The manufacturing companies offer bicycles with frames of different sizes. Just like for clothes, each size covers a broad spectrum of body types. They arrive in a whole series of sizes to satisfy almost all human body structures.
Let’s start with an introduction that allows us to understand what the size of a bicycle is. This reasoning also applies to articles concerning racing bikes, mountain bikes, and gravel bikes.
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Imagine having to create frames with all customized dimensions based on the customer’s build. It would be impossible to propose on an industrial scale. And it would have such exorbitant costs as to make the sale unproductive. For this reason, the buyer will choose or seek the advice of the ideal size.
The size, or frame size, is nothing more than the actual size of the frame. It comes with different tube lengths to reflect the body structures. Unfortunately, each manufacturer uses its system to show the size of the various models. Let’s see them.
Table of Contents
- Bike Size Guide for Men
- Bike Size Guide for Women
- Bike Size Chart for Kids
- Why is size so important?
- Methods for Calculating The Bike Size
- Construction of the Bike Frame
- How to Calculate The Measurements of The Bike frame?
- Types of Bike Size
- Bike Size Calculation
- Custom or not?
- Why Are Carbon Bikes So Expensive?
- Aluminum-Frame vs Carbon Frame
Bike Size Guide for Men
To demand a good bike for men, choose the model that best matches your morphology. Generally, a correct size leaves a brief space between the crotch and the sidebar of the bike.
It displays the size of a bike in the store. They choose in three stages:
- the calculation of the frame size,
- the saddle height change,
- adjusting the handlebars.
The basis for calculating the height of the frame depends on the height of the person and their crotch. This measurement must be done with shoes on, to reproduce the exact size of the rider ready to go. The calculation formula depending on the type of bike. Here are the calculations to be made according to the bikes to determine the size of the frame:
- VTC: Inside leg length x 0.22
- Racing bikes: Inside leg length x 0.65
- City bike and electric bike: Inside leg length x 0.66
Making no calculations, there are standard size reports that allow you to know the size of the bike frame:
Men’s Hybrid Bike Size Chart
|Rider Height (cm)||Men’s Height (inch)||Inside leg (cm)||Inside leg (inch)||Bike Size||Bike Size (inch)|
|147cm-152cm||4’10”-5’0″||66cm||26″||XS||13” – 14″|
|152cm-160cm||5’0″-5’3″||69cm||27″||XS, S||14” – 15”|
|160cm-170cm||5’3″-5’7″||71cm||28″||S||15” – 16″|
|170cm-175cm||5’7″-5’9″||76cm||30″||M||17″ – 18”|
|175cm-180cm||5’9″-5’11”||79cm||31″||L||19” – 20″|
|180cm-188cm||5’11”-6’2″||81cm||32″||L, XL||20″ – 21”|
|188cm-196cm||6’2″-6’5″||86cm||34″||L, XL||21” – 22”|
|196cm+||6’5″+||91cm||36″||XXL||23″ – 24”|
Men’s Racing Bike/Road Bike Size Chart
|Rider Height||Crotch||Frame size|
|155 – 165 cm||72/76||48 – 51 cm|
|165 -170 cm||76/79||51 – 53 cm|
|170 -175 cm||79/83||53 – 55 cm|
|175 – 180 cm||83/86||55 – 57 cm|
|180 – 185 cm||86/90||57 – 60 cm|
|185 – 190 cm||90/93||60 – 62 cm|
|190 – 195 cm||93/97||62 – 64 cm|
|195 – 200 cm||97/102||64 – 66 cm|
Men’s Mountain Bike Size Chart
|Rider Height||Crotch||Frame size|
|155 – 165 cm||61/66||35 – 38 cm|
|165 – 170 cm||66/71||38 – 41 cm|
|170 – 175 cm||71/75||41 – 43 cm|
|175 – 180 cm||75/80||43 – 46 cm|
|180 – 185 cm||80/84||46 – 48 cm|
|185 – 190 cm||84/92||48 – 53 cm|
|190 – 195 cm||92/97||53 – 56 cm|
|195 – 200 cm||97/102||56 – 58 cm|
Men’s City and Electric Bike Size Chart
|Rider Height||Frame Size|
|150 – 165 cm||43 – 46 cm|
|165 – 175 cm||46 – 51 cm|
|175 – 185 cm||51 – 56 cm|
|190 – 195 cm||56 – 60 cm|
Men’s bike settings
To test the height of a saddle, just sit on it with your heels on the pedals in the inferior position. If the leg remains straight and slightly bent, the saddle is well adjusted. The saddle leans 0.5 to 1 cm forward only in men. In women, the setting is reversed.
