How To Measure A Road Bike Frame

If you’re looking to buy or rent a road bike, be it new or used. You need to make sure that you know how to measure a road bike frame. If bike measurements do not fit you well, let’s just say there will be a lot of struggles for you. If you’re planning on getting a bike, the first thing you need to do is to get the measurements of the bike frame. 

To find the right measurement of your road bike frame, you will need to measure the top tube, the top tube is the horizontal tube that is connected to the road bike handlebars. You will also have to measure the seat tube, seat tube is the vertical tube that is connected to the seat of the bike. Now get a measuring tape and measure these in cm. We will explain it in detail, to read more scroll down. 

Here are four easy steps in detail so you don’t miss out on any step and make a wrong measurement. 

Step 1: For accurate measurement the top tube and the head tube should be in a straight line

Take a measuring tape and reach over to the frame from the handlebar to the other side, then take measurements of where the top meets. 

Step 2:  Now take measurements starting from the headtube to the handlebar

Now you have to make sure that this length is exactly the same as the top tube measurement. 

Step 3:  Measure the seat tube height

For road bikes, the seat tube measurement should be somewhere between 74 and 75 cm, and for Mountain bikes, it will be around 73 to 74 cm. 

Step 4: Measure the FRA or rear axle and the front axle distance

The rear and front axle is the place where you would want to mount your bike stand or training wheels. It should be somewhere around 26 inches to 29 inches long. This distance is also known as FRA. 

How To Measure A Road Bike Frame In Cm

To Measure a road bike or any bike you will need a tape measure, a level, and a pen and paper to measure all the points of the bike. So you can buy it if it fits you perfectly. 

Length:

The length of the top tube till the saddle should be somewhere between 97-100 centimeters for females and around 102-122 for males. The top tube of the bike should be at least 20 cm longer than the saddle. If the top tube is not bigger than the road bike saddle, your leg muscles and back will be fatigued and ruin your posture. This can lead to many other ailments, so choosing the perfect fit for your road bike is very important. There should be enough space in the tube for a water bottle or you want to add an extra storage bag for holding your personal belongings. 

Height: 

Make sure that the height is not too high or too low for your body. If the height is too high, you will have a very hard time reaching the pedals from various angles and if it is too low then it will affect your posture. Usually, women go for lower bars and men go for higher bars due to the height difference. 

Seat post:

The seat post is an essential part of any bike, it connects the saddle to the bike. When it comes to the sizing it is clear that a taller rider needs a higher post whereas a shorter rider needs a lower one. 

The right length of a seat post is between 90 to 115 cm for females and 110 to 130 for males. 

Bars:

There are bikes that have higher bars, typically the length for a male is 124 to 156 cm, and it is said for women to get a bike with a head tube length of 125 cm or in the range of 115 to 136cm. It all depends on the type of bike you want. 

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How To Measure Yourself For A Road Bike Frame

Road bike frames are measured in two ways, one by top tube length and the other by seat tube length. 

The horizontal distance from the middle of the head tube of the bike is known as the top tube length of the bike, it is usually where the fork is attached to the frame of the bike. This measurement is expressed in centimeters and it establishes the overall performance and handling of the bike. 

The seat tube length is the length from the middle of the bottom bracket, in simple words the place where the pedals are attached to the frame of the bike. This measurement is also expressed in centimeters and it is a very important factor that helps determine the right frame size for you or your loved one. 

To Measure yourself and the length of the inseam, the steps are mentioned below. 

Step 1: 

First of all, stand up straight in a good posture. You have to place your foot on the ground with your heel. Now mark the height where it touches the floor. Repeat the same process with your other side and take out an average between them so you can determine how tall you are without your shoes. 

Step 2:

Now measure your chest over your nipples and for females measure over your bra, the one that you’ll be wearing while riding a bike. Keep your arms in a relaxed T position and slightly bent. 

Take these measurements while wearing clothes and jerseys that you wear while cycling. Make sure to get the measurements on the garments so they are accurate. 

