Wheel size for the 2006 Smart Forfour will vary depending on model chosen, although keep in mind that many manufacturers offer alternate wheel sizes as options on many models. The wheel size available will alter the range of tyres available to be fitted.

Fuel consumption for the 2006 Smart Forfour is dependent on the type of engine, transmission, or model chosen. The Smart Forfour currently offers fuel consumption from 6.8L/100km.

The 2006 Smart Forfour has maximum towing capacity of 750kg. Some models also offer heavy-duty or towing option packs which can increase towing capacity, as well as options which can hamper towing capacity. Towing capacities can vary wildly on a large number of factors. These include engine, transmission, model, and options chosen. Always check with the manufacturer or in your vehicles handbook before attempting to tow anything.