I own a Craftsman 917376661 walk behind lawn mower. I've had to replace one of the rear wheels three times in the last three years (part number 194231X427). The wheels are plastic and they are cracking around the base where the shaft inserts. Other than that it's a good machine. Could someone recommend SOMETHING that would help me? Could I buy a different wheel that isn't so cheap? A metal wheel? Maybe modify a new wheel to strengthen it up so it doesn't crack and fall off?