I used to too, but was severely chastised for it on the 41. I now see the light. You want as new a tire as possible on the front for good steering and best protection against possibly catastrophic front flats. Moving front to back and putting on a new front gets just as much wear from your tires, but it is safer. The only problem is if you like your tires to match AND want to change what tires you are using. I have never had that problem. I do like them to match, but am not changing from the 4000s.