A full-face mountain bike helmet is necessary when riding on aggressive terrain, such as downhill or freeride trails. It provides additional protection for the face and chin, which can be vulnerable to impact during a crash. A full-face helmet also offers better coverage and superior ventilation compared to a traditional open-faced helmet. Ultimately, the type of helmet you choose should depend on the type of riding you plan to do.

To seal tubeless mountain bike tires, first remove the tire and clean the rim and tire bead thoroughly. Apply a tubeless valve to the rim and insert it. Add sealant to the tire, then inflate the tire with a high volume/low pressure pump. Shake the tire to distribute the sealant evenly inside. Then, re-install the tire over the rim, ensuring that the tire bead is seated properly. Inflate the tire to the recommended pressure and check for sealant leaks. Finally, ride the bike to distribute any remaining sealant to any small gaps in the tire.

To change the back tire on a mountain bike, first, shift into the smallest gear on the rear derailleur, and then flip the bike over so it rests on the handlebars and saddle. Next, remove the quick-release skewer, and gently slide the wheel out of the frame. Detach the tire from the rim by releasing the tire lever, and remove the inner tube from the tire. Replace the tire, add the new inner tube, affix the tire back to the rim, slide the wheel back into the frame, and tighten the quick-release skewer. Finally, test the tire pressure and ensure the wheel is securely in place before riding.