Shifters
Parts
Shimano Tiagra 4700 Shifters
Tiagra 4700 shifters are not compatible with shimano's 10 speed derailleurs because it shares the pull ratio of the 11 speed drivetrain.
Bookmarks
Component Weights - Damon Rinard
Vintage parts weights.
Brainy Biker Will a 9-speed Derailleur Work On a 10-speed Cassette?
Lots of information on calculating cog pitch, pull ratio, cable pull for derailleurs and shifters.
Articles
Alternative Shifters
Most road bikes today come with integrated brake and shifting levers, or brifters. They are more comfortable and usable than traditional styles. Let's look at some available options.
Shifting mechanisms
Shifters work by increasing or decreasing the tension on the shift cables to move the derailleur into place.
Indexed
Indexed shifters click into place and move the derailleur one gear. They allow for precise shifting, but need to be tuned and parts are made for specific speeds and derailleurs. Brifters are all index shifters.