What is the difference between the John Deere S220 and S240?

Here is how the John Deere S220 and John Deere S240 compare on John Deere's published specifications:

• Wheelbase: John Deere S220 48.9 in. vs John Deere S240 48.9 in.
• Cutting width: John Deere S220 42 in. vs John Deere S240 48 in.