Why do my SRAM road disc brake pads rub? Over time, dirt and grime can keep caliper pistons from moving freely and even cause excessive brake noise. To help you achieve the best brake performance, we created this eTap AXS Disc Brake Troubleshooting guide. Related articles How do I fix stuck/sticky pistons in my SRAM DOT brake caliper? How do I bleed my SRAM road brakes? What type of batteries do eTap AXS shift-brake levers require? Can I install my existing SRAM RED eTap HRD brake calipers onto RED eTap AXS or Force eTap AXS HRD shift-brake levers? What is the correct chain gap setting for the SRAM RED eTap AXS 36T Max rear derailleur?