Most of them with scissor lifts will lift about a ton more than they are rated at. The biggest deal is do you have enough battery (heavier payload takes more power) and if is it loaded properly.
My Diamond C uses a six inch cylinder scissor lift (most use five inch). It has failed three times to lift the load enough to get it out. The first time the solenoid on the hydraulic pump crapped out. This was before I’d had the trailer a month. New solenoid and the second has never been a problem. The other two times were both slightly overweight, but the problem was it was all loaded in the front half of my 16’ trailer. The loader operator at the killings plant doesn’t understand trailers and always loads at the headboard. Good, for dump trucks trying to spread the load, bad for trailers, it doesn’t spread the load. Compounding the issue, where I was dumping it, the front of the trailer tongue is down I. The valley between my driveway and the street.
My trailer holds right at 5 tons, while staying legal. GVWR of 14,900. Trailer weight around 5,000 pounds, empty. It’s a 16’, which is rated the same as the 14’ trailers, but allows less payload due to more trailer weight. Five tons of gravel leaves about a foot of floor open on each end of the pile (front and back). In the middle of the trailer, the pile will fill about 2/3rds of the 24” sidewalls. Where people get in trouble is filling them up with heavy product. With dirt or gravel, fully loading the physical space will be two to three times the rated payload capacity-most hoists and pumps will leave you shoveling this.
Dump trucks run off a PTO, off a large engine. This gives them a lot more power than a typical dump trailer will have.
A good option, if you’re worried about battery power, is to get one with a small engine on the tongue. You start the engine, which powers the pump. These are stronger, but now you have another engine to maintain.
