I would buy a sleeve. I did this when I bought a set of BB Infinite bearings for my new SC. The BB Infinites didn't come with a sleeve, so I had to buy a set of bearings from trek, about $50 I think, to get a sleeve since they didn't offer it separately. Not the end of the world, I now have a spare set of trek bearings for when the Infinites wear out. The sleeve should pretty much last forever.