Step 3: 

First, you measure from the inseam at the groin and up to the nipple height, after that repeat the same procedure on the other side and take out an average between both measurements. 

You can measure any leg, be it left or right around the thigh and just below the hip. Then take the measurements from the hip to the narrowest part of the thighs. 

Measure Height Without Shoes 

You will have to stand against a wall with your back aligned with the wall. Legs should be in a stable position. Not too wide apart and not too close. Just the right distance apart. You need to stand up straight in a correct posture, so the measurements are accurate.

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How To Measure Trek Frame Size

Inches	CM	Inches	Trek Bike Size
4’10” – 5′ 2″	148-158	13-14	XS
5’2″ – 5′ 6″	158-168	15-16	S
5’6″ – 5′ 10″	168-178	17-18	M
5’10” – 6′ 1″	178-185	19+	L
6’1″ – 6′ 4″	185-193	21-22	XL
6′” – 6′ 6″	193-198	23-24	XXL

Also Read: Bike Size Chart: Ultimate Guide For All Bikes 

Example of Trek Road Bike

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How To Measure A Specialized Road Bike Frame

Your Size – Inches	CM	Specialized Bike Inches	Specialized Bike Size
5 feet 1 inches –    5 feet 4 inches	155-163 cm	46-48	XXS
5 feet 5  inches –   5 feet 6 inches	165-168 cm	50	XS
5 feet 7  inches –   5 feet 8 inches	170-173 cm	51-52	S
5 feet 9 inches –  5 feet 10 inches	175-178 cm	53-54	M
5 feet 11 inches-  6 feet 0 inches	180-183 cm	55-56	L
6 feet 1 inches –  6 feet 2 inches	185-188 cm	57-58	XL
6 feet 3 inches – 6 feet 6 inches	191-199 cm	60-63	XXL

Example of Specialized Road Bike

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How To Measure Vintage Road Bike Frame

M	Inch	Leg Length	Size CM
1.47m -1.55m	4’10” – 5’1″	65cm – 69cm	46 – 48 cm
1.52m – 1.60m	5’0″ – 5’3″	67cm – 71cm	48 – 50 cm
1.57m – 1.65m	5’2″ – 5’5″	70cm – 74cm	50 – 52 cm
1.63m – 1.70m	5’4″ – 5’7″	72cm – 76cm	52 – 54 cm
1.68m – 1.75m	5’6″ – 5’9″	75cm – 79cm	54 – 56 cm
1.73m -1.80	5’8″ – 5’11”	77cm – 81cm	56 – 58 cm
1.78m – 1.85m	5’10” – 6’1″	80cm – 84cm	58 – 60 cm
1.83m – 1.91m	6’0″ – 6’3″	83cm – 86cm	60 – 62 cm
1.88m – 1.96m	6’2″ – 6’5″	88cm – 91cm	62 – 64 cm

Example of Vintage Road Bike Frame

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How To Measure A Cannondale Road Bike Frame

Feet and inches	CM	Size – CM	Cannondale Road Bike Size
5.0-5.4	48 cm	152-162	XXS
5.4-5.6	50 cm	162-166	XS
5.6-5.7	52 cm	166-170	S
5.7-5.10	54 cm	170-178	M
5.10-6.0	56 cm	178-182	L
6.0-6.2	58 cm	182-188	XL
6.2-6.4	60 cm	188-192	XXL
6.4-6.7	63 cm	192-200	XXXL

Example of Cannondale Road Bike

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What you’ll need to measure a road bike frame?

Being a cycling enthusiast is all fun and games until you start thinking about getting a new bike and the right height of the bike. To understand the right height of the bike, you’ll need to measure the frame of the bike. So, here we have mentioned the things you’ll need to measure the bike. 

Tape measure:

Almost all households have a measuring tape lying around somewhere and if not you should definitely invest in a good measuring tape. Measuring a bike with measuring tape is the most accurate way to measure. 

