The size of BCS tractor wheels are very important: they can dictate whether an attachment can be operated by a particular tractor or not. Larger wheels give tractors more height, thus increasing the versatility of the tractor. For example, 4'' x 8'' wheels come standard on models 718 and 620, but to operate the Brush Mower, 5'' x 10'' wheels must be installed to heighten the mower deck and operate effectively. Wheel sizes can also dictate the wheelbase width. See this article for more information. Pneumatic standard wheel pairs come in the following sizes: 4'' x 8'' (part # 92243680) Standard on models 710 and 718. 4'' x 10'' (part # 92248332) Standard on model 722. 5'' x 10'' (part # 92248334) Standard on models 732 and 739. 5'' x 12'' (part # 92244809) Standard on models 749, 852, and 853. 6.5'' x 12'' (part # 92244806) Standard on model 750.