Yep, in my experience with my GMC dually the upper Stableloads took away 2" rear sag, but made ride softer & tippy'er feeling..Riding on overloads definately is putting load on softer springs. Sometimes driving over ruts now will set camper to rocking even after I have stopped dead. Drove a season before adding upper Stableloads and truck was rock solid. Previously on my single wheel trucks I always used Timbrens and really liked the stability they gave. Timbrens put truck frame in direct contact with rear axle so really steady up any roll on corners etc.
