Originally Posted by
Dirtdrop
This question comes up about once a month. It works great for me. Sheldon Brown says it will work, too. If you compare a 7 speed and an 8 speed cassette side by side, you'll see that the difference in spacing is minute. Modern Shimano derailers can handle it easily. You can also use 7 speed shifters with 8 speed cassettes.
I agree and I disagree.
I've tried various combinations of 7-speed and 8-speed shifters and cassettes over the years. I've never been able to get them to index reliably to my satisfaction. I cen get them to work - kind of, just not to my satisfaction. The people who tell you that it works great are either better bike tuners than I am or they aren't as picky as I am.