Shimano Cranks


First released in the 1992 model year, XTR is Shimano's eXTRa expensive line of mountain bike parts. The right arm's spider and the majority of the arm itself are fashioned with straight surfaces using a steep curve to join them as the arm passes over the chainrings. Both arms are cold forged, machined for pedals and the bottom bracket, then high polished and Silver (clear) anodized. The cold forging process makes these arms incredibly strong. The XTR cranks employ the Shimano drive principle they call SG-X. The XTR crankset comes with three SG-X aluminum round chainrings. They are grey anodized to give a titanium color appearance. The outer chainring is machined from 3.5mm aluminum plate stock with the backside tapered by lathe so the chain slides smoothly on and off the chainring. The SG-X concept, in fact, has been developed to make chain move more swiftly between each of the chainrings. The middle chainring, (made of aluminum), is stamped from the outside to provide a sloping ramp on the backside for the chain to "ramp up" or down to the inner chainring. The teeth on the middle ring are of different heights with a particular stamping and grinding done on the back of the teeth to pull the chain up from the inner and swiftly let it down to the inner chainring. The middle chainring also has four small, steel, chambered wedges that have been riveted to the back side. These steel wedges have small teeth which assist in seating the chain on the middle chainring as they pull the chain through a set of three teeth that have the second tooth in line considerably shorter than the first and third. These three teeth with the middle cut done provide a "portal" for the chain to flow smoothly through. This is the 1992 variation on the "W-cut" chainrings that Shimano has used for several years. And speaking of recent re- introductions of previous concepts, in the early 1980's Shimano on their Dura-Ace, 600 EX, and DX BMX cranksets introduced the "one key release" system for their cranksets.

The cranks came with a special crank arm bolt with 6mm allen head fitting. This is set in the crank arm cap hole and a special outer crank arm cap screws into the cap hole with a hole that permits the 6mm fitting to protrude through the cap. The cap acts like a shoulder for the bolt as its turned counter-clockwise to press against and push the crank arm off the spindle without the need of a crank puller. Shimano used this "one key release" system for a few years, then abandoned the concept. Oddly in the last six seasons Campagnolo has introduced the same type of release system on some of their cranksets. All this is mentioned because the XTR cranks have what Shimano calls a "Cap-Less" design crank arm. The "Cap-Less" design principle is not the same as the "one key release." With the XTR cranks you get a Chrome plated crank arm bolt that has an 8mm allen head. The head on the crank bolt is made high enough that, with it tightened into the B/B , the head sits flush. A snug fitting Black plastic cap snaps around the bolt, to seal the bolt assembly from outside dirt. An 8" long 8mm allen wrench comes with each set of XTR cranks, so there is more than adequate leverage to cinch the arms on, or break the bolt loose for removal. The benefit of the "Cap-Less" design is that you don't need a 13mm box wrench to remove the crank bolt. For inexperienced bike technicians there is less likelihood of cutting your hand accidentally on a chainring. The weight of the arm cap has been replaced by the plastic ring, and over time the ring may become lost, (replacements haven't been available). You will still need a crank arm puller to remove the crank arm without damaging it. Fortunately, the "Cap-Less" bolts, (the set weighs 31 grams), can be replaced with standard steel, or perhaps Titanium replacements, (better yet Syncros Crank-O-Matics which are a copy of the One-Key-Release). Should you choose to replace them you will need crank arm caps, the Sims or Cooks aluminum set will work fine on these. All the fixing bolts, inner and outer, are made of nickel plated steel. The XTR cranks will work with any 2 degree tapered spindle bottom bracket, but the spindle length must be between 107mm and 113mm, for proper chainline. We found the XTR cranks had a Bike-Pro Q measurement of 169mm. The cranks are made in 165mm, 170mm, 172.5mm, 175mm, or 180mm lengths with the 26-36-46 or 26-36-48 tooth SG-X chainrings. The Shimano XTR crankset comes as right arm, left arm, three chainrings, all required fixing bolts, and a set of chrome and black "Cap-Less" crank arm caps. XTR cranks 175mm long using 26-36-46 chainrings, with all included parts, (but not the 8mm allen wrench), weigh 741 grams. When ordering specify length and chainring sizes.

Length-70-75-80 - Rings 26-36-46=6 or 26-36-48=8 $ Price in Catalog

Shimano M563 Deore Lx Crankset

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