The hanger is at the correct height if the angle formed between the hand resting on the top of the hanger and the torso is at a right angle. However, it is still necessary to leave a little slack on the forearm to absorb the shocks. The width of the hanger is approximately the width of the shoulders between 40 and 42 cm.
Bike Size Guide for Women
Women’s Hybrid Bike Size Chart
|Rider Height (cm)||Women’s Height (inches)||Frame Size||Frame Size (inches)||Frame Size (cm)|
|148cm to 158cm||4’10” – 5’2″||X||13″ – 14″||33cm to 36cm|
|158cm to 168cm||5’2″” – 5’6″”||S||15″ – 16″||38cm to 41cm|
|168cm to 178cm||5’6″ – 5′ 10″||M||17″ – 18″||43cm to 46cm|
|178cm to 185cm||5’10” – 6’1″||L||19″+||48cm+|
Women’s Road Bike Size Chart
|Rider Height (cm)||Women Height (feet & inches)||Frame Size||Frame Size (cm)|
|147cm to 155cm||4′ 10″ to 5′ 1″||XXS||44cm to 46cm|
|155cm to 160cm||5′ 1″ to 5′ 3″||XS||47cm to 49cm|
|160cm to 165cm||5′ 3″ to 5′ 5″||S||50cm to 52cm|
|165cm to 172cm||5′ 5″ to 5′ 8″||M||53cm to 55cm|
|172cm to 180cm||5′ 8″ to 5′ 10″||L||56cm to 57 cm|
Women’s Mountain Bike Size Chart
|Rider Height (cm)||Women Height (feet & inches)||Frame Size||Frame Size (inches)||Frame Size (cm)|
|148 to 158cm||4′ 10″ to 5′ 2″||XS||13″ – 14″||33cm to 36cm|
|158cm to 168cm||5′ 2″ to 5 ‘6″||S||15″ – 16″||38cm to 41cm|
|168cm to 178cm||5′ 6″ to 5′ 10″||M||17″ – 18″||43cm to 46cm|
|178cm to 185cm||5′ 10″ to 6′ 1″||L||19″+||48cm+|
General Women’s Bike Size Explained:
Generally, the choice of the size of a women’s bike varies little from a men’s bike. The main morphological differences between man and woman are the width of the basin and leg length. This results in some differences in the saddle. The pelvis and the saddle are wider. And women have longer legs than men. Often, it is unnecessary to adjust the saddle too high. The saddle straightens forward 0.5 to 1 cm that is opposite to the male setting.
It modifies the bikes depending on the type of road to be taken:
- MTB: the structure is not modified whether for a man or a woman;
- Racing bike: besides the horizontal sidebar position for men, cycle specialists offer women’s bikes with less power and endurance demands.
A saddle for women has unique characteristics from that of a man. It must mainly be wider (especially in the back) to be comfortable, even during long rides. Bikes with central slits are a popular choice for the comfort and protection provided to the perineum.
The female anatomy differs from the male and in order not to experience that unpleasant pain in the lower back, even after short rides. It is necessary to choose the correct saddle. To be sure of the choice, try different types, and choose the ideal saddle also based on the use that you will do with the bicycle. There are several models for off-road racing or travel bikes.
The size of the handlebar (usually 38 – 36 inches for racing bikes) is to be evaluated based on the width of the shoulders. The narrower they are, the shorter the handlebars must be for stability and comfort. The gear levers and the brake are sometimes big and little adapted to our smaller hands. By opting for oversized levers, you will risk not being able to brake promptly in case of need.
What makes a bicycle for women more expensive than other types? It is the frame. It makes every bicycle different from the other, not just women’s ones. Materials and construction typology have their part. But if we talk about high-end models, it is above all the geometry that gives an important imprint to the behavior of the frame.
For convenience, we consider the body of a woman regarding the bicycle, as well as a small man and a child. From a general point of view, this speech can also be acceptable. But if you go into the details, some differences must be considered, especially if we are talking about competitive spirit where everything is enhanced (even the defects) different from the speech for a bike walking. But then, it always matters how much time you spend in the saddle.
|Type of Road||Type of Bike|
|City (ecology)||city bike or Dutch bike|
|Assisted with pedaling||Electric bicycle|
|Speed competitions||Racing bike|
|Transport of a child||Triporteur|
|Driving Type||Type of Bike|
|Handy & Fun||Short Bike|
|Comfort||Type of Saddles|
|Saddle||Wide saddle reinforced with gel|
|Shock Absorbers||Shock absorbers under the saddle to reduce shocks|
|Tires||Type of Tires|
|Mountain Biking||Wide and studded|
|VTC||Large grooves and small studs|
|Accessories||Level||Type of Accessories|
|Security||Mandatory||Bell, front and rear lighting, reflective bar on the wheels (reflectors)|
|Security||Optional||Helmet, reflective vest|
|Maintenance and repair||Pump, inner tube, tire iron, anti-puncture spray|
|Comfort tool||Gel covers saddle, mudguard, wardrobe, kickstand, luggage rack|
|Child transport||Child seat and helmet|
|Transport of objects||Front, side or rear pannier, basket|
Women’s Bike Settings
The first thing to consider choosing the right bike is the size of the frame that must be calculated based on the height, the size of the bust, and the length of the limbs. Choosing the wrong frame or fitting oversized components means risking experiencing annoying pain in the knees, neck, and back.
