Extremum:~ The Extremum RacePrepª bottom bracket is the first external BB designed for BMX racing. Unlike mountain biking where bikes are exposed mud and water, BMX racers typically ride in relatively clean environments.
• Features non-contact, titanium-coated SUS bearings, modified low-friction seals and lightweight lube
• May require more frequent maintenance, depending on your riding habits
• The titanium coating results in a low friction coefficient, increased corrosion resistance and smoother rolling bearings