Quote:
Originally Posted by mjlaupp
Please use the correct terms in the correct context as defined by the SME - Society of Mechanical Engineers. The following is from the ToolingU, Mechanical Systems Training web page: http://www.toolingu.com/definition-5...hock-load.html
Static Load - "A type of load that maintains the same direction and degree of force during operation." = Tow vehicle and/or TrailManor at rest.
Dynamic Load - "A type of load that changes in the direction or degree of force during operation." = Tow vehicle and TrailManor in motion, springs and WDH load bars working within their normal limits.
Shock Load - "A type of load characterized by extreme speed and a tremendous amount of force." = Tow vehicle and TrailManor in motion, Springs, shocks and/or WDH load bars hitting a limit such as the TV rubber bump stop on the axle, a coil spring fully compressed or extended, or a shock fully compressed or extended. |
When I refer to "Shock-loading" in conjunction with the WDH, I am referring to when one goes over bumps and dips (I have commented on this regularly) the weight of the tongue of the trailer is lifted off of the trailer hitch by the upward thrust, then falls back down by the force of gravity, resulting in "Shock-loading" on the trailer frame and axle as well as the TV frame and axle when they "Bottom out". Like when one drops a bowling ball and it hits the ground.
The spring bars are designed to bend at a certain rate during the "Dynamic Load" and usually this load is not an issue unless the dynamic load is enough to cause the vehicle to bottom out due to over-loading. This over-loading and chance of bottoming out will be more severe with 1200# spring bars than with 600# spring bars.
When one uses spring bars that are far beyond the necessary rating needed, far more of the loading (of all types) is transferred to the trailer axle (via the trailer frame) then is necessary to accomplish the intent of the WDH. When this occurs, it is a negative as it may overload the trailer tires more than necessary and may cause tire damage.
On most pop-up trailers and some tow vehicles a WDH (of any kind) is not recommended because it can cause damage to the vehicle's structure. Common sense should tell one that if an owner were to use a 400# rated WDH hitch on one of these vehicles, they would stand 1/3 as much chance to cause damage than if they were to use a 1200# rated WDH for the same reasons that I have mentioned.
I never tried to discourage or even suggest that others not use a WDH. On the contrary. I go out f my way to encourage the use of them. They are definitely a safety tool. I just encourage people to explore the balance in using this device due the amount of tire failure that we seem to be having.
Can I prove that an over-rated WDH causes tire failure?...... NO!!!!!...... Common sense tells me that it
could contribute. If my addressing the issue "Scares" some...... that is not my intent. Maybe those that get "Scared" by the topic need to do a little more research.