Last night I removed the DA cassette from my Ksyriums. The cassette came off, then there was a tiny metal spacer on the inside of the cassette body. I took that off, put my new SRAM cassette on. Problem was, when I tightened the lockring, it was not snug, and the cassette could move. So, I removed it, put that spacer back on the freehub, put the SRAM cassette back on, and it all seems good. Is it supposed to be there? Is that there so I could put a 10spd upgrade on at some point without replacing my wheels?