I got the mower stands a few months ago, and I got a JD rider a few months back, so I popped mine off for the first time, since I knew it would be off a while.
I just took the right pulley cover off, and pushed on the idler with one hand and rolled the belt off the right pulley with the other. I am not a strong person in my opinion, so maybe I just got lucky.
I am not certain why they recommend taking it off, but I will submit this so that maybe more knowledgeable mechanical folks might correct me, and we will have our answer.
I thought it was so you could lightly grease the shiny parts of the pulleys that the belt keeps polished so that it would not rust in the off season, and possibly over the years, pit the pulley where the belt runs, making a surface eventually that would tend to gnaw on the belt as it runs.
I popped mine off because I didn't want to risk the belt somehow "taking a set" in that position, and thought I was committing a cop-out by not putting a protectant on the pulley face.
It is a cop-out I plan to studiously continue, but the way. It is in a garage, on it's new axles, and in plain sight, so I thought instead, I would simply watch out for rust, and if it happens, arrest it immediately.
There is a process called brinnelling that I will leave to each of you to look up on your own.
Brinelling - Wikipedia, the free encyclopedia
I never have understood when it is likely to happen, and when it is unlikely. But if someone wishes to offer an opinion on that as a possibility, I would appreciate reading it. If no one does, my opinion per the definition on Wikipedia is that it is unlikely.
The source of my confusion is the idea of rotating the shafts of motors in storage for fear of the bearings will fail just sitting there. I may have fallen for a myth so where along the way. But I rotate the shaft on my PTO generator whenever I think about it. At work as I pass a motor in storage, if I am not in a hurry, I rotate the shaft. So, if it is a myth, I am superstitious.