I have had problems with the fit of the aluminum spacers. On the two I have the anodized coating is on the inside too, and it is thick enough to cause an interference fit. I've had to heat them up and/or pound them on to get them installed. On one of them I tried to turn the ID a bit larger on my lathe, but that coating is hard and didn't cut very consistently. Still got it to work, but it was a lot of screwing around that I've never had to do with a stock spacer.
