Before I start, a quick point about the ellipse guide. At the end of my Lesson 6 critique, I said the following:

Again, if you can get your hands on an ellipse guide for the next two lessons, it would be worthwhile. Full ellipse guide sets can be very expensive, but most students at this stage just pick up a "master template", which contains a range of different degrees but limited to a smaller size. A single master template is much cheaper than a full set.

You must have misunderstood - the "Master Template" I mentioned is a single template that covers the full range of degrees, but at a smaller size. It's a bit tricky to work with but still well worth it, and can be used on its own. It's a much more affordable alternative to getting a full set. This one is listed on our recommendations page. Like I said before, working with an ellipse guide is absolutely worth it, especially since your ellipses, while coming along, are still at a point where they may serve to distract you from what the lesson is focusing on.

So, to that point I won't discuss your ellipses - we know that they're a bit loose and rough, but there's no sense on dwelling on them beyond that.

When it comes to the tire treads, I think you did a great job of laying them out on the tire's surfaces. You also did a pretty good job of identifying where more ellipses were required to cover the more subtle bevels in the wheels' overall structure. You didn't just work with a simple cylinder, but laid out intermediary ellipses in a variety of places.

One area where your approach wasn't ideal comes down to how you tackled the textural aspects of the tire treads. So where you've got the big chunky treads, for instance, and even the narrower grooves. Specifically, you sought to outline each one in its entirety, rather than employing the concepts covered back in Lesson 2. Basically, when you've got these kinds of forms that adhere to another surface, you don't apply constructional techniques to them. Constructing them would be an example of explicit drawing, where you're drawing the form itself and defining all of its bounds. Implicit drawing is more appropriate here - that means drawing around the form and implying its presence in the negative spaces in between. We do this by drawing the shadows that form would cast on its surrounding surfaces. It allows for a much less distracting result with less linework and more reliance on larger forms. Be sure to review the texture section in Lesson 2, as it goes over this in considerable depth.

It's fair to mention that I did see you start to shift into that kind of approach with your bicycle tire, though this is also a case where your usual structured, specific approach to laying out the largely geometric patterns fell away to somewhat more random placement of "scales". Tires are manufactured, so they're always going to follow a very distinct pattern. It also means that the tire tread on a bicycle, being as small and tight as it is, would be a massive pain to capture. Of course, if you select a certain subject matter, you do need to be willing to see it through. Fortunately textural techniques like implicit drawing and relying on cast shadows give us far more control over transitioning from small areas of dense texture to much sparser texture elsewhere, so it can save us some grief when applied correctly.

So! You do have a number of areas to work on, and you definitely need to get your ellipses sorted. Either pick up a master ellipse template, or work a lot on tightening up your ellipses and improving your control with them. Regardless, you should still be doing the old exercises from lessons 1 and 2 as part of your regular warmup routine which ought to be refining those skills - so if you've been skimping on them of late, make sure you get back on the wagon.

I'll go ahead and mark this challenge as complete, so feel free to move onto lesson 7.