Shimano's M737 is the new HyperDrive-C Deore XT crankset. The HyperDrive-C cranks use much shorter spider arms and smaller chainrings which reduce the on-bike weight of the cranks. Previous versions the XT cranks were cold forged, this is no longer a feature Shimano promotes so the M737 must be forged using a more common molten aluminum process. After forging, the spider has some milling work performed to take off burrs and give the arm a clean line for the chainrings. They are then drilled for the dust caps, spindles (both B/B and pedal), and the fixing bolts. The B/B spindles are broached to make the 2¡ tapered square for the B/B spindle and tapped with 22mm x 1mm threads for the dust cap, and the 9/16 x 20 threads for the pedals. The arms are given a fine, even, textured surface, then clear anodized leaving a Silver color, left as un-painted aluminum they are easily able to be inspected for defects or cracks. Each of the arms has the name "Shimano Deore XT" screened Black lettering near the B/B spindle, (you may remember when these were still cold forged cranks that the name was engraved in the face of each arm, this is likely a casualty of the Dollar/Yen exchange rate, creating a high yen value or "Endaka"). The XT cranks come with three SuperGlide SG-X type, round chain- rings, using the Shimano standard 58mm inner and 94mm outer bolt pattern. The outer aluminum chainring shows some splendid workmanship. Made of 4mm thick aluminum plate, the piece is very cleanly die- cut to shape, then turned on a lathe to reduce the thickness to the 2.12mm The chainring is stamped to make the tooth points and give them the necessary shape for the SG-X shift gate pattern. Certain parts of the inner side of outer chainring are milled away to make the beds for the four SG-X steel pins used to lift the chain to the top of teeth. Two SG-X portals exist on the outer chainring which are anodized Black before the steel pins and the aluminum anti-jam pin are riveted to in place. The middle chainring is made of 2.6mm thick aluminum plate, that is die-cut then turned on a lathe to reduce the thickness to 2.0mm in the area of the teeth. The piece is stamped to give it necessary corrugation for the SG-X feature, make the points of the teeth and the SG-X shape to the teeth. The middle chainring is anodized in a Silver color, then the 4 steel shift gates are riveted to the back of the piece. The inner chainring is die-cut from steel plate, turned on a lathe to taper the tooth points, then Chrome plated. The inner chainring is a high wear point traveling several more revolutions than the middle and outer, the use of a steel inner is wise. The crankset comes with 5mm hex head fixing bolts to fasten all three chainrings to the arms. The fixing bolts and nuts are made of steel. The bolt set to hold the inner chainring is also made of steel and has 5mm hex fittings for removal. Included is a set of Shimano "cap-less design" crank bolts. These bolts are made of chromed steel with an 8mm hex fitting for removal or installation of the bolt, (to remove the arms without damage, will still require a crank arm pulling tool). Around the out- side of these 13 grams bolts a Black plastic dust seal snaps. XT cranks will work with any 2 degree tapered spindle bottom bracket, Shimano recommends using a 107 or 113mm spindle length. We stock the cranks in 170mm, 175mm, or 180mm lengths with either 22-32-42 or 22-32-44 tooth SuperGlide chainrings. We can also special order if needed the XT cranks in a 165mm length. The Shimano XT crankset comes as right arm, left arm, three chainrings, all the required fixing bolts, and a set of chrome capless crank bolts. XT cranks, 175mm long, using 22-32-44 chainrings, with all included parts, weigh 696.5 grams. When ordering specify length and chainring sizes.
Length-65-70-75-80 - Rings 22-32-42=2 or 22-32-44=4 $ Price in Catalog
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
This is Shimano's entry-level performance/competition crankset, and brings with it all the functionality of the more expensive XT cranks. The aluminum alloy arms are clearly melt forged. Like other cranks the dust cap, fixing bolts, the B/B spindle and the pedal spindle. The B/B spindle hole is broached to making it four sided, with 2 degree tapers for any standard B/B. The dust cap hole is tapped with 22 x 1mm threads for a standard cap or crank removal tool, and the pedal spindle hole is tapped with the needed 9/16" x 20 threads. There is no serious post- forging polish work done on these arms, but they have a fairly smooth finish out of the mold, which made more smooth by painting them with a high gloss Black paint. The paint makes pre- purchase inspection for defects difficult and also makes difficult to see small fatigue of stress cracks developed later in use. The Deore LX crankset comes with three SuperGlide round chainrings, the middle and outer of which are the SG-X type using a 94mm bolt center diameter for mounting. The inner chainring uses a 54mm BCD and appears to be the same type used on the XT cranks. The mid and outer chainrings are poorer in quality when compared those used on the XT. The outer is die-cut from 2.9mm thick aluminum plate that has the has the original foundry brushed surface. The outer, once stamped is turned on a lathe to reduce the thickness in the area of the points to 2.0mm thickness. The teeth are stamped after the lathe to make the needed tapers and points on the teeth as well as SG-X depressions in the teeth and chainring for the shift gates. Four steel pins placed at the 3 and 9 o'clock positions are used to help lift the chain into place on the outer chainring, helped by notched and shorter teeth. The middle is also die-cut from aluminum plate, in this case 2.6mm thick that is turned on a lathe to reduce the thickness to 2.0mm in the teeth area. The piece is then stamped to give the teeth points and depressions as needed for the SG-X functionality. Four steel shift gates, one at each compass point are riveted to the chainring's back. The outer and middle are generally clear anodized leaving them a Silver aluminum color, there have been odd instances when we have received LX cranks with a Black outer chainring, but it cannot be depended on. The chainrings are middle and outer fastened bolts and nuts are made of Black painted steel, using a 5mm hex fitting for removal. The inner bolt set is made of nickel plated steel with 5mm hex fittings for removal. LX cranks come with two chrome plated, "capless design" crank bolts. These bolts have an 8mm hex fitting so a long handled 8mm hex wrench can be used for removal and tightening. You will however still need a crank arm pulling tool to remove and arm from the spindle without damaging it. Black plastic dust seals snap around the bolts. LX cranks will work with any 2 degree, tapered spindle bottom bracket. The cranks are made in 170mm, or 175mm lengths using just the 22-32-42 tooth SuperGlide chainrings. The Shimano LX crankset comes as right arm, left arm, three chainrings, all the required fixing bolts, and a set of chrome crank bolts. 175mm Deore LX cranks using 22-32-42 chainrings, with all included parts, weigh 697.5 grams. When ordering specify length and chainring sizes.
Length-70-75 $ Price in Catalog