Regarding saddle mounting threads, all are standard clockwise-to-tighten. Left-hand threads are used only where necessary to keep rotating parts from self-disassembling, so we find them on the fixed BB cup (English/ISO and Swiss), the pedal eye of the left crank and mating pedal shaft, and the bearing cap of old-style freewheels.
My Brooks Pro sometimes creaks, but after 30 years and over 40K miles / 65K km, I suppose it is entitled to!
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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