If you are going to purchase a bike, knowing how to measure bike frame is mandatory. This is the best way to avoid getting a too big / small bike. Although sold in different variants, the measuring process is the same.
The numbers are obtained by measuring the seat tube distance. This is the vertical portion of the triangle. It extends from the start of the seat post to the point where it joins the upper tube in the center of the crank. The seat post refers to the stem that keeps the seat in position.
The upper tube is the bar across a bike’s top. The crank is the circular component in the center. To learn how to measure bike frame, get a measuring tape. The figure you get is the distance in inches. If you are looking for a new bike, use that figure as a guide.
The top tube is important. This is the distance between the handlebars and bike post. This is essential for ease of reaching brakes and gears. If well fitted, neck and back strain will be avoided.
Differences in Measurements
Bike manufacturers may use different sizing methods. But most of them round the numbers to the closest inch. The majority of products are sold in increments of two inches. Most mountain bikes are sold in 15 inch, 17 inch and 19 inch frames. Other frames are labeled small, medium, large or extra large.
Size Guide for Full Suspension Mountain Bikes (Height in Inches)
Riders who are 5’4” will do well with 16″ frames. 17″ are for those 5’6” 18″ frames are for 5’8” and over. If you stand 5’9”, get a 19″ frame. Those who stand 5.10 are better off with a 20″ frame.
Mountain bikes for off-road use (no full suspension) have many choices too. 18″ frames are for 5’8” riders. If you are 5’9”, the proper frame is 19″. The suggested frame for those who are 5’10” is 20″.
These figures and those on other charts online are guides. The only way to find the right size is by straddling. The clearance from crotch to top tube must be two inches minimum. The handlebars must be within easy reach.
The key to learning how to measure bike frame is understanding the parts of the bike. Unless you know what they are, you’ll have a hard time figuring out instructions. If you know the components, taking measurements will be easy.