How to Measure Bike Size

You will find tons of options for a high-quality bike, but this does not mean they are all the same. What works for others may not necessarily work for you. You need to know how to measure bike size so you can choose a ride that fits perfectly.

The right bike measurements will help improve comfort, efficiency, and speed. The most important part of the bike to measure is its frame, which must be compatible to your height. It is also crucial to consider the type of the bike, such as whether it is a road or mountain bike, as it will have a huge impact on sizing.

If you are clueless about measuring a bike, keep on reading, and we’ll share some tips. By the time you are finished reading, you will find a bike that can help unleash your best performance.

The Importance of Measuring Bike Size

To start with, let’s talk about the reasons why you need the right size for a bike. The things listed below will give you compelling reasons to not just choose any bike. Even if you are buying online, you need to know how measure a bike.

Correct Your Posture

The right posture is one of the most important for your comfort. You need to keep your back straight and maintain the right hand position. This is possible when you have the right size of a bike. Otherwise, you will be slouching your back and extending your hands more than necessary.

Minimize Fatigue

This is one benefit related to how the right bike size improves your posture. The more comfortable you are when riding a bike, the less fatigued you will feel, especially when you are conquering tough terrains.

Prevent Wrist Pain

If the bike is too small or too big for your size, your wrists will suffer from unnecessary strain. Your body will be putting more pressure on the wrists. This also means that it will be difficult to steer and control the bike.

Reduce Crash Risks

Using a bike with the wrong size makes you prone to crashes and injuries. This is because the bike is harder to control. It is not as responsive as it should be, compromising your safety. It is best to use a bike that you can maneuver comfortably.

Improve Efficiency

Proper bike sizing is also important to make your rides more efficient. This will make sure that you can make the most out of every pedal. This means that your efforts will not be put to waste as every stroke will propel the bike as you desire.

A Step-by-Step Guide on How to Measure Bike Size

The most important part of a bike that affects the right size to choose is the frame. Below is a quick step-by-step guide on how to measure the frame of a bike. We’ll discuss the most important parts of the frame you need to measure to find the perfect fit.

1.      Measure Your Height

One of the most basic things that you need to know when measuring a bicycle is your height. Most manufacturers will have bike fitting charts that recommend a specific model depending on your height.

To measure your height, remove your footwear and stand straight with your back against the wall. Mark the spot on the wall where the top part of the head is. Use a tape measure from the ground all the way to the part of the wall with the mark. Compare your height to different bike sizes.

2.      Measure Your Inseam

Your inseam is the measurement of your inside leg. This is the length from the floor to the crotch. A common mistake most people commit is to measure their jeans to know their inseam. To be more accurate, you need to measure your legs.

Stnad with your back leaning on the wall and your feet six to eight inches apart. Put a book between your legs, which will mimic the seat of the bike. Measure the length from the top of the book to the floor, and this is your inseam.

3.      Refer to a Bike Sizing Chart

Look at the sizing chart of the bike’s manufacturer and find the right measurement depending on your height and inseam. The tables below show a quick guide on general recommendations, although the exact figures might vary from one manufacturer to another.

 

MOUNTAIN BIKE
HEIGHTINSEAMFRAME SIZE
4’10” to 5’3″25 to 28″13 to 14″
5’4″ to 5’7″25 to 30″15 to 16″
5’5″ to 5’9″26 to 31″16 to 17″
5’9″ to 6′27 to 32″17 to 18″
6′ to 6’3″28 to 33″18 to 19″
6’1″ to 6’6″29 to 34″19″ +

 

ROAD BIKE
HEIGHTINSEAMFRAME SIZE
4’10” to 5′24 to 26″47 to 48 cm
5′ to 5’2″25 to 27″49 to 51 cm
5’2″ to 5’4″26 to 29″51 to 52 cm
5’4″ to 5’6″28 to 30″52 to 53 cm
5’6″ to 5’8′29 to 31″53 to 54 cm
5’8″ to 5’10’30 to 32″54 to 56 cm
5’10” to 6′31 to 33″56 to 58 cm
6′ to 6’2″32 to 34″58 to 60 cm
6’2″ to 6’4″33 to 35″60 to 62 cm
6’4″ +34″ +62+ cm

 

HYBRID BIKE
HEIGHTINSEAMFRAME SIZE
4’10” to 5’1″24 to 29″47 to 48 cm
5’1″ to 5’5″25 to 30″49 to 51 cm
5’5″ to 5’9″26 to 31″51 to 52 cm
5’9″ to 6′27 to 32″52 to 53 cm
6′ to 6’3″28 to 33″53 to 54 cm
6’1″ to 6’6″29 to 34″54 to 56 cm

Other Bike Fit Measurements You Need to Know

While your height and inseam are crucial numbers you need to know, they are not enough. For a more accurate fit, this section talks about the other essential measurements you need to know.

Standover Height

The bike stand over height is the distance between the top part of the top tube and the floor. Many manufacturers will indicate this in the technical details of their bikes. It is important that you provide one to two inches of clearance depending on the type of the bike that you are using.

Mountain Bike Standover Height

Lift the bike when measuring the standover height and add two inches of clearance. If your mountain bike has a full suspension, you can add less than two inches. Your weight will compress the suspension when riding, so you can add a lower clearance.

Road Bike Standover Height

The design of the bike’s tube will determine how much clearance is necessary. If you have a road bike with a straight top tube, add one inch of clearance. On the other hand, if you have a sloping top tube, you need a clearance of at least two inches.

Hybrid Bike Standover Height

If you are using a hybrid bike, you should add one to two inches of standover height clearance.

Reach

The bicycle reach measurement is an important number that determines how comfortable you are when sitting on a bike and holding the handlebars. It is the distance between your body and the bars. This is especially important in a mountain bike because you will be standing most of the time as you ride aggressive terrains.

