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.
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 our FAQ I had a small crash and my rear derailleur stopped working. What happened?

Details & specifications
Shimano model code | RD-6870-GS |
Shimano model name | Medium cage rear derailleur |
Weight | 268 g |
Series | 6870 |
Downloads |
Di2 Rear derailleur manual Ultegra 6870 manual |
View on | Amazon (new tab) | eBay (new tab) Chain Reaction Cycles (new tab) |