Mercedes ML 320 instability

Dicken Vicken
Dicken Vicken Forum Participant Posts: 8
edited November 2013 in Towcars & Towing #1

Having towed thousands of miles home and abroad with ml270 without the slightest wobble have uprated to ML320 and find it to be frighteningly unstable around 60 mph when passing lorries or being overtaken.I have experimented with different tyre pressures
and noseweights to no avail. I tow a Swift Conqueror 645 plated at 1900kgs but only loaded to 1750 . Well within 85% rule.Can anyone advise.