Use the actual vehicle documents
Enable the towing-vehicle section in the Witmar configurator. The silhouette is schematic and power is informational. Neither supplies towing limits. Prepare the registration, vehicle and towbar documents. The Polish Ministry of Infrastructure explains the registration fields.
Enter distinct limits
O.1 concerns braked trailer capacity, O.2 unbraked capacity, F.2 vehicle GVW and F.3 combination GVW. Enter planned vehicle weight with people and luggage separately, plus the planned nose load. Compare limits for the vehicle, towbar and the selected trailer coupling. Blank fields remain unknown.
Choose a planning mode
Full-GVW mode conservatively compares the declared limits of both vehicles. With it disabled, the calculation uses planned actual weights. An arithmetic example: 600 kg trailer plus 1400 kg cargo equals 2000 kg; with a 2200 kg vehicle the combination is 4200 kg. These are illustrative figures, not a particular car's specification.
Avoid counting nose load twice
Nose load affects the towing vehicle's available capacity. It is not added again to the combined weight of the whole trailer and vehicle. Unknown trailer tare or brake type requires checking. Compare relevant transporters or light trailers.
Confirm the remaining requirements
This checks entered numbers, not driver entitlement or full road approval. Confirm coupling and brake specifications, manufacturer instructions and the requirements for your journey. Next, examine the transporter deck.