My drivetrain required total capacity is 14.

(folding bicycle Dahon Eco C6, 14-28 rear, 1x front)

The rear derailleur (Shimano TZ50, which I purchased), has total capacity = 34 and a long cage. Are there are any disadvantages, in such overkill, when total capacity of the derailleur (34) is much higher than required (14).


There's a huge disadvantage for a Dahon and any other small-wheeled derailer bike, which is that the cage is gong to be unfortunately close to the ground no matter what you do, and having a longer cage than necessary makes the problem worse.

Shorter cages also manage chain slap better and are lighter.

  • Related - longer derailleurs on small-wheeled bikes seem to get even dirtier faster than any other wheel size.
    – Criggie
    Nov 17 '19 at 10:59
  • Why the original dahon eco c6, (eu.dahon.com/bikes/eco-c6), use the long cage cave (Total Capacity: 34 instead of 14)?
    – Michael D
    Nov 17 '19 at 11:46
  • 1
    @MichaelD Likely because very basic rear derailleurs like that typically only come in long cage. Nov 17 '19 at 18:05

As you no doubt know, the cage length is a significant factor in determining the link capacity of the derailer. But having a longer than necessary cage has several disadvantages.

One disadvantage is that a longer cage tends to result in less precise/less "crisp" shifting. Another disadvantage is that the longer cage is easier to damage.


Chain tension and control over bumps is reduced because the mere is greater leverage in the cage vi the lower pulley.

On a folding bike with small wheels you may find you have ground clearance problems.

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