Start Measuring Bike Frame Size With These 2 Easy Methods

measuring bike frame size

Measuring bike frame size can be complicated for newbies, whether you want to get a new bicycle or plan to sell one. You need a few easy steps that can help you measuring bike frame size. And these tips will allow you to sell or purchase bikes better. Measuring bike frame size before you buy allows you to get one that is best for your body, allowing you to ride comfortably. 

Even if you intend to sell a bike, measuring bike frame size allows you to know who your potential buyers are. Measuring bike frame size is as same as the length of the seat tube in centimeters. 

Measuring The Seat Tube

A bicycle parked on the side of a building

Size Cable On The Bottom 

The seat tube is elongated to which the bike seat post is attached. On the bottom of the tube, there are approx 7.6 centimeters (3Inches) above the chain sprocket; you will see the bike frame size pasted by a glued-on label. However, not all bicycle frames include a size label.

If the size label is not present on the bike and you have to me maculate it by yourself, then keep these points in mind while measuring bike frame size:

  • Make sure that the frame size is given in either centimeters or inches.
  • Formal bike sizes range from 48 centimeters to 62 centimeters. For the people having short height, the bike size range is the lower one, while for the tall people, it is up to 56 centimeters and more.

Measure From Center 

A row of parked motorcycles sitting in a parking lot

Keep the end of the tape measure at the center point of the rear crank. The move that that tape measures to the top of the tube where the tube ends. This is how you can calculate the length of the seat tube, also the frame size. The common seat tube length in most bikes is approx 53 to 58 centimeters (21-23 inches). 

Convert Into Centimeters

While measuring bike frame size, make sure to convert it into centimeters if the frame size is given in inches, as most of the measurements are given in the centimeters.

How To Choose The Right Size Bike

Measure From Ground To Your Crotch

Now, it is my turn to choose the right size of bike. For this stand on the ground, feet apart ( about 6 – 8 inches), use measuring tape to calculate the distance from the ground to the crotch in centimeters.

Multiplication For A Road Bike

If you want to purchase a road bike, then multiply the measured length by 0.7 to shorter the inseam measure. 

Multiplication For A Mountain Bike 

If you plan to purchase a mountain bike, multiply the inseam measure by 0.66, and you will get the perfect size or length of the bike you want. 


If you planned to buy a bike, then these above are the steps you just follow while measuring bike frame size. And even if you’re planning to sell, these are helpful as well. 

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