What Bike Size Should I Get?

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Buying a new bike can be an exciting experience, whether you are an avid rider or are just starting out with riding for fun or exercise. 

However, not all bikes are created equally, and you should do your own proper research before making any big purchases. Asking the right questions will pay off!

What bike size should I get? To find the correct-sized bicycle, take a few critical measurements of the rider and consult an expert if needed. These important measurements are:

• Inseam

• Stand-Over Height

• Torso and Arm Length

• Top Tube Length

Finding the correct size bike is critical to getting the proper ride when purchasing a new bicycle. A bike that is too small is hard to pedal; a bike that is too large can handle poorly and be dangerous to ride. 

Whether you decide to visit the local bike shop or order your new bicycle online, starting off knowing what size you need will make all the difference.

Read Also: Are Bicycle Pedals Universal?

The Importance of Proper Bike Fit

Finding a bicycle that fits your personal body correctly is critical for experienced and new riders alike. 

If you talk to any cyclists, they will tell you that proper bike fit is essential so that you can ride safely and produce the most power the most efficiently.

However, the most important part of finding a quality fit is that you can remain comfortable throughout your ride. 

With the right-sized bike, you’ll be able to ride the bike as long as you want and as hard as you want, while remaining comfortable.

Improper positioning can lead to overuse injuries that can hinder your riding abilities. Of course, the difficulty is that every person will vary in correct positioning, even factors like age, riding style, and physical attributes can affect this fit.

How Different Bikes are Sized

Depending on the style of bike you plan to purchase, the fit will vary. In fact, every style of bike is sized differently, and you will want to take this into consideration before making any final purchases. Some key sizing factors you will want to consider are:

  • Mountain Bikes – These come in the standard Small, Medium, and Large sizes that are generally the same across all brands. If you know you are small in one brand of mountain bike, you can almost guarantee that you are a small in other brands.
  • Road Bikes – These also come in standard Small, Medium, and Large sizes, as well as numerical sizes. The difficulty here is that different brands will differ in size somewhat drastically, and the number provided may not correlate to a common measurement across brands. This is when the importance of reading size charts and even trying the bikes in person can be very critical.
  • Hybrid Bikes – These tend to be a mixture of road and mountain bikes. They tend to have better sizing than the traditional road bikes but are not as universal as most mountain bikes are. Overall, they can be similar across brands but may still offer differences in size.

Read Also: Are Clipless Pedals Really More Efficient?

Important Measurements for Bike Sizing

As previously mentioned, there are several key measurements that you must take to ensure that you are getting the proper bike fit. 

You will want to complete these measurements as accurately as possible, asking for assistance as needed. Also, you want to write down these measurements as you go so that you can compare them to the size chart for any bicycles you are considering.

How to Measure Your Inseam

One of the first measurements you will need to take is your inseam which is important as it helps you establish a base height for your bike. 

This is also known as your inner leg measurement, which you may see listed on certain websites.

You will want to do this in completely bare feet and will also need a hardcover book, a pencil, and a tape measure.

To gather proper inseam measurements, you will need to:

  1. Stand completely upright, trying to stand as straight as possible. You will want to be near a wall.
  2. Straddle the book. You will want to place it between your legs so that the spine is pressed into your crotch area. This should be as if you are sitting on the saddle of the bike.
  3. You should position yourself so that the part of the book extending in front of your touches the wall in front of you. You will then use a pencil to mark the wall along the top of the book spine.
  4. You will then use your tape measure to measure from the floor up to the mark on the wall. This will represent your inseam measurement. You may want to do this a couple of times to guarantee that you are getting a proper measurement.

This inseam measurement determines the height of the bike that you are hoping to buy.

For most road bikes, you will need to be able to stand flat-footed over your back and have a few centimeters of clearance between your crotch and the top tube or crossbar of the bike. You will want to take this into consideration when measuring your final inseam.

Measure Your Torso and Arm Lengths

Your arm and torso measurements are also very important when choosing the right bike size, as they are critical when helping you select a bike that is the right length for you. Grab your tape measure, book, and pencil again and follow these steps:

Torso Measurement:

  1. Place the book between your legs again so that the spine is facing upwards.
  2. Measure from the top of the spine to the beginning of the V in your neck. This is the top of your breastbone.
  3. You will want to hold your tape measure vertical to take this measurement accurately. Do not lie the tape measurer flat against your chest.

Arm Length Measurement:

  1. Make a fist holding your arm out to your side, turn your hand so that your thumb faces the ceiling.
  2. You want to ensure that your arm is parallel to the floor.
  3. Measure from the endo f your collarbone to the middle of your fist, and this is your arm length measurement.

