  Since the time of the original Greenwood & Williamson paper, it was noticed
that abrasion and wear lead to possibly bimodal distribution of asperity height
distribution, with the upper tail of asperities following from the
characteristics of the process. Using a limit case solution due to Borucki for
the wear of an originally Gaussian distribution, it is shown here that the tail
is indeed always Gaussian, but with different equivalent parameters. Therefore,
if the wear process is light, one obtains a bimodal distribution and both may
affect the resulting contact mechanics behaviour. In this short note, we
illustrate just the main features of the problem. We conclude that it is an
oversimplification to consider surfaces Gaussian.
