JD X300 deck belt question

I have a JD X300 lawn tractor with a 42" side discharge deck. It uses a deck belt 1/2" wide. I beat it pretty hard sometimes almost using the machine like a brush cutter. I'm continually breaking and/or kicking belts off. If I can find a 5/8" belt, of the proper length (144"), does anyone think this might give me better service? I've checked the pulleys and they appear wide enough to accommodate the wider belt.
Any thoughts or help here will be appreciated. Thanks.