To be sure of the choice, make three considerations. To identify the approximate size of an ideal frame, it is necessary to know the size of the crotch that is the length between the pubic bone and the heel. Once you know this size, you can identify the suitable frame.
We can make an approximate measurement of the size of the bike with a simple test. Before buying any bicycle leaning against a wall, adjust the saddle, and get on the bike. Then, straighten your leg by resting your heel on the pedal when it is in the lowest position. The leg must be straight but relaxed and not tensed. Then hold the handlebar. Do you feel comfortable and at ease? If the answer is yes, you have probably found the correct size of your frame.
If your body distance from the handlebars requires you to over-stretch your arms, the frame is probably too big for you. If you cannot straighten your arms and you feel you are destroying the handlebars, then the frame is too small.
Sometimes, a frame may seem of an unsuitable size. But if you are unfamiliar with bicycles, get advice from a more experienced friend or a trusted dealer. You will more easily notice the inadequacy or not of a component. Alternatively, there are biomechanics experts who can adjust the position of the saddle and the handlebars. We advise you with more professional analyzes of your measurements.
Bike Size Chart for Kids
Choosing the right bike for your child remains difficult. For a small cyclist, consider the factors such as assessing their level, calculating it, and making sure they are comfortable on the model. It is also crucial to equip it to ensure its safety (wearing a helmet is compulsory for children under 12).
|Age (Years)||Wheel Size||Height (inch)||Height (cm)|
|2 – 3||10″||2′ 11″ – 3′ 5″||88 – 105|
|3 – 5||12″||3′ 3″ – 3′ 8″||98 – 112|
|4 – 6||14″||3′ 5″ – 3′ 10″||105 – 117|
|6 – 7||16″ – 18″||3′ 8″ – 4′ 2″||112 – 127|
|7 – 9||20″||3′ 10″ – 4′ 6″||117 – 136|
|9 – 11||24″||4′ 2″ – 4′ 9″||127 – 145|
|10 – 12||26″||4′ 6″ – 5′ 0″||138 – 154|
|11 – 14||14″||4′ 10″ – 5′ 6″||148 – 168|
|12 – 15||14″-17″||5′ 0″ – 5′ 8″||154 – 174|
|13 – 16||17″||5′ 3″ – 5′ 10″||160 – 178|
For the kid to feel good about cycling, he should neither be too small nor too big. It is necessary to replace the bicycle as soon as it becomes too small. He could, for example, recover the cycle of his big brother or his big sister. The size of the bike depends on the diameter of the wheels.
Bike size is usually expressed in inches, represented by the acronym. This size estimates the diameter of the wheels.
Children’s bikes settings
On children’s bikes, they design many aspects to help the child in his learning:
- The frame: the younger the child, the lower the frame should be and centered to allow the child to climb on it more easily and move around.
- The fixed gear: the wheel stops turning when the pedals are no longer operated. It is a safety measure for a child who is not yet familiar with the brakes.
- Real tires: allow the child to better understand when to remove the small wheels.
- Speed: to familiarize the child with changing gears and make it easier to ride on hills. A children’s bicycle can incorporate up to six speeds.
- Chain locked in a guard: the chain should not come into contact with the child’s fingers and feet. The major problem with the chain is that it gets caught easily in the laces.
- Saddle adjustable and without tools: easily adapts to the developing size of the child.
- Small wheels: to facilitate the evolution of the small cyclist. The small wheels removable by hand are preferable.
Why is size so important?
Cycling is a science, especially for the tensile forces involved. The geometry of a bicycle frame is decisive. The comfort of the seat, the manageability, and the effectiveness are transformed into a driving force. It has a strict effect on the geometry of the frame.
It includes the dimensions and the seat if these two parameters are not calibrated to your height. According to the intended use, you will risk incorrect postures, premature fatigue, and pain. Especially on children’s bicycles, it is essential to choose the size to ensure maximum safety.
It is easy to say bike, but no model fits everyone. As with clothes, knowing the measurements is essential for racing bikes to buy the right model for us. And as with clothing, the measurements of racing bikes and frames can also vary.
