I love these new designer LEGO sets, but I wish that all of their parts would be available in LEGO CAD! So... 1. Part 4264 (large steering wheel in CAD) should be the small grey steering wheels in the set. 2. The smaller wheels are used on the semi cab. The larger wheels are used on the trailer. Send me feedback! Jason ( jello_hd@hotmail.com ) Just make sure you mention LEGO in the subject so I don't miss it.