Hi there,
apparently I cannot bend the curve in the way it is presented in your tutorial. If I chose the X axis (instead of Z) it shows the tire somewhat inverted (the outer rim is presented as the inner ring and the open sides are pointing outward). I checked the normals but cannot find out why it doesn't behave like in your tutorial. I seem to have positioned everything the way you did (along the same axes).. Any ideas or how I can swap that? "Deform Axis" to "-X" doesn't do the trick..
problem solved - I just swapped the direction of the last extrusion (that creates the depth of the tire). Now it points in the opposite direction (not towards the reference image but the other way). This apparently solves it perfectly. It's somehow different from your tutorial (still on the X axis), though. Maybe because I use the most recent version of Blender?
I don't know if this is the problem or not, because I haven't gone thru this course yet, but sometimes the position of the mouse cursor in relation to the selected when you start an operation affects the results.
This is definitely a constant hassle I even still face, haha.
We have two factors competing with each other here: The rotation of the mesh (tire tread), and the tilt of the curve.
In this instance, something you could also consider doing (especially if you like how you had the tire tread mesh laid out to continue to tweak it easily) is to actually alter the "tilt" of the curve instead. You can do this by selecting a handle and pressing Ctrl + T, or by using the slider in the side panel under Item. You'll have to make sure that you have the curve actually tiling the mesh as you intend it first, so picking the appropriate Deform Axis in the modifier is important, however if you find that it is just flipped you can simply turn the curve's tilt 180 degrees to achieve the same result, while also preserving the how you've set up your initial mesh to continue modeling. :)
