Given that you didn't have an ellipse guide for this, I'm going to take that into account when it comes to my critique of your construction. That said, I really can't stress this enough - an ellipse guide, even the more limited master ellipse templates (which is what most students end up getting, given that they're a LOT cheaper than a full set, though limited to smaller sizes) would have made this challenge a lot easier and a lot more valuable, while also being of great use into the next lesson (specifically when we use smaller ellipses to help us build unit grids).

So, if you're having trouble finding an ellipse guide, let me know what country you live in or what kinds of online stores you have access to, and I'll see if I can find something that helps.

Anyway! Starting with the construction aspect of this challenge, I can see that you had quite a bit of trouble when it comes to actually controlling your larger ellipses (this is one case where drawing them smaller probably would have helped with that), but I can see a general sense especially towards the end that you're shifting your ellipses' degrees slightly wider as you move to the opposite side of the wheels, and you're incorporating a slight, but present, bulge through the midsection to help achieve more of an "inflated" appearance. This probably could have been emphasized a little more (although that depends based on your reference images), but as a whole, it's moving in the right direction.

Similarly, your construction of your rims do appear to show attention being paid not only to the front face of the structure, but also the side planes of each spoke to ensure that they feel three dimensional.

The only real failing here was the linework - and while the ellipses are completely understandable, the problem is that in having loose ellipses, it trickled down into the rest of your linework as well. As we can see here you've got a ton of chicken scratching. It's not that you don't know better, but that the loose ellipses put your brain in a different frame of mind, making everything sketchy regardless of whether you knew how to do better. And that is one of the major reasons why an ellipse guide is invaluable here, and in its absence, you cannot expect to complete the challenge in a similar timeframe. It's going to take that much time to apply the ghosting method, and to hold to the markmaking principles from Lesson 1, and to keep holding to them even as the structure as a whole suffers from the looser ellipses.

Continuing onto the other side of this challenge, unfortunately you've fallen a bit of an intentional trap. Given how far removed we are from Lesson 2 at this point, it's unpleasantly common that students tend to forget that the principles of textural markmaking and implicit markmaking seem to drift away like something of a bad dream. But, as a tire tread is basically just a bunch of forms arranged along the surface of a cylindrical structure, it very much falls into the realm of texture.

Looking at drawings like this one, visually it looks fine. And it is fine, because it's floating in the void on its own. But when you take that wheel and squish it into the drawing of an actual car, all of a sudden things change. All of those marks making up the tread create a lot of contrast squeezed into a small space. And so, it creates a focal point in the drawing, pulling the viewer's eye to the wheels whether you want them to or not, because each textural form was conveyed using outlines (explicit markmaking).

For the most part I'm going to leave you to review the Lesson 2 texture material, but I do want to share this example. It's decidedly not a tire (it's the scales of an african bush viper), but it's not dissimilar, and most importantly the example shows that we can use more ink, or less ink, and as long as we're working implicitly by only drawing the shadows those forms cast, we can make as many marks or as few marks as we wish (within reasonable limits) without changing the nature of the texture being described. And so we don't have to choose between conveying the tire tread or not - we can include that information without necessarily having it all laid out in full detail.

Additionally, when it comes to tires with shallower grooves, it's easy to end up focusing on those grooves, when in fact the actual forms that make up the texture are the walls and floor of the grooves, not the empty space itself. To that point, here's a diagram about tackling holes in textures.

Now, admittedly while the texture issue would have been present, I do expect that you would have knocked this one out of the park, had you an ellipse guide, and it is unfortunate that you didn't. But, all the same, I'll leave you with this critique and mark this challenge as complete.