Level: 

A level will help to see if the bike is standing up straight or not. This is a very important part of measuring a bike. 

Pen and paper:

When you start measuring the bike, you will take multiple measurements of different parts of the bike, this is why you will need to write the measurements down. 

Bike:

This is the main character of our story. To Measure a bike you will need a bike. Right? Make sure you have taken all the extra accessories off of the bike. 

How to measure a road bike frame geometry?

Measuring bicycle frames are essential for determining the right size frame for you or your family. To measure the right frame size you will need multiple measurements, which include stem size, seat post length, reach, and wheelbase. Let’s explore these in detail:

Stem size:

Stem size is something that refers to how forward or backward it is placed from the center of the bike’s frame. 

Seat Post Length:

The seat post length is measured from the top of the seat post to the center of the bicycle frame. The height of the frame must be measured using this measurement in order to make sure that the rider can comfortably reach the pedals and maintain a proper pedal stroke.

Reach:

The horizontal distance from the handlebars to the center of the bike is known as reach. The riding position and the comfort of the rider are dependent on this for the comfort and correct riding position. If the reach is longer the rider will have an aggressive riding position that can be ideal for racing and short distance. If the reach is shorter, the rider will have a relaxed posture that is good for long distances and comfortable riding.

Wheelbase: 

The wheelbase of the bike is the horizontal distance between the rear and front wheels. The measurement here is crucial for the handling and stability of the bike. A wheelbase that is wide will give more stability and high speed to the rider. Whereas the shorter wheelbase will make the bike more responsive and nimble. 

How to measure stack and reach in a road bike?

To Measure Stack and reach, measure the bike from the center of the bottom bracket to the top of the clamp on the straight handlebar and then multiply it with the digit 2.

The stack is how high the head tube of your bike sits, above the saddle of your bike. So what is preferred is having lower numbers with smaller bikes and larger numbers with taller bikes. 

Reach is measured from the point where you are able to touch or grip the hoods or under them to back to the axle where the front wheel meets comfortably. 

Read More How To Measure Hybrid Bike Frame Size – Chart

How to check road bike frame size?

When you think of buying a bike, and generally wonder how to measure the size of your road bike, you go and check the bike retail shop or visit the online store and contact customer service and directly ask about the bike frame size. 

If the bike is from an older version then you will have to do some work on your own. Let’s take an example and explore it a little. Let’s just say you need an 18-inch bike. But while reading the reviews you saw that they offer two different sizes one has an 18-inch frame and the other one has a 20-inch. So, how will you know which one fits you perfectly?

For that, you will need to measure yourself from head to toe and then divide your height by 2. For example, if you are 72 inches long, divide 72 by 2 which is equal to 32 inches i.e. you will need an 18-inch bike. This is one of the simplest ways to determine the right road bike size.

How do I choose a road bike that fits me correctly?

If you are investing your money in an off-the-rack bike, then you should probably measure yourself. So, you know exactly the length of your inseam and your height. Store employees usually know the right size chart for whatever height you give them. But if you have trust issues then you might also want to do your research. 

If you don’t want to get into all the hassle, then you can just get a bike that has an adjustable frame. Bikes like Cannondale, cyclocross, Trek, Giant’s Defy, or Specialized models. Most of these bikes have adjustable handlebar seats that can be adjusted. 

Conclusion

In conclusion, just like not having the right fit of shoes can cause you to be very uncomfortable and in pain, not having the right bike size will cause pain and damage. If you want comfortable and safe riding you need to get the right frame size for yourself. So if you’re still wondering how to measure bike size. Then you need to know the right measurements including height, length, bars, and seat post. 

Measuring yourself on your own can be difficult to get someone to help you to get the most accurate measurements. One measure can go a long way, this is not something you will have to do every time you ride a bike. You just need to know the right bike size and how tall you are. We have mentioned the road bike frame size chart.

FAQ’s