You risk stress on tires and brakes, which can snowball into suspension and other mechanical issues, not to mention dangerous travel situations.
Unequal weight distribution is just as dangerous. Its possible to be within the proper total GVWR and GAWR ratings but still over-stress an axle. The weight must be balanced between all four axles, so that tires aren’t stressed, and the only way to be sure is to weigh each axle separately.
Despite these details, it really isn’t difficult to weigh your motor coach. The first step is to find a scale, preferable a CAT scale, where you can weigh wheel position, overall weight and axle load. It helps to keep a log, so that you have a reference of previous weigh-ins. This will help you track variances and diagnose the source of potential issues”especially if you have noted what was on board at the time.
Motor coaches are complex and sophisticated, but you can preserve yours by maintaining proper overall weight, inflating tires to specification and balancing the load. How much weight can you carry? The Recreational Vehicle Safety & Education Foundation suggests up to 8.3 pounds per gallon in water, 6 in gas, 6.6 in diesel fuel and 4.5 in propane.