text: film between the tire and the runway. 
  In this 
  case, the peak coefficient of friction 
  rarely 
  In some extreme conditions, the 
  exceeds 0.3. 
  tire may simply plane along the water without 
  contact of the runway and the coefficient of 
  than 0.3. Smooth, 
  friction 
  clear ice on the runway will cause extremely 
  low values for the coefficient of friction. 
  In 
  such a condition, 
  the peak value for the co- 
  efhcient of friction may be on the order of 0.2 
  or 0.15. 
  
  When the runway surface is dry, brush- 
  finished concrete, the maximum value for the 
  coefficient of friction for most aircraft tires is 
  on the order of 0.6 to 0.8. Many factors can 
  determine small differences in this peak value 
  of friction coefhcient for dry surface conditions. 
  For example, a soft gum rubber composition 
  can develop a very high value of coefficient of 
  friction but only for low values of surface 
  shearing stress. At high values of surface 
  shearing stress, the soft gum rubber will shear 
  or scrub off before high values of friction co- 
  efficient are developed. The higher strength 
  compounds used in the production of aircraft 
  tires produce greater resistance to surface shear 
  and scrubbing but the harder rubber has lower 
  friction coeflicient. Since the high 
  intrinsic 
  performance airplane cannot afford the luxury 
  of excessive tire weight or size, the majority 
  of airplane tires will be of relatively hard 
  rubber and will operate at or near the rated 
  load capacities. As a result, there will be 
  little difference between the peak values of 
  friction coefficient for the dry, hard surface 
  runway for the majority of aircraft tires. 
  
  is much lower 
  
  Note that 