When you feel like you are extending your arms too much when you are in a normal sitting position, this means that the reach is too long. On the other hand, when your arms are cramped, it means that the reach is too short.

Stack

While the reach is a horizontal distance, the stack is the vertical distance, specifically from middle of the top part of the head tube to the bike’s bottom bracket. It is expressed in millimeters or centimeters. This has a huge impact on the height of the bike.

For road bikes, it is good to have a short stack, which will allow you to lower the handlebar in case you want to be in a more aggressive riding position. Most beginners, on the other hand, prefer a higher stack, which will promote a more upright riding position.

Effective Top Tube

The effective top tube measurement is the horizontal distance between the seat tube and head tube. This is the same measurement regardless if your bike has a slope or top tube. It is important for fine-tuning your bike as you wish depending on the riding position you are most comfortable with. This is also one of the most important measurements for determining the front triangle of the bike.

Seat Tube Angle

Another important spec worth mentioning in this bicycle sizing guide is the seat tube angle. It is the angle between the horizontal line in the bottom bracket and the seat tube. It determines the position of the seat and has a huge impact on your comfort and efficiency throughout the ride. In most bikes, this angle will be anywhere from 70 to 75 degrees.

Head Tube Angle

Also called head angle, it measures how steep the steering axis is. It is the horizontal angle of the fork’s steerer tube. This is important as it determines how the front angle is sitting on your hands. If the angle is slacker, there is a lesser tendency that the bike will be pitching forward when you are riding on a steep terrain.

The head tube angle also affects the bike’s trail. If there is more trail, the bike is slower and the steering response is calmer.

Stem Length

As you measure bicycle sizes, another number that you should not miss is the stem length. This is the distance from the middle of the steerer tube to the middle of the bar clamp. It affects how roomy the cockpit of the bike is.

Aside from comfort and fit, the stem length is also important because it affects bike handling. If the stem is shorter, steering is snappier. If it is longer, on the other hand, steering is slower. Cyclocross racers prefer a short stem. Road cyclists, on the other hand, would rather go for a longer stem.

However, it is not enough that you have the right stem length for a more efficient and comfortable ride. Also consider the bar’s shape as it affects your hand’s position.

Saddle Height

You also need to know how to measure for a bike saddle to get the ideal fit. How low or high the seat is directly related to your comfort. To measure, start by determining the length of the saddle and find the midpoint. Once you know the midpoint, measure until the bike’s bottom bracket.

The right saddle height will put you in a proper position. When your foot is at the bottom of a pedal stroke, your leg must be slightly bent. It should reach an angle of up to 90% during a full extension. If you are not comfortable, adjust the saddle to the right height. Do it in increments of 2mm to prevent knee and leg strain.

Saddle Fore/Aft Position

Aside from the saddle height, it is also critical to measure the fore/aft position. To measure, position you bike against the wall. Measure the distance from the bottom bracket to the wall. Next, measure the length from the tip of the saddle to the wall. Deduct the first from the second measurement, and you will now know the saddle setback.

If you aren’t comfortable with the current saddle setback of the bike, loosen the seat fixing or binding bolt and slide the seat forward or backward depending on the position that you prefer.

Seat Tilt

Most bikes should have a seat parallel to the ground. The best way to measure the saddle tilt is to put a flat object on the top of the saddle, such as a wooden board. Put an inclinometer on the top and measure the tilt. You can also use your smartphone and download an app that will let you measure the tilt of a surface.

Bar Height

Also known as the saddle drop, this is the vertical distance from the grips to the floor. It is one of the most underrated measurements that affect bike handling. You can use a spacer or replace the handlebars if you like to change the bar height to suit your preferences.

A lower bar height will also lower your center of gravity. It puts more weight on the front wheels to increase traction. The bike will also be in a more centered position for better control, especially when you are climbing. However, you should also avoid getting too low as this will make the bike more difficult to control.

Differences in Bike Sizes

When it comes to bike measuring, take note of the differences in sizes between users. The most important is to know that men’s and women’s bike are made in different sizes. Whether you are buying a bike for men, women, or children, it is a good idea to have the opportunity to physically see the bike and see how it fits. This way, you will know if it is a good choice, and the seller can also make the necessary adjustments depending on individual needs.

Bikes for Men vs Women

Men are taller and bigger than women, so it is understandable that their bikes are also taller, longer, and heavier. Nonetheless, this does not mean that men’s bikes are exclusive for women and women’s bike are exclusive for men. For taller women, it is acceptable to use a bike for men. On the other hand, for smaller men, it is also acceptable to pick a bike with a women size.

For women’s bikes, you will find smaller frames, shorter crankarms, narrower handlebars, shorter stem, and smaller saddle.

Bikes for Kids

Obviously, bikes for kids are smaller to accommodate their height. It is also lighter, making it easy for them to maneuver the bike. For a general bike fit guide for children, refer to the table below.

AGEHEIGHTINSEAMWHEEL SIZE
2 to 430 to 39 inches12 to 17 inches12 inches
3 to 537 to 44 inches16 to 20 inches14 inches
5 to 839 to 48 inches18 to 22 inches16 inches
6 to 1042 to 52 inches21 to 25 inches20 inches
8 to 1250 to 58 inches24 to 28 inches24 inches
10+56+ inches26 to 30 inches26 inches

 

Conclusion

In sum, knowing how to measure a bicycle is one of the most important things buyers need to learn. Start by measuring your height and inseam, then match it to the size recommendations from the manufacturer. Bike sizes will also consider the different measurements of the parts of the bike, including standover height, reach, stack, effective top tube, and bar height. All of these things are crucial for choosing a comfortable and efficient bike that will help to unleash your best performance.