use the C.G. of boat + trailer
for any calculations.


See, you could load the boat on the trailer, and the CG of the boat
could be far enough behind that the tongue has a negative load.

A universally true statement. Take any boat and trailer, load the boat far
enough back and the tongue weight will go negative.

What's your point?

Rod

Trailer Axel / Physics Puzzler
 

Gary,
When using tandem axles some method of equalizing the weight must be used to
keep one set of axles from being over loaded. The trailer will rarely be
setting perfectly level and without an equalizer the tires will be unequally
loaded as well. In the case of leaf springs, it's done using a common,
rotating equalizer. In your case, I'm not sure. I'd ask the manufacturer
of the axles. This catalog shows the normal axle setup and may show your's
as well.
http://www.championtrailers.com/catalog_pdf.htm


"Gary Warner" wrote in message
...

"Harry Krause" wrote:

Out of curiosity, how does one place the axle? Is it at the centerpoint?
I think you'd want it a bit forward of the centerline. I built a box
trailer some years ago, and was advised to have the axle forward of
center under the box. I knew why at the time, but I've since forgotten.


I'm not an expert (obviously) but our thinking is: We experimented
with the trailer WITH the boat on it to find a point that is just BACK
of the true center of gravity. A single axel placed right AT the center
of gravity would give essentiall no tongue weight. Moving the single
axel back just a little gives some tongue weight.

In our case we are putting tandem axels. So one axel will go forward
of the point we found and the other back of that point by the same
distance.

Trailer Axel / Physics Puzzler
 

"Rod McInnis" wrote in message
...

A thought just crossed my mind: You should also check the tongue weight
when the trailer is empty. From your description it sounds like you won't
have a problem, but I have seen trailers built for a center engine boat
that
had negative tongue weight when the boat was NOT on the trailer.


That's a great point and one I hadn't thought of. Will do it.


Rod

Trailer Axel / Physics Puzzler
 

"Rod McInnis" wrote in message
...
A clarification on my previous answer:


By definition, an axle (vs axel, which is a figure skating jump) is the
shaft on which the wheels rotate about. In other words, axle = spindle.
The tube that goes across the trailer that contains the torsion bar would
be
called something else.


Makes sense and well said. Thanks.

Trailer Axel / Physics Puzzler
 

"QLW" wrote:


Gary,
When using tandem axles some method of equalizing the weight must be used
to
keep one set of axles from being over loaded. The trailer will rarely be
setting perfectly level and without an equalizer the tires will be
unequally
loaded as well. In the case of leaf springs, it's done using a common,
rotating equalizer. In your case, I'm not sure. I'd ask the
manufacturer
of the axles. This catalog shows the normal axle setup and may show
your's
as well.
http://www.championtrailers.com/catalog_pdf.htm


Question: On this axle each wheel has independent suspension. Would this
take care of the situation you mentioned?

Seems to me it might. For example, say the trailer was on totall level
gound
except for one wheel which was on a rock sticking up 3" above level.

Hmmm, maybe not. I just don't know.

Trailer Axel / Physics Puzzler
 

On Mon, 26 Jan 2004 13:33:17 +0000, Gary Warner wrote:


Thanks all for the replys.

I will call the company and ask them too, but I always like the comments and
thought processes I get here.

...then you are one sick and twisted individual! :)

Lloyd

Trailer Axel / Physics Puzzler
 

Lloyd Sumpter wrote:

On Mon, 26 Jan 2004 13:33:17 +0000, Gary Warner wrote:


Thanks all for the replys.

I will call the company and ask them too, but I always like the comments and
thought processes I get here.

...then you are one sick and twisted individual! :)

Lloyd


This from a man who used to have a relationship with a woman known as
Vinyl Valerie.

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