I am replacing the front (drive) wheels on my craftsman mower about every 6 months because the teeth on the inside of the wheels get all chewed up. I have a fairly level yard and mow it once a week in growing season. All else seems to work fine on the mower, but at $40 a pair this is getting expensive. Any suggestions on mowing technique or mower adjustment that can extent the life of these front wheels? Do other front wheel drive mowers have the same problem? Thanks for your insights. Steve