An armored car among derailleurs, this Shimano Saint rear derailleur is compatible with the Saint 135x10 rear hub (FH-M801), which it attaches to via the axle. It’s a top normal design, which works most easily with RapidFire Plus shifters.

Since it is a Saint, we ought to detail the protection this derailleur offers. First, there’s an adjustable bump stop, which reduces noise and minimizes damage to both the frame and rear derailleur. There is a cable tension saver, which allows the rear derailleur to be hit and yet hot get tugged too hard by the cable when the derailleur is out of position. The whole design is kind of a practical skid plate, particularly the lower surface which has a habit of finding hard objects to grind against when one is enjoying landing, rock gardens, curbs, posts, etc.

The Shimano Saint RD-M801 rear derailleur comes in three sizes, the SS, GS, and SGS -- think of them as short, medium, and long cages, respectively. The SS has a capacity of 29 teeth, the GS 33, and the SGS 45. All are designed to work with nine cogs. The largest cog it can work with is a 34, the smallest, an 11. The tension pulley runs on a sealed bearing, whereas the guide pulley runs on a bushing. The bracket and plate bodies are forged from aluminum and painted (scratches make the derailleur look better). The remaining parts are aluminum, save the pivot bolt and inner link, which are steel. 359g (SS)/ 369g (GS)/ 395g (SGS). MSRP $129.99.