Shimano Altus With a variety of high-quality technical features - including stable 9-speed drives, V-brake and disc brake systems or easy-to-use gear levers with Rapidfire Pus technology, the Altus offers reliable performance for recreational driving pleasure. - Purpose: Trekking chainrings - Number of chainrings: 3 chainrings - Gear ratio: 28/38/48 teeth Crank - Type: 4-arm - Axle mount: square - Pitch circle: 104/64 mm - Pitch circle type: standard - Compatibility rear derailleur: 8-speed chain guard - Chain guard ring