Sam asked:
I am curious on pre war track style bikes I have seen both half inch pitch and inch pitch. Is there a date that one was in favor over another? Where they both used at the same time on high end bikes or were better bikes one or the other? ______________
There is enormous time overlap between half inch and inch pitch chains. It is also worthwile to consider both block and roller inch pitch chains. Block chains are the earliest type and are simply a piece of steel which engages the chainwheel teeth and two side plates for each chain section. On some industrial chain the block is laminated rather than solid. Roller chain was invented around the turn of the past century by the British firm of Renold which still makes industrial chain today and stopped making bicycle chains sometime in the 1970's I guess. A roller chain provides a bearing to allow a rolling rather than sliding action as the chain engages the tooth.
I have seen literature showing 1/2" roller chain options on bikes as early as 1905. But displacement of block and roller 1" pitch chains was gradual and took a long time. Track racers are extremely conservative and were the last holdout. I have a 1930's Sieber track bike with 1/2" chainwheel and chain which I suppose is original and I had a 1959 Frejus track bike with original 1" pitch Campagnolo Record and a Regina block chain. So if I had to say what was typical for a track racer in the US: 1895 to WWII 1" block chain, 1950's 1" roller chain and 1/2" roller chain from 1960 on.
So from 1930 on the change is gradual and determined by individual choice or availability. At the end block chain was only available for expensive racing machines. I tried to find industrial sources for block chain and it is very expensive today as it is considered archaic and chain must be made in volume to be economically feasible.
Joe Bender-Zanoni