How to Measure Bike Tire Size
Everyone needs to replace their bicycle tires; age and damage will eventually force the issue. It is a simple and easy matter but sometimes, you may not know the proper size of the tire you need to replace. Most tires are marked but in case yours isn’t, follow these simple steps to determine the correct size.
- Insure the bicycle tires are inflated to the proper size. Use a bicycle tire air pressure gauge to check. You want to be sure the tires are inflated correctly because over inflated or under inflated tires will give inaccurate readings.
- Prop the bike against a wall or other supportive surface so that is stands up straight on both wheels.
- Using as tape measure, carefully measure the diameter of the bike tire. Start at the base of the tire, in the center. Measure upwards to the top of the tire in a vertical line. Measure from where the rubber touches the ground to the tread on the top of the tire. The resulting number should be the tire size. If the measurement is a fraction, round up. Measuring in millimeters gives the most exact measurement, but you may not be able to match it exactly to the standard size. Round to the closest standard size.
- When purchasing your tubes or tires, be aware that they are sold with two measurements. The bike tires’ diameter and the width. Common bike wheel diameters are 12½, 16, 18, 20, 24, 26 and 700 mm. The width is determined by the width of the tire and can be changed if you wish.