Other added benefits a lot of times. You can stuff some really wide, cushy tires on there. I just did this with an '85 Raleigh and 700 x 38 clear with plenty of room. Here again though brake caliper can restrict what you can do. Also, if you are friction shifting then you can use a wheel with a freehub and cassette option a lot of times. If the RD doesn't cover the full range then just use the limit screws to lock out a cog or two. This frees up a lot of options for you though and a lot of times a modern cassette will just shift better than an old, non-stepped freewheel.