Mavic Rear Derailleurs


Mavic makes two rear derailleurs, two that are nominally for use in road bike applications, the 840 and 841, and the third, the 845 for mountain bike applications. The 840 is a short cage, road racing, style derailleur. The 841 rear derailleur, Mavic describes as a "medium cage" rear for use on triple chainring road cranksets in road touring applications. The truth is, the 841 ia an excellent derailleur for mountain use, and is largely identical to the 845 which follows. Like everything made by Mavic, these three rear derailleurs are overbuilt, for peak performance you may never need. They are made to work without difficulty over a long period of time, and then be repaired, as discrete parts of it wear out. Repairs are possible down to the smallest part, because none of the components that make the 840, or 841 are pressed, riveted, or welded together. They are all held together with removable bolts, and a diagrammatic parts lists come with each derailleur. Exactly the same body, left and right pivot links are used in the 840, and the 841, with all the same bolts, fixing assembly, and parts inter-changeability, just the pulley cage, and in the 845 the pulleys are different. Repairs to any failing part is possible, because this derailleur is made to be repaired rather than thrown out when broken. The body and each of the links are made of well forged and finished of 2014 aluminum alloy.

The thickly cast body pieces are given Mavic's CND ("Couche Noir Dure") or Black hard anodized surface treatment, while the left and right link pieces are clear anodized Silver. The high, low gearing, and B-tension adjustments are made using a 2mm hex wrench turning a cap screw. The convenience adjuster and the derailleur mounting bolt are made of machined aluminum. The 840/841, and 845 will work on, and span the shift distance of any 6,7 or 8 speed cogset, and will index with Mavic, and other major brands of indexing systems. The pivot bolt is made of steel, but the exposed surface shows that it's permanently fastened to the inner cage plate, with a broad joining area, dispersing the amount of stress applied to the pivot bolt over a larger area. The pivot bolt is fashioned to bear the load this way, because the pulley cage plates are made of very sturdy Black anodized aluminum. The cage is the most massive we've seen. Both aluminum cage plates are machine forged, die cut, then tapped for the pulley bolts. The inner plate is 5mm thick in all the structural areas, while the outer plate is 3.2mm thick in areas that receive stress. The pulleys are the of a Grey nylon-like plastic, and the bearing assembly in each pulley is different from those of any other maker. Both pulleys have a small needle bearing on the inside, which disperses the load on the pulley across the needle (roller) bearing over a smoothly machined steel axle. The pulleys are surrounded on both sides by a dust cap, which is stamped from plate aluminum, that protects the pulley bearing assembly. Each of the pulleys is held in the cage with two machined steel bolts that are turned with a 4mm hex wrench. Mavic with their derailleurs reaches the outer limits in both quality and price as these are the most expensive rear derailleurs we sell.

Mavic 840 Double $ Price in Catalog
Mavic 841 Triple $ Price in Catalog

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