There are two methods to show the size of the bike and the frame: the international system, expressed in centimeters that is more suitable for racing bikes, and the Anglo-Saxon system, in inches, more frequently used for mountain bikes. The frame size, expressed in cm or inches, corresponds to the length of the bicycle seat tube (AB).
Methods for Calculating The Bike Size
Choosing the size of the bike that best suits our body is the most crucial aspect to consider when we decide to make a new purchase. Choosing the right frame size for a new bicycle has a decisive influence on the future use we will make of them. An incorrect choice of frame size can cause obvious discomfort in using the bike. It can also cause physical problems such as back pain, various pains, tingling.
The advice, when choosing the size of the bike, is to rely on competent personnel. In this way, we identify the right side of the frame suitable for our physique with certainty. The best solution for people who use the bicycle intensively and want to be sure not to make a mistake in choosing the frame is to pay a visit to an excellent biomechanical.
For people who do not want to spend money and time on a biomechanical visit, there are various formulas and tables. We use precisely these numbers to choose the size of the bike independently.
These formulas do not provide the best result. The variables that come into play in choosing the size of a bicycle frame are many. These tables and formulas provide a general sign with which to orient yourself.
- Center-center horizontal tube: it is measured by setting the zero of the meter on the virtual intersection between the horizontal tube and the seat tube. It is available to the run-up to the intersection, also virtually, between the horizontal tube and the steering head. Usually, this measurement is expressed in centimeters;
- Center-center seat tube: they fix the meter on the axis of the bottom bracket. It can run-up to the virtual intersection of the seat post with the top tube. Also expressed in cm, in racing bikes, it is usually identical to the top tube. The calculation of the frame size is strictly linked to the positioning on the saddle.
- Center-end seat tube: start from the bottom bracket axis and measure to the end of the entire seat tube, where the seat post is engaged. We can express this measurement in cm but is often in inches. As it refers to the world of MTB that has an Anglo-Saxon derivation;
- International size: exactly with the clothes is indicated with a letter of XS, S, M, L, and XL. A comparison of sizes, again based on the height of the cyclist, can be varied.
The correct frame size is easy to determine. You need a spirit level and a tape measure. If you do not have a level handy, you can also use a fairly thick book.
Here’s how to do it:
- For optimal measurement, take off your pants and shoes depending on the cut. The pants can distort the result. The shoes increase your proper height.
- Place the level horizontally between your legs and exert a slight push upwards, as if you were on a saddle.
- With the tape measure, the distance between the top edge of the level/book and the ground. It is the length of your crotch.
Type of Assembly
Once you have selected the correct size, you are only halfway there. For a perfect ergonomic change, the bicycle must be adapted to your height. We recommend that you opt for professional assembly.
Choose the pro assembly for home delivery. And our professional mechanics will adjust your bike individually to your height. In case of delivery to the branch, you can take advantage of the comfort and technology of the Smart Fit body scan. It provides a complete measurement of your body. So, we can adapt the bike to your needs of even greater precision. People who prefer to do-it-yourself can choose the free option of basic assembly.
Construction of the Bike Frame
One of the thorniest questions that arise when buying a bicycle is how to calculate the correct measurements of the frame? They are one of the first factors of correct positioning, even if they must be accompanied by an adequate assembly of components such as saddle, handlebar stem, and cranks. Knowing roughly the most suitable frame sizes for us is not a complex operation. And in this article, we will see how to do it.
Below, you will find indications based on universally recognized formulas. But since each individual has his physiognomy and the biomechanics of cycling is science on which we carry research and studies out daily, do not limit yourself to taking for granted the values you have once read the following lines.
If you carry out an activity at an advanced amateur level and spend many hours in the saddle, you should contact a professional. The information presented below is valid for most cyclists and for most of the people who practice cycling.
Frame Measurement Systems
For the bicycle frame, we often hear of very different numbers to show the size. Two different systems are used: the International System (i.e. the metric one) and the Anglo-Saxon system. The first expresses the measure of a frame in centimeters and is used mainly in racing bikes, the second uses inches and is more frequently associated with mountain bikes, revealing their American origin.
Length of The Seat Tube
In both cases, we associate the size with the measurement of a single element of the frame itself as the seat tube (the vertical one). You will hear about a size 46 bike. Here, we refer to the length in centimeters of the seat tube, from the center of the bottom bracket to the center of the intersection between the seat tube and top tube. Or with a bike size 18, it expresses the same length in inches.
Often, we speak of sizes XS, S, M, L, and XL. This denomination taken from clothing is a convenient convention for the mass production of looms. In the latter case, even more than a custom-made bike, the components mounted on the bicycle are fundamental. A question will immediately come to mind. Which size is suitable for me? How do I know it? There are specific tables made by bike manufacturers that can allow you to test your size based on height and other parameters, but there is also a more scientific approach.
