In short, yes. The more the van weighs, the harder the brakes have to work to reduce speed or bring it to a halt. You'll also go through tyres much more quickly, with fully laden vans, but you should never exceed the vehicle’s weight limits. You can find a vehicle’s weight limits in the owner’s manual and they are usually detailed on a plate or sticker somewhere on the vehicle itself. This might be on the body behind the driver’s door, on the back of the fuel filler cap or in the engine bay, for example. It should also be possible to find out a trailer’s weight from its owner’s manual or on the trailer itself. Don't confuse gross vehicle weight (GVW) with the gross train weight (GTW): The GVW is the maximum permitted weight of the vehicle (plus any people and load it is carrying), while the GTW is the maximum permitted weight of the vehicle plus any trailer being towed and its respective load.