Rubber GTs

[Simon.MATTHEWS@st.com]

     The increased load on the engine comes from increased rolling 
     resistance (as well as the extra energy required to accelerate) -- ie. 
     the amount of energy required to turn the tyres given the weight they 
     are carrying. When cruising below about 50mph, most of the gasoline 
     you use is devoted to this task!
     
     Rgds,
         Simon