Originally Posted by
GeoKrpan
I love downtube shifters. You can find indexed ones if you don't want friction.
The problem will be with the rear derailleur. If the OP is willing to fit a 7-speed freewheel, a narrower 7/8-speed chain and 7-speed indexed downtube or barcon shifters, he will also have to add an index compatible rear derailleur. Again, this is relatively expensive for someone without a parts stash and who will have to pay a dealer for the work.