We have been towing a very light tow trailer (3,800 pounds fully loaded) with our ML 350, and now want to move up to a larger trailer. I know the tow capacity is 5,000 pounds, but does anyone know how close to that weight you can come, without affecting performance? I am told by RV dealers that we should leave at least 500 pounds available - is this true? So, for example, if we are looking at a new trailer for which the empty (shipping) weight is 4,100 pounds, and we add an estimated 500 pounds on for solar, propane, screen room, and etc., that puts us at 4,600 pounds. Is this okay? Also, the hitch weight is 350. Does anyone know what the maximum hitch weight is for the ML 350, and/or is this the same as the maximum "tongue weight?" And, what is the maximum tongue weight anyway? Our dealer is useless with regard to obtaining this information.
Thanks for any knowledgeable response.

 

This should give you all the info that you are looking for: http://www.whnet.com/4x4/towing.html
Is your hitch OEM Oris with frame L-brackets installed?
Are there brakes on your new trailer?
Bernard