Silvio, have a look at this article
http://www.planeandpilotmag.com/cont...o_skylane.html
I regularly fly the 172RG and this is a great plane, however, as Piltdown Man implies, the undercarriage doesn't look like isn't designed for rough strips.
AFAIK, it's the same system (i.e. two rather spindly legs for the main wheels) on the Skylane.
HTH