Understanding Stand-Over Height

When you begin researching bike measurements, one thing you will see is that most bike heights are referred to in terms of its stand-over height.

Stand-over height is the distance from the ground to the upper surface of the top tube of the bike. As mentioned, you will want to ensure your inseam measurement is between 2.5 cm and 5 cm greater than a bike’s stand-over height.

You will want to find your stand-over height in either bare feet or while wearing cycling shoes. To do this, you will want to make sure that you can straddle your bike with your feet flat on the floor. Each style of bike will have different stand-over height needs; these are:

  • Road Bikes – Most road bikes have a traditional straight top tube that is parallel to the ground, you will want to have approximately one inch of clearance between the ground and the tires when you lift the bike as if you are straddling it. For those road bikes with a sloping top tube, you should expect to have about two inches of clearance or more.
  • Hybrid Bikes – You will want to use the road bike guidelines if your hybrid bike is a city commuter. However, if it is not, you will not have to worry about the stand-over height.

    Many hybrid bikes have steeply sloping top tubes that you can step over easily and put your feet flat on the ground while you are seated.
  • Mountain Bikes – When considering a mountain bike, you will want a two-inch minimum clearance between the tires and the ground when being lifted. If you have a full-suspension bike, you can have less initial clearance because your suspension will compress under your weight once you are seated.

    The amount of clearance you have can vary greatly with mountain bikes because of the slope of the top tube, which is why stand-over height is not the only measurement you will want to consider.

Understanding Top Tube Length

The overall length of the bike is determined by its top tube length. This is the horizontal distance between the head tube or where the handlebar strut sits and the seat tube.

Calculation: For most road bikes, you can add your torso and arm measurements together and divide this result by two, then subtract six inches. This will give you your proper top tube length.

Many want to focus primarily on the stand-over height measurement but also knowing your effective top tube length is critical. This is often referred to as the ETT length. When you purchase a bike with a correct ETT, you will be able to fine-tune your upper body position with smaller adjustments later, more easily.

How to Fit Bikes for Women

When you purchase a woman’s bike, it is already adjusted to fit the differing height of women. For example, most women have proportionally narrower shoulders and longer legs compared to their torsos, unlike men. 

Most women’s bikes have narrower handlebars and shorter or more compact frame dimensions. However, some women do feel that men’s bikes work better for them while others opt to go with women’s bikes and prefer this fit.

How to Fit Bikes for Kids

While you may want to get a larger bike so that your child can grow into it, it is not a great choice to do so. 

You want to ensure that your child can ride the bike comfortably and knows how to position themselves properly. This is why you will want to do your best to find a bike that fits properly at the time of purchase.

Measuring Stand-Over Height

You will want to start by checking the stand-over height of the bike, doing similar to what you would do for an adult bike. You will need to take the top tube style into consideration and opt for two to four inches of clearance.

Proper Seat Height

Kid’s bikes are mostly designed so that they ride in a more upright position. Your child should be able to sit comfortably and see around them easily while gripping the handlebars with a slightly bent elbow. 

You should notice that their legs are slightly bent at the bottom of the pedal stroke. Overall, you want to ensure that your child is as comfortable as possible while riding.

Standard Size Guides

While each company will vary slightly, there are standard sizes that you can consider when choosing your bicycle. Below, I have provided a basic chart for Standard Road Bikes, Mountain Bikes, and Children’s Bikes. 

You can reference these charts for a basic idea on what size frame you may need for your new bike.

Standard Road Bike Sizes

Frame SizeRider HeightInside Leg Measurement
48cm5’1” to 5’3”27” to 29”
50cm5’3” to 5’5”28” to 30”
52cm5’5” to 5’7”29” to 31”
54cm5’7” to 5’9”30” to 32”
56cm5’9” to 5’11”31” to 33”
58cm5’11” to 6’2”32” to 34”
60cm6’1” to 6’3”33” to 35”

Mountain Bike Sizes

Frame SizeRider HeightInside Leg Measurement
Extra Small4’10” to 5’2”13.5” to 15”
Small5’2” to 5’6”16” to 17”
Medium5’5” to 5’10”17” to 18”
Large5’10” to 6’1”19” to 20”
Extra Large6’1” to 6’5”21”+

Children's Bike Sizes

Bike SizeChild HeightChild’s Age
12”89 to 102 cm3 to 5 years
16”99 to 117 cm5 to 7 years
20”114 to 132 cm7 to 9 years
24”130 to 160 cm9 to 12 years

Ensuring Ultimate Comfort and Performance

By following the basic guidelines previously laid out, you will be able to purchase a bicycle that fits your body shape and needs perfectly. 

