Following are some simple guidelines for figuring out the proper frame size to accommodate your unique body geometry. There are lots of other factors, like bottom bracket (BB) width, seat height and handle bar width that go into proper fitting, but if you can match the proper frame size to your body, you should be able to achieve a comfortable and enjoyable ride.
Some bikes may use a basic designation such as S, M, L or XL. Others may provide a numeric frame “size”, listed in inches (i.e., 18″) or centimeters (i.e., 54 cm). Each person’s physical dimensions and attributes (i.e. arm length, torso length, femur length, flexibility, etc.) are slightly different and can lead to different frame size needs even for people of the same height.
If you are in between two sizes it is often best to go with the smaller size. It is easier to make a smaller frame fit a little larger than it is to attempt the reverse. Fitting is an important process which directly affects the ride quality and comfort of a bike.
|Height||Mountain/Hybrid Size||Road Size|
|< 5' 2"||13/14||43/47|
If you are comfortable with or would prefer a more precise approach to determine your correct frame size, you will need your actual inseam length. This is a measurement for bike sizing purposes and will likely be different than your pants length.
For this measurement, stand in stocking feet with your back against a wall. With your feet about eight inches apart (pedal width), place a carpenter’s square (a notebook also works) tight against your crotch. It should be tight enough to simulate sitting on a bike. The other plane of the square should be against the wall. With a yardstick, measure from the floor to the top of carpenter’s square or notebook. Repeat several times and average the results. If you measured in inches, convert to centimeters by multiplying by 2.54.
To find your frame size, multiply your average inseam in centimeters by .67. For example if your inseam is 33 inches, multiply 33″ x 2.54= 84cm x .67= 56.28 cm. The frame size for a 33 inch inseam would be 56 centimeters.
While height is a good starting point it is no substitute having your local dealer view your child on a bike to determine what is the appropriate fit. This is especially important as kids’ skill levels can vary greatly. A child who is very skilled at riding a bike may be comfortable on a larger bike than a child of the same height who has just learned to ride without training wheels.
|Height||Kid’s Bike Size|
|35 – 40″||12″|
|39 – 46″||16″|
|45 – 52″||20″|
|51 – 63″||24″|
City Bike Tampa offers fitting services in our shop and can provide for everything from basic sizing recommendations and adjustments to things like your seat post, saddle, stem and handlebars to a full performance fit to get you the most out of your training and competitive endeavors.
Please call (813-225-1777) or email us for details. Ride On!