Originally Posted by
El Aurens
This seems to be the cause of endless discussions, many freewheels tossed on the trash heap, and countless hours spent adjusting derailers. One possible simple cause should always be checked first.
The situation you recommend to check first is by far the least likely cause of skipping. In over 20 years of working on bikes there were very, very few instances where a 1/8" chain was installed - maybe 1-2. It is however possible for a similar incompatibility to occur when an old chain designed for a 5 speed freewheel is used on a much higher count rear cassette. In addition the solution you describe will not guarantee that "your problems will disappear."