Fun with scales, Tamiya's 5th wheel placement is not bad, but not great.

I got some digital scales to play with and wanted to see if you could change the weight distribution on the Tamiya semis by moving the 5th wheel like you can on the real thing. I learned that you can and that the stock location Tamiya has the 5th wheel manages to take weight off the steer axle. With locked diffs that compounds the poor steering when loaded. As the stock location places the 5th wheel behind the center of the stock suspension. Now the scales I have could only handle 11 pounds, so I would imagine if I had more expensive scales and could put 40lbs on the trailer the weight differences would have been more dramatic than a few ounces.

The first photo is my Grand Hauler with battery, ready to be driven. With 4lbs and 4.1 ounces on the steer axle.
Fun with scales by Gordon Latimer, on Flickr

In this photo I placed a solid aluminum bar with ten pounds of weight, centered between the 5th wheel and the block holding the other end. The truck now has 4lbs and 3.4 ounces on the steer.
Fun with scales by Gordon Latimer, on Flickr

I made a little video talking about changing the 5th wheel placement and managed to get almost a half a pound on the steer axle just by moving where the 5th wheel sits.