How to Calculate The Measurements of The Bike frame?
When calculating the size of the frame of a bike, they refer to the length of the seat tube. For bikes on the market, once the correct size of the seat tube has been determined, the companies design the frames by referring to some standard anthropometric ratios that are valid for most of the population:
- Crotch / Height = 0.47
- Trunk / Crotch = 0.76
- Arm / Crotch = 0.87
These measurements are valid for people who have no significant disproportion in their physiognomy. Otherwise, it will be necessary to think about the creation of a custom-made frame and therefore a more in-depth biomechanical analysis.
Formula to Calculate Bike Frame Size
In case you simply want to know which standard frame size is most suitable, you just need to know the length of your horse and based on this calculate the height of the post. The method we are describing to you is famous as the Hinault method as they introduced it in preparing the French sample in the 90s and is valid for traditional bikes, with the top tube parallel to the road surface.
The Height of the Saddle and the other Measures
After determining the measurements of the bike frame, we will need to adjust the saddle. Find a practical and empirical method that will be good for most cycle travelers, in the article how to adjust the position on the bike or even, in this case, use a mathematical formula: Hs = 0.855 x C
Other important measures that can be adjusted by fitting suitable components are:
- the saddle-handlebar distance (S)
- the saddle-stem offset (D)
- the retraction of the saddle
Here you can consult the tables below. We associate some ranges of horse measurement to some ranges to adjust the parameters described above. These parameters must also and be adjusted according to the type of cycling you practice. The saddle-handlebar distance will have to be slightly shortened if you want a more comfortable posture and the saddle-stem gap. In the case of performance research (racing bike), the opposite concept will apply.
Tip: Getting the frame size right is not enough!
Finding the size of the frame of your bike, or the size is essential but not sufficient. The same size could theoretically be suitable for people who are also very different from each other as they could fit different bike sizes to the same person theoretically.
It is because each manufacturer adopts different measures. When you get on the saddle many variables come into play, from the constitution and physical proportions of the cyclist to the riding style to the distances you want to tackle to the level of competition.
If you have not already done so, once you have chosen the size, contact a trusted dealer, perhaps an excellent biomechanical. It will be up to you to worry about all those minor adjustments that will make the bike perfect for you. You can adjust the height of the saddle, the wheels, the handlebar, and the cranks.
The alternative is to opt for a custom-made frame that adapts as precisely as possible to your measurements and needs. But be careful with this choice. Although adapted even in the smallest detail, it is not very flexible. In short, an initial advantage could have some side effects. Take this into account. Do not forget that even a standard frame, suitably adapted that can give you great satisfaction.
Test the size of the racing bike on the road
Do not settle for purchase on paper. You are still about to invest (whether small or large) so avoid risky or careless choices. Once you have defined the size and adjustments, ask the dealer for a road test that gets on the saddle and ride. Only in this way, you can test if the size is the perfect one for you.
Choosing a racing bike of the right size means not only pedaling more efficiently and with a greater feeling of comfort, but it also avoids the risk of muscle pain in the back. And if you are undecided between two frames, two different sizes of racing bikes, if in doubt opt for the smaller one. It will be easier to adapt to.
Types of Bike Size
City and travel bike size
Cycle tourism is an activity that engages the cyclist for several hours a day for several consecutive days (sometimes months). Unlike racing bikes, aerodynamics or speed is not the prerogative as stability or reactivity typical of the MTB. The frames of travel or urban bikes are characterized by a position in the saddle with an upright and relaxed back that allows you to pedal for a long time without overloading the lumbar muscles.
This characteristic has led manufacturers to create frames with a more closed angle seat tube. It is a tube that is perpendicular to the ground. It has meant that the seat is more comfortable and less aggressive than the racing bike and allows you to find the best compromise between comfort and pedaling efficiency.
For city bikes and touring bikes, the issue is more confusing as the houses use the system they prefer. Thus, you can use measurements in cm, inches, or international. As always, let’s take the measure of our horse and insert it into the formula: Crotch x 0.66 = size (in cm)
This value shows the height of the seat tube from the axis of the bottom bracket to the end of the tube, where the seat post exits. If the manufacturer shows the measurements only in inches, you will need to multiply the height of your horse by 0.259: 80cm x 0.259 = 21cm
As you can see, the measurement of the height of the seat tube calculated with the mathematical method happens almost in the middle between the 52cm and 53cm measurement.
Racing Bike Size
In racing bikes, it is easy to find the measurement relative to both the stem and the horizontal center-center, as they are often of the same length. If they are different, for example, as a 52 × 53 cm. The first number shows the length of the column, while the second shows the horizontal length.
