You should be able to use the Tire Icon under the Forces Tab and then select the tire/roadusing initially one from the installation directory (atire) as in the picture.
Creating your own tire could be done if you have some partial technical info, using the tire fitting tool (ACAR)
You can place your tire files .tir .rdf in the working directory and call them from the Tire Icon in AVIEW. If you need to create the .tir or .rdf start by looking at the ones provided in the atire directory and will depend on the tire formulation
For roads you can use the 3d road builder tool and create a file
Danilo, graphic of tyre is not important, you need to choose tyre model (tir file), you have several options, from simple to to more advaced models like pac2002 or ftire. What you need are properies of you tyre, more advaced model more properties, vertical stiffnes always. In never versions of adams it is also possible to add graphic in tir file
You can't use a CAD file directly for the road. You need to convert it to one of the supported road formats. We are only using crg formats these days, but that requires that you download the (free) crg toolkit for Matlab and use that to convert the road data.
AS an alternative you can use the triangular rdf format. There are many examples on the shared acar.cdb that you can use to find out how that format works.
