Jumping right into the structural aspect of the wheels, you're doing a great job with the core body. I'm quite pleased to see that you're paying a fair bit of attention to defining the middle with larger ellipses, allowing for a curving profile that helps us understand the wheel as something inflated, something that would land with a bounce rather than a heavy thud.

When it comes to the spokes/rims on each wheel, your linework here is a little rough, and probably would benefit from a little more time to ensure that each mark is still executed with care. As it's a smaller, tighter space, this can make us more prone to putting marks down sloppily, and forgetting concepts like the three stages of the ghosting method, which in turn will result in forms that simply don't feel as solid as they could. The solution is, as always, more time to ensure that you don't skip over anything. As a side point, I noticed that in number 7 you neglected to draw the side planes, and only drew the outward face.

One other point I noticed in a couple cases is that when drawing the side plane of those spokes, you extended the far edge as far as the edge closer to the viewer, causing that plane to go right through the inner tube of the rim, where it should have been cut off as shown here.

The other aspect of this challenge - that is, capturing the texture of the tire tread - is something of a trap. Being as far removed from Lesson 2 as we are, it's very common for students to forget the principles of implicit markmaking - that is, drawing cast shadows to imply the presence of the forms that cast them, rather than drawing them directly. Generally students will end up tackling the problem in whatever manner feels natural to them, rather than reviewing the material related to the concept. In highlighting this, we can stress the importance of going back and reviewing content we may have forgotten.

Looking at your work, it does appear that you've fallen into that trap. While that's not something to really worry about - most students do - it does mean that there are concepts from earlier in the course that you've forgotten about, so let's talk about it. When capturing these tire tread structures, it appears that for the most part you're drawing what you see directly. That is to say, you see shapes or lines in your reference image, so you draw those shapes or lines on your page. What this neglects however is the step of understanding the forms those shapes and lines represent in 3D space. It's that understanding (as explained here in Lesson 2) which is meant to help us make the decisions in terms of which marks we put down. More specifically, it helps us design the shape of each individual shadow we draw. This is very important, because it's the design of that shadow shape which dictates the relationship between the form casting the shadow and the surface receiving it. Thus the only way to successfully draw the shadow correctly is to consider that spatial relationship, to understand what the reference image is showing us rather than simply replicating it on a visual level.

I will note that even when a student is actively attempting to do that, it's generally easier to think about the big "chunks" that make up the tire's tread. When we deal with tires with shallow grooves instead, we can much more easily fall back into thinking about the grooves themselves as though they're the textural forms we're supposed to be focusing on. After all, if we had to name the kind of texture, we'd describe them as "grooves" - but grooves refers specifically not to the textural forms at play, but to the empty spaces between them. Instead, we need to be focusing on the walls that surround these empty spaces, and considering how they cast shadows upon one another. This diagram goes into this a bit further.

When we deal with these shallower groove textures, the end result might not even end up being that different between drawing lines directly (copying them from the reference) versus drawing the shadows they cast upon one another. It's still important though, as this course focuses on how we think about the things we draw, rewiring this in our brains - so even though the difference is minimal, it's still important to get in the habit of considering how these forms exist in space, and how they interact with one another.

Now, as the issue is a common problem that the exercise is designed to bring to the student's attention, it's not something I hold students back over. Instead, I simply ask that you go back over the texture material from Lesson 2 (starting with the reminders I linked some paragraphs up), and that you also consider what other concepts you may have left behind in a similar manner, so you can review them before continuing onto the last lesson. This includes things that would have been mentioned in feedback you've received.