Books on How to Measure a Bike Online
Knowing how to measure a bike, particularly a bike frame, is important, especially if you’re trying to buy a bike, sell a bike, or figure out how tall a person should be to ride a bike with a specific measurement. It’s important to measure specific aspects of the bike frame to determine the size of the bike.
If you measure a bike incorrectly, you will end up with an improper fit. This leads to cycling discomfort, poor posture, decreased efficiency and enjoyment while riding, and possibly even pain for the rider, so read ahead to learn how to measure a bike properly.
Common Bicycle Measurements
- Center to Top (C-T)
This measurement refers to the length of the seat tube from base to top. The top is where the seat post goes into the seat tube, and the base is the section at the bottom holding the bottom bracket. This measurement is important because if it’s too short, the rider’s knees will come up too high while pedaling, and it’s too long, the rider will not be able to properly reach the pedals. If you’re just learning how to fit a bike, it’s important to know that this measurement usually applies to road, mountain, comfort, and hybrid bicycles.
- Center to Center (C-C)
This measurement is very similar to the center to top measurement, but the top of the seat tube is defined differently. Instead of the top being where the seat connects, the top of the seat tube is defined by the intersection of the center of the top tube and the center of the seat tube. This measurement is more common among European road bike manufacturers.
- Top Tube (TT)
If you already know how to measure a bike, and this measurement seems unfamiliar, you should know this measurement primarily applies to BMX bikes. This measurement is the length of the top tube or the main connecting tube between the seat tube and the head tube (the tube holding the front wheel). It is measured from the centers of each intersecting tubes.
- Wheel diameter (D)
Most people who do not know how to measure a bike usually know the diameter of the wheel is an important measurement. This measurement is particularly important for cruisers and kids’ bicycles. Typically, the larger the size of the tire, the larger the frame of the bicycle is. The frames are designed relative to the size of the tire. This measurement is simply calculated by measuring the length around the wheel. If you don’t know how to measure a bike, it’s helpful to know most bicycles use one of three sizes: 26”, 27”, and 29”. Knowing the diameter of your bike’s tires is important to replace tubes, tires, spokes, etc. You can usually find the tire size of your bike by looking at the existing tire.
- Crank Size (L)
Most bikes have standard crank sizes, but it’s helpful to know the length of your cranks. They are usually measured in millimeters (mm) from the center of the holes at each end of the crank.
- Overall Bike
If you don’t know how to measure a bike, overall bike size will give you a reference point of where you want to begin for an initial purchase, gift, or replacement of your current bicycle. Overall measurements are usually small, medium, large, or extra-large. Sometimes these measurements apply to bicycles with an upright, casual riding position, which is easily adjustable to accommodate a range of riders. Bicycles with overall measurements are for more casual riders, and these bicycles are much less custom, and more one-size-fits-all.
Did you know...?
Did you know that having a slightly shorter crank is much safer than having an excessively long one?
Although a longer crank does provide more leverage, making for easier pedaling, simply switching to a lower gear will achieve the same effect.
Riding a bicycle with an overly long crank will cause knee pain over time due to excessive flexion. If you're confused about what size of crank to get, err on the side of shortness.
Last Word On How to Measure a Bike
If you still don't understand how to measure a bike, you can always take your bike to a local bike shop for measurement. In addition, there are some great tutorials showing exactly what to measure and how to measure on YouTube. For a really informative tutorial on how to measure a bike you can watch this video: