Speeds, shifters, derailleurs

Bicycle front derailleurs explained: how they work, mounting standards, clamp and direct-mount types, cable pull, swing designs, and double vs triple compatibility.

Bicycle rear derailleurs explained: how they work, mounting types (hook, standard, direct mount), cage length and capacity, max sprocket size, and compatibility basics.

Bicycle gear ratios (“speeds”) explained. What are “gear inches”? What are the needed gear ratios for climbing, downhill. What to pay attention to.