Keep in mind that the frame size may be listed in either inches or centimeters. Common bike sizes range from 48 cm–62 cm. Bikes at the lower end of that size range are meant for shorter individuals, while taller people will need bikes sized 56 cm and up.

If it helps you measure, you can remove the seat from the top of the tube and set it aside so the seat doesn’t get in the way. Most regular-sized bikes have a seat tube length that’s around 21–23 inches (53–58 cm).

Say that the length of the seat tube is 22 inches long. Multiply this by 2. 54, which 55. 88 cm. If you’re working with a mountain bike frame, leave the measurement in inches.

If you find that it’s awkward to measure this distance on your body without falling over, ask a close friend or partner if they’d be willing to help.

Say that you measure the length of your inseam at 65 centimeters. Multiply this by 0. 7 and you’ll come up with 45. 5. Rounding up, you’ll have an answer of 46.

Mountain bikes are your best bet if you’ll be doing the majority of your cycling off-road or over rocky terrain. For example, say that your inseam measured 76 centimeters. Multiply this by 0. 66 and you’ll get roughly 50.

If the bike doesn’t feel right or if you struggle to reach the pedals, try a different size until you find a bike that suits you. If you purchase a used bike that doesn’t happen to display its size, you can pull out your tape measure and measure the seat tube to find the size.

Make sure not to include the base of the handlebar post in this measurement! The head tube is by far the shortest of the main bike tubes. Because of this, measurements for the head tube are typically given in millimeters, while most other measurements are typically given in centimeters.

It wouldn’t hurt to place a tiny piece of masking tape at the point you measured, so you won’t forget where to measure the effective top tube length. The piece of tape should be straight across from the intersection of the head and top tubes at the exact same height. It’s important that you use the level to make sure these 2 points are as high as one another. If the top tube is flat, skip this step and move directly to measuring the length of the tube. Slanted top tubes are lower where they intersect the seat tube and higher where they intersect the head tube. This is fairly common on bike frames, especially for road bikes.

The top tube is the tube that’s situated between your legs when you ride a bike.