How over engineered are receivers?

rerod wrote:
The PO told me not to worry about the rusty receiver.. He said he pulled 10k for allot of miles. The Uhaul sticker was faded, but I now see its rated for 10k gross and 1000 lb tongue..

My gross is well under at 8k, but my tongue weight is at least 1250 lbs even relocating things back behind the axles.

I know receivers must be over engineered and mine should easily handle the additional 300 lbs tongue weight.. But I was wondering how much abuse these receivers can actually handle before failure. To me, the weak points are the six budget bolts holding it on.. I have better fine thread bolts, which Dexter used to attach my 5200 lb TT axle on before I lifted it 4". I could drill out the old holes and replace, at least the back two. Welding it on would also be a option.

Anyone have some first hand experience pushing receivers well past their limits? Iv seen people pulling hay wagons twice the rated limit, but that's not tongue weight or highway speeds.

rerod, you must keep in mind when asking questions about ratings on any of these forums, that, to many people in the RV community, ratings are ABSOLUTE NEVER-TO-BE-EXCEEDED LIMITS! In fact, there are quite a few who firmly hold to the "80% Rule". Nobody seems to know where that rule came from, but many hold it to be a self-evident truth, that one must never load anything to more than 80% of the manufacturer's RATING!
When we had horses, I used to load 90 to 100 hay bales, at 65 to 75 pounds each, on a trailer that had a Gross Weight Rating of 7000 lbs, hooked to a Dodge 3500 dually with 35 bales on it. Nothing broke. Come to think of it, I have no idea what the weight rating on the truck receiver was.
I towed a 32 foot fifth wheel with the same truck, at a total combined weight of 21,180 lbs. The GCWR of the truck in 1994 was 18,000 lbs. Nothing bent or broke.
I also at one time carried an 11.5 foot self-contained cabover camper on that truck, and towed my Jeep with a 41 inch extension in the receiver. Again, nothing bent or broke.
The bottom line is, none of us can or will give you permission to exceed your ratings. It is entirely up to you to make that decision.
Good luck.