Superglide vs Sidewinder

BipeFlier wrote: The twisting to which I refer is simple physics.   If you move the load point from, lets say 18 inches in front of the attachment point to the frame to 18 inches at a 90 degree angle that offsets the load to the side.  If the pin weight is 1000 lbs that makes a moment about the point of attachment of 18 X 1000# which equals 18000 inch lbs of torque on the attachment point.   Hold your arm straight out and have the DW push up or down on your hand.  Now bend your elbow 90 degrees and repeat.  Can your shoulder tell the difference?  Same thing on the frame.   Iv'e been wrong before so if you don't agree you are entitled to your opinion and I wll listen to all rebutals.

The attachment point to the frame is 8 bolts between the pin box and the trailer frame mount. All are experiencing sheer stress. When the pin box is in it's normal location the bolts farthest from the king pin experience more sheer stress than the ones closest to the king pin. Rotating the pin box by 90 degrees simply changes which of the 8 bolts have the highest stress and which have the lowest stress. It does not increase the total stress on the 8 bolts. Same thing for the actual welds on the pin box mounting brackets attached to the rest of the trailer frame. The welds furthest from the king pin experience more stress than the others, but total stress is unchanged.   

The arm example is not similiar to a trailer frame. The shoulder is a ball and socket, free to rotate in any direction (to a certain point). It also includes a second pivot point at the elbow. Because of this, when the elbow is bent 90 degrees, the distance from the hand to the shoulder is actually less than when the arm is straight so stress at the shoulder should be less in that case. Anyway, it is not apples to apples. A better example might be holding the arm straight out in front vs. holding the arm straight to the side. But since I know nothing about the strength of the bodies muscles or their attachment points, I don't know which position would 'feel' weaker.

Finally, even IF side stress is somehow greater, the amount of time that the rig is at 90 degrees is such a small percentage of the total towing time. And again IF side stress is greater, it would be happening under low speed conditions as compared to the increased stress on the 8 bolts and frame when towing at say 60 mph and hitting a pot hole, something that is likely to happen much more frequently. Total stress to the 8 bolts and frame is not just the static weight of the king pin, but includes the dynamic weight of bodies in motion.

Guess I am the exception, I have a LWB truck and the Sidewinder.

Dayle1, I'm sorry you feel the need to defend the Sidewinder so vehemently.  I did not say it put MORE stress on the frame, just that it put a twisting stress which is in a different plane than the straight ahead hitch position.

Edited by BipeFlier - 24 Feb 2011 at 8:55pm

I did a lot of research on this subject, and the superglide is the way to go for several reasons.  The piviot point remains over the axle while in travel, so less sway like a TT.

If your hitch is installed correctly, the kingpin is always over the axle. Doesn't make any difference what brand it is.