Length Does Matter:

Derailleur Cage Counts:

Too much chain length and you'll have shifting issues and suffer from dropped chains, but too little could rip your bike's derailleur right off. Have we scared you into checking the chain length on your bike?

Chain length is one of those important setup points that often gets overlooked both when building up a bike from scratch, or when replacing a worn chain. In fact, it is so common that there is a good chance that many of the bikes on your local shop's showroom floor are sporting too long of a chain, an oversight from the factory that can often lead to dropped chains or inconsistent shifting. While an over-length chain can cause some annoying issues, one that is too short can be downright catastrophic. The best case scenario is that your bike will refuse to shift to the larger sized cogs or chain rings due to too much chain tension. Worst case: you could not only rip off your bike's derailleur hanger or destroy the chain and derailleur itself but even bend over the chainring due to the massive forces involved. It's fair to say that a bit of carelessness when it comes to chain length can quickly make for an expensive repair bill.Your bike's rear derailleur also plays an important role in managing chain length. Its hanging cage and pulley wheels take up the chain's extra slack when in small cog and chain ring gearing combos, but the spring-loaded cage can also rotate forward to compensate for added chain tension when you are in a larger sized cog or chain ring. Derailleurs are available with short, medium, and long cage lengths depending on what your bike requires. The general rule of thumb is that the larger the gearing range, the longer the derailleur cage needs to be. This is because of the massive difference in chain slack when in certain gearing combos on bikes with three rings and wide range cassettes, while bikes with only a single chain ring can often get away with a short cage derailleur. Using a short cage derailleur on a bike with a very wide gearing range () will require a chain that is overly long to compensate for the lack of capacity in the derailleur's short cage, while the opposite is true of a long cage derailleur on a bike that doesn't necessitate it - there will be no happy medium setup. In short, the wrong length derailleur cage will make determining proper chain length nearly impossible.