I don't know if the wheel that you're talking about is this one.
This photo is from my hamster's old cage. He was on a cage with bars and I had to remove the stand. As others have said, it's hard because you really have to pull hard do disassemble it. Once it's done, you have to push the back of the wheel between the bars. Obviously you have to do it with the piece that protudes horizontally. I have a 1 cm bar cage and it was hard, I don't know If It will be possibly to attach on a smaller space. I have to push and push til I was able to attach it. When you're attaching it, it bends the bars, but once it's on the correct place it fits perfectly, then you just have to move the piece to on side, leaving it vertically, and it's done.
I don't know If I explained it well.