One thing I learned with my 07200023 belt is that once a belt rolls onto its side, I don't keep using it even if it still looks okay. I had much better results replacing it and then making sure the idler arm moved smoothly before installing the new one. Since then it's been tracking normally.
That's exactly why I keep a spare deck belt on the shelf. I use a 07200023 belt, and even though mine has been holding up well, I'd rather have a replacement ready than lose a weekend waiting for parts. If a belt fails that quickly on a brand-new mower, I'd definitely push for a warranty...
I had a similar issue with my Craftsman and replacing the worn 130969 belt made a noticeable difference. If your old belt has stretched, it's definitely worth replacing before chasing bigger problems. I used this replacement -...
I replaced my 07200023 deck belt earlier this season, and while I was under the mower I also checked the idler arm and tension spring. Even if the spring is the failed part, it's worth making sure the idler pivots freely and the pulleys spin smoothly before putting everything back together. It...