For calculating racing bike size, there are two methods. The first method refers to the technical data provided by the manufacturers. It is based on the height of the cyclist.
And the second is a little more scientific. According to height, the method varies for different body sizes. Since each manufacturer uses different geometries, they design the bicycles according to their own technical and philosophical ideas. More than a real calculation, it is a sign, as the size tables are standardized and do not consider aspects such as the setting of the bike. It can be more racing design and with more nervous geometries. The build of the cyclist is not perfectly balanced that does not satisfy the needs of a more comfortable sitting for back problems.
What about the exact measurements? We will find out using the second method that is based on a mathematical model. It is more precise and allows you to have effective feedback. You can compare yourself with the real measurements of the frames, reported on the sites of the manufacturers.
This method presupposes a mathematical calculation, such as the methods we have seen for the verification of the change measures of the bicycle. The measurement taken indicates both the height of the seat tube cc and the horizontal cc. On the racing bike, these two measurements are identical.
Mountain Bike Size
For the mountain bike, it is practically all in inches and refers to the height of the center end seat tube. It is because MTB frames use sloping technology with the top tube continuing with a clear inclination towards the seat tube. The sloping construction technology increases the rigidity of the frame but makes it practically impossible to measure the horizontal tube according to the classical method. The classic length value, called virtual horizontal, is present and is indicated by the manufacturers.
Besides the wheel diameters, the setup of an MTB changes according to the discipline. An XC MTB will have more compact and nervous geometries than a Freeride one. In XC reactivity, for maximum traction, the best power transmission counts. Otherwise, in Freeride resistance, stress and downhill efficiency are more important. This results in a measurement difference between one model and another.
See more: types of bikes and how to choose
Bike Size Calculation
Almost daily, we receive requests regarding the right frame measurements. To indicate the recommended measures, we have prepared a calculation sheet in which to insert the cyclist’s measures to get the (indicative) size of the ideal frame.
The compressed file to download is in Excel format, an almost universal calculation program. When measuring the cyclist, it is important to respect the references shown in the figure within the same spreadsheet. The resulting measurements will accord with the drawing scheme that you find in the spreadsheet itself. In particular, we measure the stem center-end regarding a standard geometry with the top tube horizontal to the ground.
Take off your shoes and pants (the cut of the pants may affect the measurement). If you have a spirit level, place it horizontally between your legs upwards. It works the same way with a book. But in this case, lean against a door or a wall. And you will have your measuring tool parallel to the floor. Now, measure with the tape measure from the floor to the top corner of the level or book. The value just got is the length of your horse.
Calculate The Saddle Height
The height of the saddle is the most essential dimension to calculate. The biomechanical efficiency of pedaling depends on it. It is such a preponderant parameter that it will be treated specifically in a dedicated in-depth study. We will test the various cases and their consequences. For now, let’s just start looking at how to calculate it.
The mathematical formula for calculating the saddle height was available in the late 1980s by the French cyclist Bernard Hinault: Horse x 0.885. Before the mathematical formula developed by Hinault, it was common practice for cyclists and frame builders to calculate the saddle height with empirical methods. It could give a satisfactory result, but it resulted from common sense and experience based on scientific evidence.
- First method: it was simple. The cyclist positioned himself on the bicycle with the saddle down. He rose on his toes and they raised the saddle to touch the pelvis. So, the cyclist could touch the ground with his toes.
- Second method: the cyclist was available to stand on the side of the bike, and they raised the saddle until it reached the level of the side.
- Third method: it seems based on a more scientific system, involving the cyclist getting on the bike. Lower the right pedal at the bottom dead center of the circumference and then get up on the tip. They positioned the saddle under the pelvis, guaranteeing the cyclist the maximum possible muscular excursion while passing through the lower dead center.
Calculate the Saddle Setback
The saddle retraction shows the distance between the anatomical center of the saddle and the graft on the seat tube. It is obtained by plunging the first to the level of the second and measuring the light between the two points. Since it is engaged on the seat tube THAT is not vertical but inclined, this value will vary as the saddle rises or falls. It is then possible to act on the saddle stems to increase or decrease it.
This measurement strongly influences the next one that is the distance between the saddle and the handlebar. In reality, the backward movement of the saddle also affects the efficiency of pedaling, the excursion of the muscles during rotation, and weight management.
This last aspect is fundamental in a discipline such as mountain biking, where finding the right center of gravity is essential to avoid overturning uphill or downhill. You can act with your weight on the rear wheel, increasing grip without compromising smoothness.
We calculate the saddle setback with the following mathematical formula: saddle height x [cosine ((column tilt/(180 x 3.14))]
We know that it sounds worse than the baccalaureate math test. But it is not that hard. Let’s try to describe the coefficients.
