Things You'll Need
Instructions
Turn your bicycle upside down and place it flat on the ground.
Loosen the bicycle's two rear bolts, which are adjacent to the rear sprocket, with a crescent wrench. The bolts only need to be loose enough for the wheel to freely move around.
Maneuver your bicycle wheel horizontally so it's aligned with the middle of the frame. If the wheel is too far to the left or right, the sprockets won't line up properly.
Slide the bicycle wheel backwards slightly, away from the front of the bike. Test the chain tension by gripping it with your hand and moving it up and down. There should be a small amount of give in the chain's tension. If the chain is too loose, it'll fall off the sprocket. If the chain is too tight, it'll be noisy and cause extra friction, which will slow down the bicycle. When you spin the pedals, there should be little to no noise.
Tighten the bicycle's two rear bolts and flip the bicycle back up into an upright position.