"Gary Warner" wrote in message
...

Blocks= 5' Tongue= 4' Weight= 680
Blocks= 6' Tongue= 4' Weight= 600
Blocks= 7' Tongue= 3' Weight= 480

So you can see that the leverage of a longer tongue
gave us almost NO change. But moving out blocks
(axel point) up change things pretty dramatically.


Hey, we had a major discussion (argument) that predicted this outcome a
couple of months ago!

Anyway, my 170 or so lbs didn't change the tongue weight at all.

How far behind the blocks were you sitting?

I am not sure I have the geometry right: Blocks are 7' forward of the very
back. The base frame is 23.5 feet long, so there is 23.5 - 7 = 16.5 feet of
frame ahead of the blocks. The tongue extends 3 feet beyond that, or a
total of 19.5 feet

If you were sitting at the very, very back, then your weight would create a
moment about the blocks of 7' x 170 lbs = 1190 ft-lbs. Due to its
leverage, the tongue will see this as 1190/19.5 = 61 pounds.

I would have expected that you would notice that. If you weren't all the
way to the back, or you did this when the blocks were farther back, then the
difference would be much less.

Another issue you should be aware of is the size of your blocks. If your
block is a 12"x12" you could be introducing a significant error in your
measurements. As the trailer flexes and the scale depresses the trailer
frame will rock forward on the blocks, which can shift the contact point on
the block to the forward edge, effectively moving the pivot point forward up
to 12 inches. This would make a huge difference.

A better way would be to place a piece of pipe between the blocks and
trailer frame so that the contact point is well defined and the block itself
is not creating any moment in the frame. You may want to place a piece of
heavy steel between the pipe and trailer frame so that the pipe doesn't dent
the frame (center the piece of steel so that it is roughly balanced and it
won't effect the measurements).

Rod