To use this gyro, the outer diameter of the head tube must be 54 mm or less. This MTB-specific gyro is machined in Canada from domestic 6061 T6 aluminum and is designed for street, flowing dirt lines, skate parks, or slopestyle courses. It is recommended to use a pressed headset and mounting grease for installation. Some frames may require gyro tabs in conjunction with the bottom. It features a machined Delrin bushing with low friction and high wear resistance. Two sizes are available, depending on the outer diameter of the head tube. The fork steerer requires an additional approximately 2 cm of space below the stem due to the installation height. Gyro tabs are not included. Maximum outer diameter of the head tube is 54 mm. Requirement: 44 mm zero stack headset cup. Compatibility for size Small includes: Black Market, Banshee, Chromag, Commencal, Corsair, Dartmoor, Giant, GT, La Bomba, Kona, Morpheus, Mongoose, Marin, Rose, Santa Cruz, Specialized, Transition, Pivot, Polygon. If you do not see your frame listed or would like to know more about installation, please visit Title MTB. Note: Brakes are best installed by a professional as they are safety-critical components.