- Svezzamento saddle: we calculated in the previous paragraph
- Seat tube inclination: means the angle described by the seat tube and from the ground. The range of options for this angle varies between 71 degrees and 77 degrees of inclination. The higher the inclination value, the more aggressive and aerodynamic position corresponds. Without using a protractor and plumb line, to measure the angle of your steering column, use this simple legend :
- Road bike: 75 degrees
- MTB: 73 degrees
- Cycle touring: 71 degrees
The lower the inclination values, the less retraction.
Calculate the saddle-handlebar distance
Profoundly influenced by the backward movement of the saddle that moves the support point of the ischial tuberosities, this measure changes the attitude we will have on the bike. It gives us a more aerodynamic or more relaxed setting according to the coefficient chosen.
As you can see from the drawing, the distance from the saddle to the handlebar is calculated by plunging the anatomical support point on the saddle and the center of the handlebar at the level of the horizontal tube (or virtual horizontal). To calculate this measure, we can use the following formula: bust x aerodynamic coefficient.
By aerodynamic coefficient, we mean a dimensionless value that allows us to obtain a measurement related to the type of set-up that we want to maintain on the bicycle. I can use the coefficients as follows :
- Racing bike: 1.11;
- MTB: 1.09;
- Bicycle touring: 1.07.
Calculate the Handlebar Saddle Offset
Since the cyclist is in a three-dimensional way on the mechanical vehicle, a single measure is not enough to define all the characteristics. So, after calculating the distance between the saddle and the handlebar, we have to calculate the height difference, called the offset.
The offset value directly affects the angle of the back once you get on the saddle. So, it is important to calculate it accurately, especially if you plan to spend several hours there. The gap is identified by taking the position of the ischial support on the saddle as a reference point, for which we will have:
- Positive difference: saddle higher than the handlebar means greater aerodynamics;
- Negative offset: saddle lower than handlebar means more upright position.
We calculate the handlebar saddle deviation with the following formula:[saddle height x (breast (seat post tilt / (180 x 3.14)))] – [handlebar excursion x breast x 1.308]
Calculate the Length of the Cranks
The length of the cranks is usually a parameter that is never touched. Even when you buy a new bike, pay attention to this value. In reality, the size of the cranks on the market varies from a minimum of 165mm to a maximum of 180mm. Although there are cranks up to 200mm long, it remains relegated to the environment of biomechanics and prototypes. To understand the function of a crank arm, we must represent the crankset as a lever, as in the following drawing:
The crank arm is a lever, with the fulcrum (F) in the axis of the bottom bracket. The radius of the crown will be the resistant arm (Br), while the length of the lever will be the lever arm (Bl). When we apply a force (P) on the pedal, we must overcome the resisting force (R) that opposes the motion.
If the product of P x Bl, which is called the moment, is higher than R x Br. We can overcome the resisting force and put the crankset in rotation. It is easy to understand that if we increase the value of Bl, the value of P to be applied to overcome the resisting force will proportionally decrease.
So, by choosing a longer crank arm, the less effort we will have to make to pedal. Since it is a system of forces in constant balance, by choosing longer cranks, we will increase the force applied to the pedal but will decrease the pedaling speed. The circumference described by the pedals has a greater radius and takes longer to travel. In short, we can state that:
- Longer cranks: more force applied at the expense of speed (and pedaling frequency);
- Shorter cranks: less force applied at higher speed and pedaling frequency;
Now, the choice between more strength or more speed is a subjective aspect and depends on the personal choices and technical skills of each. However, there is a method to know the length of the cranks suitable for us. And to do this, we must use the length of our femur previously measured. Based on the length of the femur, we have:
- Length less than or equal to 300mm = 165mm cranks;
- Length between 301 and 400mm = 170mm cranks;
- Length between 401 and 480mm = 175mm cranks;
- 481mm longer length = 180mm cranks;
This comparison must consider the disciplines since in MTB shorter cranks are usually used to avoid contact with rocks or roots. If you look closely at an MTB of the same size, it will have a higher bottom bracket than a very special one.
Calculate the Width of the Handlebar
The width of the handlebar varies according to the type of discipline as an MTB handlebar will certainly be wider than a racing handlebar. The handlebar must allow a comfortable and safe grip without unbalancing the cyclist or forcing the clavicular joints. Usually, a very simple mathematical formula is used, which states that: Handlebar with = shoulder width.
Since the handlebars, especially with racing folds, are available in a range that covers from 400mm to 480mm, we need to find the measure immediately closest to our shoulder width. If you want to prefer a firmer grip or the possibility of having a greater lever arm during sprints or steep climbs, you can mount a handlebar with an immediately greater width.
