Trek Angle-Adjust Headset Cup

Adjust head tube angle one degree slacker or steeper on compatible Trek mountain bikes with these angle-adjust cups. Start with the appropriately sized upper cup for your frame size, then add the universal lower cup. For Fuel EX Gen6 and Fuel EXe Alloy, short upper for XS-L, tall upper for XL-XXL. For Slash Gen6, short upper for S-ML, tall upper for L & XL.