Indexing is a particularly stupid idea on front shifters. I have SunTour ratchet thumb shifters on my mountain bike. The front is blessedly nonindexed, to allow cage position feathering, and I always run the rear in non-index mode, which let me easily upgrade from 7 speeds to 8. I was having trouble with the front/left shifter, which began to require an inordinate amount of force if tightened enough to prevent slippage. The problem was that I had worn out the ratchet mechanism; a new shift lever solved the problem. Yes, above-bar thumb shifters are the way to go.
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"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069