Custom or not?
The choice of frame size is a delicate matter. It concerns male and female cyclists. For the athletes, there was a doubt whether to turn to a custom-made frame. The last solution was the one often followed by professional cyclists in the majority, at least until a few years ago.
It is not the optimal one. The opening of the market to the female world in cycling has led to the development of geometries made especially for athletes. The transition is gradual. But now, at least those at the top are becoming convinced of the goodness of the offer.
Some people go against the tide regarding the measures defined as women. They are the frame builders who work on made-to-measure sizes instead of standard sizes. It is often because of production needs and large numbers imposed by the big brands.
In the tailor-made logic, there are no differences between men and women. You simply have to build a frame that fits perfectly to the physique of those who have to ride it. You will consider the right proportions.
It is the strength of the historic Italian brands and the artisans of our house. It is being able to dedicate to each customer. On request, the time and personalization of the product not only based on the physical proportions. But it is also available on the type of commitment you want to have with the bicycle and its use. Also, you will consider the preferred routes.
Why Are Carbon Bikes So Expensive?
You are curious why carbon bicycles are so much more expensive than other aluminum bicycles, right? Why are carbon bicycles often present at the world’s top races? The main answer is that there are no materials that match carbon fiber in weight, and carbon fiber is most likely to be cast into an aerodynamic shape. And making a carbon-frame bike is a lot more difficult than an aluminum bike. Then join Giant International to find out how much lighter the carbon frame is than aluminum, the basic difference, and help you decide to buy a bike a lot easier.
Carbon fiber is a unique material and is made from individual fibers. These individual fibers are woven and glued together to form layers that can be shaped to form a variety of shapes. From there, a bicycle frame is extremely light but very stiff. Carbon fiber has an 18% higher weight ratio than aluminum and 14% higher than steel. The drawback of carbon fiber is that it is almost irreversible; If you have a bad problem, the frame may be broken and broken and cannot be repaired. Union Cycliste Internationale, also known as UCI, has issued a rule that requires a bike’s weight to be 6.8kg or more. This rule ensures the bike is strong enough not to break under normal racing conditions.
Aluminum is also a great material for a bicycle because aluminum frames can make thicker aluminum tubes for more rigidity and strength than steel. It’s not as light or as strong as carbon fiber, but aluminum is much less expensive to manufacture and can cost a race bike a lot. An aluminum bike cannot be welded like steel in the event of an accident, but aluminum can withstand a bit more abuse than carbon fiber before it breaks down. Aluminum is also an ideal material for a wheel as a damaged rim is less expensive to replace.
Aluminum-Frame vs Carbon Frame
Both types of frames have different advantages and disadvantages. When it comes to the lifespan of aluminum-frame and carbon-frame bicycles, aluminum-frame bicycles only have a lifespan of a few years, while carbon-frame bikes’ lifespan is unlimited. The carbon frame you can use forever if you never have an accident. However, it will be a rather heavy accident to destroy the rigidity and robustness of the carbon frame, and the aluminum frame may not be able to withstand it. Fortunately, damage to carbon frames can often be repaired, while re-welding or patching cracked aluminum frames is not safe. UV damage is essentially non-existent for reputable branded carbon frames.
The main difference between carbon and aluminum is vehicle weight and quality. The carbon frame is usually a bit lighter than aluminum and the quality of the carbon frame is better than the aluminum one because it is stiffer and more stable in difficult terrain. However, for the price, the aluminum frame is less expensive than the carbon frame.
So if you choose a carbon-frame bike, pay attention to the following areas: the area where the tubes are joined together, such as the seat and top tube, the bottom frame area, the top and bottom surface of the bike. the head tube, saddle, and saddle. Besides, like aluminum-frame bicycles, carbon-frame bikes need to clean the transmission, brake, handlebar, etc. And you can check for any cracks in the chassis or joints. Please!
And if you choose an aluminum bike, don’t worry because the bike’s quality has been proven to be appropriate and safe, but the price will be much cheaper. Also, remember to clean your bike as well as its frame to increase its longevity!
When you have to choose the size of the racing bike and the frame, do you prefer to test independently or rely on an expert? If you are approaching the world of cycling now, the best thing you can do is ask for advice from a trusted dealer or a good biomechanical. But if you want to know how to choose the size of a bike and frame and want to orient yourself before proceeding with the purchase, then there are some things you should know.
Starting with the correct bike size and the frame size is essential. In our experience as a biomechanist, we have seen many people suffer from back or neck pain from the wrong size bike.
We remind you that to find your position in the best possible way, you must contact a professional biomechanist with a degree in motor science or physiotherapy. They have anatomical skills and know-how the body moves on the bike.