A comprehensive Tutorial for Bike Frame Size

What will you take into consideration when picking a bike for yourself? The appearance? The design? The technical element? Or the brand? But, do you know, what entails your deliberation most falls on the bike size, after all, I believe, you’re buying a bike for its practicality and functionality but seldom for putting it aside as a piece of decoration. To help you get a right bike, in this article, I’ll guide you on how to figure out the bike frame size that fits you perfectly.


What does a bike frame make up of?

When talking about bike frame, we are referring to tubes. Actually, the bike frame which locates at the central part of a bike is made up of 4 tubes, including the seat post tube, the top tube, the down tube and the head tube. The seat post tube is there to hold the saddle, the head tube joins the head parts, and the down and top tube connect the seat post tube and the head tube. In most cases, the bike frame size is printed on one of the frame parts. You can find the one that fits for you with its reference.


Why bike frame size so important?

Unlike other components on a bike that can be changed, you have no choice but to stick with the frame size of bike you bought. That is to say, if you made a mistake with choosing the right frame size of a bike, you would have to sell it and get a new bike with right size, which would be time-consuming and money-wasting. What’s worse, if you stuck to ride the wrong bike frame size, you would gradually develop back pain and knee pain. Therefore, it is crucial to get the size right in the very first beginning. But how to figure out the frame size of a bike that is right for you? Reading on to learn the measurements you need to do.


How many measurements you need to know?

We have known that to know the size of your bike frame is easy, but as to which size is fit for you, you have to figure out three things, the height, the inseam height and the reach, among them, your height and inseam height are of top importance. We talk about height quiet often, but the inseam height is seldom measured. Therefore, you need to know that inseam height refers to the distance from your crotch to the end of your pants. Inseam height is important because you have to make sure that your inseam height is higher than the stand-over height. The latter one is the height of the cross bar. If you want a comfortable riding experience, the cross bar should be kept 1-3 inches down from your crotch, or you will get hurt.

But what if you are between two sizes which all fits for you in terms of the above measurements? At this point of time, the measurement of reach is necessary. To measure it, you need to figure out your ape index which refers to your arm span compared to your height. There are two types of ape index, the positive one and the negative one. If you have positive ape index, your height is shorter than your arm span, then you have a short reach, if your ape index is negative, your arm span is greater than your height. For those who have short reach, if you are between two sizes, the bike with smaller frame size is better for you. But for those have long reach, the bigger one suits you more.


Bike-sizing systems for different kinds of bike

As of now, all bikes on the market fall into 3 types, the road bike, the mountain bike and the hybrid bike. Mountain and hybrid bikes share the same bike-sizing system while the system for road bike is unique. The following 2 charts show the bike frame size for road bike and mountain and hybrid bikes.


For whom is a woman-specific bike necessary?

Women are different from men in term of body size and structure. Generally, women have longer legs but shorter torso than men of same height, in such case, it seems reasonable to have women-specific bike be the sole choice for women.

But the reality is, when it comes to bike frame size, it cannot be decided simply by gender. Each of us is unique in terms of our height and body structure, you need to find yourself one that fits you perfectly regardless of gender. However, a woman-specific bike does have ground to be on the market. For women who are shorter than 5ft 5in (equal to 165cm), a woman-specific bike can match with them.

What’s more, such bike is also suitable for man who is short. But a problem is, you cannot generalize such measurement in every country because people in different regions hold different standards toward short and long. In a word, you are unique, your search for the bike frame size needs to be individual.


Suggestions on Choosing Right Size for Kid’s Bike

Factors we need to take into consideration when choosing the right bike frame size for kid are various. Remember, they are unlike those we think of when deciding the size for woman-specific bike.

The frame size for kids’ bike are measured with reference to three factors, their height, age range and wheel size. But we need to bear in mind, age range and wheel size cannot solely decide which frame size is right for kid, what is important is the measurements of height and leg. You have to base on the two measurements to decide the correct bike frame size.

Choosing the right bike frame size is of incomparable importance, some new riders forsake riding just because of their unpleasant riding experience arising from wrong frame size. But, in fact, riding is fun and relaxing. I don’t want such joy to be missing in your life. So, before handing out your money, make sure you have found a right one.


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