Tutorial, modeling a tyre.
3. The Sidewall
For the sidewall, make a pipe, aligned at the origin, in the front view. It doesn’t really matter what number you choose for the ‘Subdivision axis’, I chose 30.
Adjust the ‘Radius’ and ‘Thickness’ to match the reference. It should overlap the tread a little bit.
Select all but the front facing polygons and delete them.
Use the ‘Insert Edge Loop’ to add edge loops at appropriate places.
Using the guides you drew earlier as a guide, drag the edge loops into the correct position.
Extrude out a lip around the outside.
Add edge loops close together where you need a more defined edge. Press the ‘3’ key to smooth the mesh.
Duplicate the sidewall and give it a scale of -1 on the z axis. Reposition the tyre on the other side to fit the tread.
Now, if you’re completely happy with the tyre tread, select all the tread segments, go to ‘Mesh’ > ‘Combine’ and then ‘Edit Mesh’ > ‘Merge’. If you held down ‘V’ earlier to snap the vertices together, all the correct vertices should now merge together. It is worth inspecting the model for merging errors and adjusting the merge distance if necessary.
And there you have it, a complete tyre. If you think you’ll need more detail, you can alway add more edge loops etc. If you think you’re going to get really close, you could add edge loops for all the hard edges and smooth the result. Keep in mind, though, that this can make the scene very dense.