In reading some of the posts on the forum I noticed a few mowers that had their idler spring break or come off. I have not had any problem with mine on my 60 inch Hustler Raptor SD. But figured if I did, I didn't want to have to take it to the dealer for warranty claim when I should be mowing. So, when I had the opportunity I stopped by and bought the spring so I will have one if I need it. Having a spare spring, mine may never fail (some law says that) but if it does, I can install it and carry on. Not trying to be a smart *** here, just planning ahead. It may be something to consider. Here is the part number for the idler spring that is used on the 60 inch. EX604291 I don't know if the same spring is used on all size decks but I would guess it is.