Question: how much air pressure should be in a bike tire?
Answer: Pump it up. Proper tire pressure lets your bike roll quickly, ride smoothly, and avoid flats. Narrow tires need more air pressure than wide ones: Road tires typically require 80 to 130 psi (pounds per square inch); mountain tires, 25 to 35 psi; and hybrid tires, 40 to 70 psi.