Other Chain Guides

Derailers are the name given to the front part of a derailleur which crosses the chain over from one chain ring to another. Derailuers all operate in the same way: A shift fork is rotated to the right and/or left by a parallelogram and, in doing so, curls up the chain on the side from the chain ring being used to a larger or smaller one. A derailer can be used to select the bike’s so-called “rough gear transmission ratio”. Since specific derailers exist for MTB and racing bikes which would not be compatible with a large 3rd chain ring on a touring bike, this category is offered as an added extra.