Here's a device that makes it possible to instantly know the tongue weight of your trailer-and avoid the danger of having too much or too little.
Ideally you would be able to measure tongue weight every time you connect the trailer—which is exactly what the Weigh Safe Drop Hitch is designed to do.
Your trailer should be loaded so that 10-12% of its weight is on the hitch and it can be extremely dangerous to tow with too much or too little weight. You risk losing grip on your front tires or losing the ability to handle your vehicle as well--significantly increasing your risk of an accident.
Read the rest of David Frane's review of the Weigh Safe Drop Hitch.