How to Easily Fix a Flat Tire on Your Mountain Bike
To fix a flat tire on a mountain bike, first remove the wheel from the bike. Remove the tire and tube from the rim, locate the hole or puncture in the tube, and patch it or replace it with a new one. Inflate the new or patched tube slightly and insert it back into the tire, ensuring that the valve stem is in the correct position. Align the tire and rim and reattach the wheel to the bike. Pump up the tire to the recommended pressure and check that there are no leaks.