SHIMANO DERAILLEURS - REAR
Shimano XT Shadow Plus RD-M786 Rear Derailleur
- Item: SHI0604 Actual Weight:"Actual Weight" means we weighed this item ourselves. 262 g
When Shimano introduced its Shadow line of derailleurs, it was a big departure from the norm, but it offered better clearance and enhanced shifts due to a re-positioned B-knuckle. This, however, required an additional link. While sufficient, there's a growing trend of simplifying mountain bikes -- both in favor of reduced weight and reliability. Thus the introduction of the new direct mount standard for Rear Derailleurs found here on he XT Shadow Plus RD-M786.
If you're still using traditional hanger, the RD-M786 comes with a link installed so it's backwards-compatible. The direct mount, however, eliminates the need for the link, effectively reducing flex, wear, and weight -- all good things to mountain bikers. On compatible frames, the system also allows easier wheel changes with thru axles. Another big change is the stabilizer switch trickled down from XTR and Saint derailleurs.
When engaged, this switch helps to eliminate chain slap and dropped chains by increasing spring tension. This is a valuable option for suspension systems that require chainstays and pivots located close to the rear deraileur. the RD-M786 retains all the last models improvements, including the direct cable path. Your shift housing can enter the stop on the derailleur without the traditional loop of excess housing that often was the victim of contamination and a source of poor performance.
Shimano uses tried-and-true aluminum components in the XT derailleurs. All of the knuckles, linkage plates, and cage sides are made from it. So while it may lack the wow factor of the carbon fiber-laden XTR Shadow, it's more affordable, and if you've been running XT derailleurs as long as we have, you'll know that you'll get plenty of mileage out of it.
The RD-M786 is available with two cage lengths -- Long (SGS) and Mid (GS). The length of the cage determines the overall chainwrap capacity, or how big of a tooth difference it can accommodate between the biggest gear and the smallest gear. Total difference can be found with this equation: big chainring minus small chainring plus largest cog minus smallest cog.
For example, the long cage (SGS) option will work with a 24/32/42 chainring configuration (18t difference) plus an 11/36 cassette out back (25t difference). This meets the maximum chainwrap capacity of the long cage derailleur (43t). The mid length Shimano XT Shadow Rear Derailleur RD-M786 cage (GS) has a chainwrap capacity of 35t and could be used for a single or double ring/bashguard set-up as the 11/36 (25t difference) plus the 24/32 chainring (8t difference) does not exceed its range.