Quote:
Originally Posted by Original Truckdude
Thanks Lakeroadster, you have done a lot of analysis on this. I am adding a receiver hitch in place of my rear cross member. I looked at your various c-notch stress studies and none seemed to match the CPP design. Any chance you can add one? I can send you the dimensions. I qualify as one of those who does not understand beam analysis. Dammit Jim, I'm a banker, not an engineer.
My goal is to keep the bed floor stock. There is about 1" of space between the frame and the bottom of the bed wood. Maybe welding two pieces of 1"x1" square tubing to the top of the frame will increase the vertical height? I do plan to weld the C-notch in place and possibly box the inside.
My truck will be multi-purpose, mostly cruising, hauling stuff from the lumber yard, maybe towing a car trailer or car, and the occasional vintage drag race.
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Please contact CPP. It's their design, they know the materials of construction, weld filler metals used and
they need to be the one to steer you guys in the right direction by informing their customers of the towing capacity, and do so in writing. If it isn't in writing, it isn't worth risking it.
I really don't want to get between site vendors and their customers. But I am looking out for you guys. These notches derate frame strength and the vendors should be telling you how much. To not do so is just plain dangerous, IMO.
As SlowBuild eluded to there is heavy duty notch available. If it is designed for towing what is its rated capacity? I haven't seen that stated anywhere.
This is serious business guys. If you hang a Class III hitch on your truck and load it up to it's rated capacity what will happen? FEA, Finite Element Analysis is one way of trying to determine "what will happen"
Here is a generic FEA performed on a notch that is similar in design geometry to the one being discussed above. See the slide bar on the side, it denotes Safety Factor based on a given load.- Stock Frame = 1.72 Safety Factor
- Notched frame = 0.327 Safety Factor
The generic notch FEA reveals the frame has 19% of its original strength.
Stock Frame = 1.72 Safety Factor
Notched frame = 0.327 Safety Factor