If you are unsure if your bike fits your needs, you can always visit a local shop to learn more about the proper fit you need.

Consulting an expert in the area is a great way to ensure you get proper fit and do not subject yourself to unwanted injury. Sometimes the local bike shop costs a little more – but you may get the service you need to find the bike that fits you best.

You should never settle for a bike that is not comfortable. If you have a bike that arrives at your door that does not fit you properly, return it and find one that fits. 

If you do not receive a bike that fits you ideally, it will not be ridden, and you will miss out on a wonderful new pastime. Riding a bike that is uncomfortable can not only be difficult but can also be dangerous.

Sit on the bikes to get an idea of what feels comfortable. Even if you do not purchase a new bike from your local shop, go to the shop to get a better idea of the frame size that you need. 

You can always take this information along with the measurements you have recorded and find your perfect bike online easily.

Adjusting Your New Bicycle

Once you have your bike size and have purchased your bike, the work is not finished. While your bike fit may be great, there are still some customizations you should make to guarantee that you are having the most comfortable ride possible. 

If you have begun riding your bike and have noticed some discomfort, it may be time to make alterations to your bicycle for a better fit.

Some common signs of improper fit are knee pain, which can indicate improper saddle height, back or neck pain, which can be a sign that your handlebar reach is off. 

When you have a proper position, you should be able to maintain it throughout your ride comfortably. 

If you find yourself fidgeting in the saddle or you cannot find a comfortable hand position during your ride, you will want to readjust your bicycle.

Proper Upper Body Position

You will want to ensure that your upper body position is correct for comfortable riding. 

Aim for a riding position that gives you a modest amount of shock-absorbing bend in your arms, but you should never have to overreach to apply the brakes.

  • For road bikes, your torso should form a 45-degree angle with your hips and a 90-degree angle with your arms. You can always swap out the stem to bring your handlebars closer and lower strain.
  • For mountain and hybrid bikes, these angles are not as important, and riding positions are not as upright but tend to be more relaxed. When you ride mountain bikes, you will often spend more time out of the saddle, and your seated pedaling position isn’t as important.

Adjusting Your Bike Seat Height

You will want to have your seat height and position dialed in, which means you have the best chance of pedaling powerfully and efficiently.

To ensure you have a proper position in your seat, you will want to see a slight bend in your leg with your foot at the bottom of the pedal stroke. You should only reach about 80 to 90 percent of full leg extension.

If your legs are not positioned properly, you will want to adjust your seat height. This may differ for each bicycle but usually requires you to loosen the quick-release level on the seat post and raise or lower it as needed.

When to Consult a Professional?

While many can find their perfect bike by following these simple DIY measuring instructions, if you are an avid cyclist, you may want to consult a professional. There are actually individuals out there that can give you a complete professional fitting for your new bicycle.

This is especially important for those who may not fit traditional heights or sizes, as not all bodies are created equally.

Also, if you have old injuries that need to be addressed or even different length legs, this can be almost impossible to fit on your own. 

When comfort goes beyond convenience and is critical to your health, you will want to guarantee that you find the best fitting bike out there. Opting for professional help now can save you from injuries later.

If you already own a bike that in theory, should fit you, but you are dealing with pain, numbness, or tingling in your extremities, you will want to consult an expert. An expert can make small alterations to your bicycle to ensure a proper fit without the need to purchase an entirely new bicycle.

What Happens During a Bike Fit?

After following the previously laid out steps, you probably have an idea of what size frame you need. However, the bike may still not fit you properly and may need some simple adjustments. 

This is why most manufacturers have created bicycles that have adjustable components so that these bikes can fit more riders.

When you work with a trained bike fitter, they will know how to make these small adjustments so that each component works for your needs. During this, the professional fitter should do a basic interview with you and consider your personal history with bike riding. You should make sure to include any information about past injuries.

Most basic fittings will include a few key steps, including:

  • Setting clipless pedal cleats int eh correct orientation
  • Evaluating your shoes and insoles
  • Determining correct stem length, handlebar height, and handlebar width
  • Setting your seat height and fore or aft position

Most fittings take between one or two hours and can cost around $100, depending on where you have your fitting completed. 

You will want to consult with your bike fitter beforehand to see what all you need to bring and what to expect completely.

When to Have Your Professional Bike Fit

If you are hoping to begin bike riding, you should get your bike fit as soon as possible. Many wait until they are in discomfort before learning more about bike fitting, which can be dangerous. 

At the first sign of discomfort, you will want to get a proper bike fitting.

Your body may take a few days to adjust to these changes that are made during the fitting. However, in time, you should find that your bike rides are more enjoyable, and you are more comfortable throughout.

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