Making the Front Tire

Creating the rear wheel

I selected the tire and rim of the front wheel, held down shift and dragged a copy of those two pieces to the back tire.

I created a tube and roughly lined it up with the back rim, I then set the sides to 20. I then aligned the rim again so that the poly segments would be about the same size as the pieces of the rim that come out from the top. I then deleted the remaining polygons and added end caps to the open ends using border mode and cap.

I selected the top polygons on the ends and then used extrude to get the pieces that attach the rim to the tire. I then applied NURMS, and added some definition using the swift loop tool. Then I used align to align the rim to the tire and then scaled the rim so it sat inside the rim.