This is by far the most requested, quality rear derailleur today. It uses the Shimano Double Servo-Panta Mechanism. Shimano put everything in this little wonder, and it has many high performance features. It is Shimano Total Integration (STI) compatible, and can be used as a 6, 7 or 8 speed derailleur. Serious users may notice the 1994 m737 XT changer lacks the adjustable return spring, found on last years model, which adjusts the amount of pressure used to shift the chain back to the high gears. It's not clear why this was omitted but possibly it will find its way back on a future model as an "enhancement". There is a "B-Tension" adjuster that permits you to adjust the tension of the mounting spring, and how the entire derailleur supports the chain. The convenience adjuster, (this permits you to adjust, without tools, the cable tension as the cable stretches), is easy to grip with a large Grey plastic jacket around a steel bolt, with detent at each quarter turn. The link pins fastening the left and right links to the derailleur body, and the mounting bracket/mounting bolt assembly are sealed against contamination, to reduce friction.
The XT rear derailleur has what Shimano calls "sealed" pulleys. These pulleys use a series of channels cut into the pulley and seals, but they do not use "precision sealed bearing cartridges". Precision sealed bearing cartridges are commonly called "sealed bearings". The linkages are made of aluminum, with the mounting and pivot bolts made of steel. The pulley bolts are made of steel and the pulley cage has the plate nearest the bike made of steel with protection against spoke damage from an overshift, while the outer plate is made of aluminum. This derailleur comes in a middle cage model called a "GS" or a long cage model which is called the "SGS". The SGS model weighs 235 grams. The SGS will accept cogs up to 32 teeth in size. The "GS" model is rated at a 28 tooth capacity. The XT rear is made of aluminum with plastic pulleys. A 5mm hex wrench will tighten both the cable fixing bolt and the mounting bolt. The steel mounting bolt and the pulley bolts can be replaces with lighter weight Titanium versions found at the end of this article. The pivot bolt isn't replaceable, the pieces at the pivot are permanently pressed (peened) together
M737 XT Long Cage "SGS", M737 XT Middle Cage "GS"
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