1Aluminum Alloy: The chainring is all aluminum alloy forged, strong and impact resistant, and has uniform force for smooth riding. 2Anodized Process: The surface is anodized to effectively protect the aluminum alloy body and prevent the surface from rust and oxidation. 3Main Features: High precision positive and negative positioning groove for strong bite force. The arc entry angle with positive and negative, wide and narrow tooth shape design to reduce the chain wear, lighten the load of the bike, and the chain will not drop while riding, and the transmission is efficient. 4Mud Discharge Oblique Mouth: The unique sludge discharge oblique mouth prevents the accumulation of silt, and makes the gear drive run smoothly. 5Application: The direct mount narrow wide chainring is suitable for SARM GXP cranks and 811 speed chains, for direct mount cranks and for DUB cranks, used for mounting 148 bike frames. Item Type: 40T Direct Mount Narrow Wide Chainring for GXP Specification: 40T Material: Aluminium Alloy Product Diameter: Approx. 170mm / 6.7in Offset: 3mm / 0.1in Product Weight: Approx. 127g / 4.5oz Process: One piece turning and milling, anodizing Compatibility: Suitable for GXP Crank and 8/9/10/11 Speed Chain Description for GXP Direct Mount Chainring Offset: 1. For SRAM mountain bike crank specifications are all three nail specifications, and the mounting bayonet is universal and has nothing to do with crank specifications. That is, for GXP crank, for BB30 crank, for PF30 crank, for DUB crank, although the crank is different, but the mounting bayonet is the same. 2. Direct Mount Chainring for SRAM are divided into 0mm / 3mm / 6mm / offset. There is no saying that how much millimeters of offset are used for the fixed frame. The larger the chainwheel offset, the closer to the frame. The purpose of the offset is to correct the chain line, which is related to the choice of the crank frame. 3. The frame design has a limit on the number of teeth, and the number of teeth cannot be enlarged infinitely. For example, using 6mm offset discs to install the frame, you can consider using 3mm offset discs, but the chain line should be outside (relatively far away from the frame). 4. In terms of chainring, the cost of 0mm offset is lower and the processing difficulty is low. It is more cost effective to choose the chainring with 0mm offset without considering the chain line. 5. When selecting the offset chainring, when the large flywheel and the small flywheel are the same, in terms of the chain inclination, the use of a low offset direct mount chainring may cause the chain to shift to the large flywheel is too large. This chainring will not drop the chain in this case, but the chainring wear will accelerate, and the greater the inclination of the chain, the greater the chain noise. 1 x NarrowWideChainring