Originally Posted by
HillRider
If the current chain and cassette have significant mileage, a new chain may skip badly on the old cassette, particularly on the cogs you use the most. Plan on replacing the cassette too.
This very thing happened to a 1991 bike I am rebuilding. I asked on BikeForums what could be causing the skipping and this is the same answer I got. Changed the cassette and all was good.