Not sure how correct the web site below is, but is it possible that they have a different capacity because of different safely standards between the US and the EU.
Weight Information
Gross Axle Wt Rating - Front (lbs) 3650
Gross Combined Wt Rating (lbs) 7800
Curb Weight - Rear (lbs) 1855
Gross Axle Wt Rating - Rear (lbs) 3800
Gross Vehicle Weight Rating Cap (lbs) 6400
Curb Weight - Front (lbs) 2615
Suspension
Stabilizer Bar Diameter - Front (in) - TBD -
Suspension Type - Front Wide Track
Axle Type - Rear Semi-Floating
Shock Absorber Diameter - Front (mm) 31.8
Spring Capacity - Rear (lbs) 3900
Axle Ratio (:1) - Front NA
Stabilizer Bar Diameter - Rear (in) NA
Suspension Type - Rear Leaf Spring
Axle Capacity - Front (lbs) 3650
Shock Absorber Diameter - Rear (mm) 31.8
Axle Type - Front NA
Axle Ratio (:1) - Rear 3.21
Spring Capacity - Front (lbs) 3650
Axle Capacity - Rear (lbs) 3900
Trailering
Dead Weight Hitch - Max Trailer Wt. (lbs) 5000
Fifth Wheel Hitch - Max Tongue Wt. (lbs) NA
Wt Distributing Hitch - Max Tongue Wt. (lbs) 700
Dead Weight Hitch - Max Tongue Wt. (lbs) 500
Fifth Wheel Hitch - Max Trailer Wt. (lbs) NA
Wt Distributing Hitch - Max Trailer Wt. (lbs) 10,000
1998 Dodge Ram Specifications