Medium Cage Rear Derailleur

Medium Cage Rear Derailleur

Ultegra RD-6870-GS

The Shimano RD-6870-GS is the medium cage rear derailleur for the 6870 series.

It supports a max front difference of 16T, a low sprocket minimum of 28T and a low sprocket maximum of 32T. The top sprocket maximum is 12T and the minimum is 11T. It has a total capacity of 37T and weighs only 11g more than the short cage derailleur - 268g.

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It also features Shimano's Crash Protection Mode - this prevents shifting after a crash to make sure the rear derailleur is damaged any further. To restore shifting functionality have a look at the FAQ: I had a small crash and my rear derailleur stopped working.

When paired with the BT-DN110 battery, synchronized shift is enabled for this derailleur. Read more on synchronized shift in the complete guide to synchro shifting.


  • Model code: RD-6870-GS
  • Series: Ultegra (6870)
  • Weight: 268g
  • Speeds: 11
  • SD50 ports: 1
  • Max front difference: 16T
  • Total capacity: 37T
  • Low sprocket max: 32T
  • Low sprocket min: 28T
  • Top sprocket min: 11T
  • Top sprocket max: 12T
  • RD type: Non-shadow RD
  • Clutch: No

Related components

View the Short Cage Rear Derailleur (RD-6870-SS)


Short Cage Rear Derailleur

View the Dual Control Lever (ST-6870)


Dual Control Lever

View the Below-the-stem Junction A (SM-EW90-A, SM-EW90-B)

SM-EW90-A, SM-EW90-B

Below-the-stem Junction A

View the Internal Battery (BT-DN110)


Internal Battery

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