What is the purpose of a chain retention tab?

If you have had the opportunity to ride on extreme roads such as the Roubaix cobblestones or in Cyclocross, you are almost certainly familiar with the anxiety of dropping the chain.

The answer to this fear of dropping the chain is the chain retention tab! Keeping the chain within the range of the front derailleur, and thus preventing any chain drop, it is generally designed to be fitted on a "braze-on" system but can also be found on clamp-type derailleurs.

Beyond extreme disciplines, it also helps to make your drivetrain more reliable and avoid unpleasant surprises that could lead to a fall, particularly when shifting from the big to the small chainring when your front derailleur adjustment is not perfect.