alpha Racing Custom Front Sprocket T19 520 BMW S1000RR/HP4 (2010-, 2015-) manufactured from enhanced case-hardened, core-refined nickel-chrome-molybdenum alloy steel for the ultimate combination of strength and hardness, T19, pitch 520, for BMW S1000RR and BMW HP4. These sprockets are CNC-machined (not stamped) and feature a computer-aided “Ultra light” design to reduce unsprung weight and increase power transfer. These front sprockets also feature a specially CAD designed tooth profile that allows the 520 chain to roll easily on and off the sprocket for longer wear, less noise and more power. Weight: 0.20 kg. Note: BMW S1000RR Stock Gearing: 17-45. These are custom order and will take 3-4 weeks to deliver - special orders are non-refundable.