Rolling friction of a hard cylinder on a viscous plane
  The resistance against rolling of a rigid cylinder on a flat viscous surface is investigated. We found that the rolling-friction coefficient reveals strongly non-linear dependence on the cylinder's velocity. For low velocity the rolling-friction coefficient rises with velocity due to increasing deformation rate of the surface. For larger velocity, however, it decreases with velocity according to decreasing contact area and deformation of the surface. 
Thorsten Poeschel, Thomas Schwager, and Nikolai V. Brilliantov