I've had my Sport 42" for about a year. I noticed last year after a few cuts that you could see the tire tracks left from the mower. I just thought it was because my yard was newly sodded and it would go away after the grass thickened up. Well, It is doing the same thing this year. My neighbor borrowed my mower because he is in the market and that is the first thing he noticed after he cut his yard. He thought maybe there is a slow dripping gas leak that was getting on the tires and killing the grass in those areas, but I haven't found one. I wouldn't think that the weight of the mower would do this since I have seen hired people use much bigger mowers and this was not noticable. Is anyone else experiencing this or have any thoughts on what may be causing it? I will try to get some pics tomorrow after I mow.