Originally Posted by rgwatkin
I would bet all the truck manufactures are closer to +25-50% of posted specs. They have to be with dynamic loads. The trick is no matter what your loads are don't hit holes/things at high speeds...just a good rule of thumb!
I can attest to Dodge/Ram, the axles are all rated at 3900lbs each. All Dodge Ram's are rated at 6500lbs GVWR, but the axles combined come in at 7800lbs, so that's 1000lbs of safety built in.
If you are running the stock 275/60R20 tire with the Goodyear Wrangler SR-A that Ram install's on it's truck, it has a max load of 2601lbs per tire, for 10404lbs; derated that's 9467lbs rating for the truck when aired to 44PSI per manufactures recommendations.
Folks who talk about damaging the suspension are not car or truck people and are usually talking sideways out their behinds.
Since the OP had a Ram truck and was concerned about 300# pounds, I am putting out there despite the payload police that you are not endanger of dying, or having a run away vehicle that will put everyone on the road at risk. Your axles are not going to break or bend and your tires won't explode. The truck will not be a death trap.
Now, that isn't a license to put a golf cart in the bed plus hook up the Airstream and go drive the Ike Gauntlet.