How to Tighten the Stem on Your Mountain Bike for a Safer and More Comfortable Ride
To tighten the stem on a mountain bike, first loosen the bolts located at the front of the stem with an Allen wrench. Next, adjust the stem to the desired angle or height and tighten the bolts back up, making sure they are even on both sides. Finally, test the stem by trying to move it side to side or up and down. If it moves, tighten the bolts further until it is securely in place.