Joined: Jan 2010
Posts: 9,808
Likes: 1,777
From: Northern California
Bikes: Cheltenham-Pedersen racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.
Three holes for the return spring?
It sounds like the cage pivot spring might be what you mean(?), or do you really mean the spring that resists the shift lever?
The choice of holes for either the B-pivot spring or the Cage pivot spring are the adjustment that can be made to adjust the position of the top pulley, to match the size of your chosen freewheel, and which can affect shifting response (a smaller "chain gap" gives a more responsive action at the lever).