UB Machine
http://www.ubmachine.com
Chassis components
Ultra Cool Brake Fans
http://ultracoolbrakefans.com/main/
Hub mounted brake fans
Ultra-Lite Brakes
https://ulbrakes.com/
Titanium and coated racing brakes and rotors
Ultra-Shield Race Products
http://www.ultrashieldrace.com
Tear-offs and helmet accessories
UMI Performance
http://www.umiperformance.com/
Suspension components and sway bars
Unisteer Performance Products
http://www.unisteer.com/
Ring and pinions and steering components
US Gear
http://www.usgear.com/
Performance racing and street ring and pinion gear sets