Originally Posted by 3alarmer

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...Velobase is good, but for sheer wealth of information on derailleurs specifically, (some of them are a little esoteric,) look for a documents stash on your specific model on Disraeli Gears. This has been a huge help for me several times when puzzling out stuff from the '50's and 60's.

Originally Posted by mitchmellow62

Another source that has helped me is velo-pages.com .