So before we get into the critique, I think there are elements of your general outlook that are getting in your way somewhat. First off, if I understand this correctly; you're using A3 paper, and therefore any ellipse guide you use will need to be pretty big, and therefore finding such an ellipse guide would be prohibitively difficult, expensive, or both. As a result of this, you've been forced to freehand your ellipses, which adds an additional element of difficulty to the exercise, and takes some of your cognitive capacity away from the main task upon which we want to focus. This happens - not everyone can get ellipse guides, and while master templates are available at a decent price (and are what most people use for this course), they're not terribly flexible and only offer a very limited range with rather small ellipses.

There is obviously a simple solution to this - draw your wheels on A4 paper, and work within the limitations of a master ellipse template. This would allow you to focus on the core of the exercise and to gain more from it overall. The ellipse guide would continue to serve you through Lesson 7, and while you may not use it after that, helping you gain more from these last few sections of the course would still be worth its price.

Anyway, that's a choice you made, and I leave that up to you. Hopefully I have offered a different way of looking at the situation.

So, looking at your wheels, there are definitely some constructions that are quite successful - for example, this one came out very nicely, both in terms of capturing the complex tire tread (and wrapping it very nicely around the cylinder) as well as with the overall construction. The cylindrical form is well established despite being freehanded, and the rim itself is very well built.

There are plenty of other cases that aren't as well done, however. As you noted yourself, the use of hatching lines isn't really in line with what we should be doing here in the drawabox course, but it's less of an issue in the piece I linked above. Where it really becomes a notable problem is where you mix it with areas of solid black (either drawn with a brush pen or filled in with a fineliner). It's important to be consistent.

When it comes to capturing complex details, I think there's an element you did a really good job with - specifically actually getting the repeating elements down. Where they didn't come out too well however is in how you actually went about capturing the illusion of texture/detail. Back at the beginning of February, I overhauled the section on texture from Lesson 2. What's explained there now is still the same as what was explained beforehand, but I made an attempt to go about it differently, with short videos on each individual concept. I strongly encourage you to visit it again, because there's one major issue in how you're approaching your texture/detail: you're outlining everything.

These tire treads are made up of textural forms that are bound to the surface of a larger form. Therefore, as explained in Lesson 2, we no longer approach them through explicit constructional means - with outlines defining each individual form - and instead shift to implicit techniques, specifically drawing the shadows these forms cast, instead of their outlines. This is explained here. That means not drawing any of the outlines or the internal lines that may exist within a given textural form. Just drawing the shadow it casts on its surroundings.

Now this is where we generally end up using those bolder, filled shadow shapes - but it's important to understand that we're not filling in the gaps between forms, as you've done in cases like this. They're still shadows, which means the filled black shapes have a direct relationship with the form casting them, not with the negative space between them.

Keep this in mind as you continue to move forwards. I am going to mark this challenge as complete, but I do strongly encourage you to get an ellipse guide as it will help you considerably with a lot of the complicated matters used in lesson 7.