The introduction of the Shimano GRX group is a big deal. Not just because it's the industry's first groupset designed specifically for gravel riding and racing, but also because it's the first time Shimano offers a dedicated 1x crankset outside of their mountain bike lineup. For riders seeking the simplicity, reliability, and improved chain retention of a single-ring drivetrain on their gravel or all-road bike, look no further than the GRX FC-RX600 1x Crankset. As you might've guessed, it's designed to work with Shimano's GRX 11-speed gravel group. That being said, it would work just as well if you wanted to throw it on your existing bike that's already equipped with Shimano 11-speed road components. Shimano spent over two years getting feedback from gravel enthusiasts when developing the groupset that will ultimately tackle dirt and gravel roads and singletrack on drop-bar machines. It learned that rider's wanted the option of 1 or 2x setups, wide gear ranges with low enough gears to tackle tough climbs, and of course, reliability. The GRX FC-RX600 gives you all this, and works flawlessly with the rest of the GRX 11-speed lineup. It also comes in at a much more palatable price than the premium GRX RX810 cranks, albeit with a modest 100g weight penalty. The crank is constructed of durable, lightweight, and stiff aluminum alloy, and is equipped with a 40t chainring that provides the low gearing needed for tackling tough climbs, without sacrificing too much top end speed when you've got a long descent ahead with a tailwind at your back. The real strong point of a 1x drivetrain, however, is the simplicity and improved chain retention that we mentioned above. This is accomplished in part by specially engineered tooth profiles that ensures positive shifting without the risk of dropping your chain, even in muddy and dusty conditions.Bolts: 4. Bolt Circle Diameter: 110mm. Chainring Sizes: 40t. Arm Length: 165, 170, 172.5, 175mm. Arm Material: aluminum.Date First Available: November 17, 2009. Best Sellers Rank: #226,973 in Sports & Outdoors. Customer Reviews: 4.5 out of 5 stars 8 ratings 4.5 out of 5 stars. : B07VQZFWPT. Sport Type: ?Cycling. Size: ?170mm, 40T. Part Number: ?EFCRX600111CXB0. Manufacturer: ?Shimano. Number of Items: ?1. Material: ?Alloy. Color: ?Black. Brand Name: ?SHIMANO. Item Weight: ?3.4 Pounds. Item Dimensions LxWxH: ?12 x 9 x 8 inches. Package Weight: ?3.4 Pounds. Item Package Dimensions L x W x H: ?12 x 9 x 8 inches.