I’m new in Blender. Can somebody help me with this: when I try to spin mesh (currently modelling tyre) in place of junction I get some strange faces and vertices (that look like as minor deformations) 
. Is there any way to solve this? Tnx
I do not know if this is your problem or not, but have you tried select all vertices (AKey), Editing (F9), Mesh Tools pane, Rem Doubles button?
When I make a circle for a tire, and spin the mesh around the axis by 360 degrees, at the start and stop point are two sets of vertices one on top of the other. This can make deformations.
Otherwise I do not know what the problem is. Can you please post a picture of the problem?
If you’re just spinning a mesh, not spin dupe, then you only need to select the leading edge of the mesh, not all the verts. As in make a triangle, select one side and spin 360 and you’ll get a circle. Spin extrudes one side of your mesh, if you have all verts selected, it’ll extrude them all on top of each other.
Spin dupe duplicates the whole mesh however many times in a circle.