How To Measure A Road Bike Frame- 6 Steps

It’s important to know the size of your frame before purchasing a bike. The first thing you’ll need is a measuring tape or ruler.

You’ll also need to make sure that the bicycle is on its side and not resting on any part of the frame, which would cause an inaccurate measurement.

There are four measurements that will help you determine whether it fits within your height range:

1. The top tube length
2. Top tube angle
3. Bottom bracket drop (distance from pedal axle to crank arm)
4. Tire clearance (space between outside edge of tire and inside edge of fork crown)

How To Measure A Road Bike Frame Size: 6 Steps

Step 1: The first step is to use the top tube and headtube as a straight line.

Take a tape measure and reach over the frame from one handlebar to the other, then take that measurement up to where it meets  the top tube.

Step 2: Take the measurement from the handlebars to where it meets with the headtube.

Measure this length and  make sure it is the same as the top tube measurement.

Step 3:  Measure the height of the seat tube.

If you are using a road bike, this measurement should be between 74 and 75 centimeters long. If you are using a mountain bike, this measurement should be between 73 and 74 centimeters.

Step 4: Measure the height of your seat  tube.

This measurement should be between 15 and 17 inches for a road bike, or 13 to 16 inches for a mountain bike.

Step 5: Now, take a tape measure and find the distance between your front axle and your rear axle.

This measurement is the distance between where you want to mount the wheels on a trainer or bike stand, and it should  be between 26 inches and 29 inches.

This measurement should also be written down as the distance from front axle to rear axle, or FRA .

You can also measure the distance from your front axle to the center of your bike frame.

Step 6: Measure the distance between your front axle and the rear axle, or FRA.

The shorter distance is the wheelbase.

Your wheelbase  measurement should be between 24 and 27 inches.

Double this number and add two inches for every inch over 27. 

There are charts, but it’s not necessary if you have the measurements of your bike frame handy. 

How To Measure A Road Bike Frame In Cm

It is important to use a measuring tape and measure all of the points on your bike, but some are more crucial than others.

Length:

The length from the top tube to where it meets with the saddle should be between 97-120 centimeters in women’s bikes and 102-122 centimeters in men’s bikes.

The top tube should be at least 20 centimeters longer than the saddle.

so if it’s shorter than that you’re going to have trouble with your leg muscles and backside getting fatigued too quickly on long rides.

Also make sure there is enough room for a water bottle holder or storage bag when riding the bike.

Height:

The height of the top tube should be between 43-52 centimeters, and you want to make sure that it’s not too low or high on your body because if it is then you may have a hard time reaching pedals or handlebars from different angles.

In general, men will need higher bars than women to compensate for different leg lengths.

Seat-post:

For the seat-post, you want to make sure it’s not too long or short so that your saddle height is comfortable and there’s enough room for a water bottle holder on the bike frame as well.

The correct length of a seat tube should be between 90-115 centimeters in women’ s bikes and between 110-130 centimeters in men’s.

Bars:

The height of the head tube is typically 85mm or 100mm, but it depends on what kind of bike you are looking to buy.

Some have higher bars than others. The length for a man should be around 134cm with a range from 124-156 cm in length. Women should have a head tube length of around 125cm with a range from 115-136 cm in length.

How To Measure Yourself For A Road Bike Frame

You will need a measuring tape, and the length of your inseam.

Step 1 :

1. Stand up straight with good posture.
2. Keep one foot on its heel as you measure from that point to the ground
3. Mark the height where it meets the floor.
4. Repeat this process for your other leg and then take an average between them to determine how tall you are without shoes (this is important).

Step 2 :

1. Measure around your chest at nipple level.
2. Or the point where you would wear a bra if you were female and wore one to ride a bike (again this is important).
3. keeping arms relaxed but slightly bent so that they form a “T” shape.
4. This should be done while wearing or holding any clothing which may have been worn during bike riding.
5. Including jerseys if applicable.
6. Just make sure all measurements are taken across garment seams instead of over them.

Step 3:

1. Measure from inseam at groin level up to nipple height.
2. Repeat for the other side and then take an average between both sets of these numbers.

Note: You can measure down either leg since there’s no real preference whether you measure the left or right side.

Measure circumference at the widest point, typically around the thigh just below hip (not in front of crotch) and then take a measurement from that spot to the most narrow part of thighs.

Measure height without shoes on

1. Standing with your back against the wall, legs straight but not locked for best result.
2. Stand up as tall as possible when taking this last measurement.

Note: Your bike’s geometry is one determining factor in how much clearance you’ll need between your head while sitting versus standing. If you have long arms it may be worth considering sizing down so there is a little more room when standing.

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How To Measure Bicycle Frame Geometry

A bicycle frame geometry chart can be used to determine the height, top tube length and head angle. The charts also take into consideration measurements such as

1. Seat post length
2. Stem size
3. wheelbase
4. Reach

Seat post: this is the vertical distance from the center of the bicycle frame to the top of a seat post

Stem size: this refers to how far forward or backward a stem is placed from the center of the bicycle frame

Wheelbase: this is measured horizontally, and refers to how far apart front and rear wheels are.

Reach: this is measured horizontally, and refers to the distance from the center of a bicycle frame to handlebars.

How To Check Road Bike Frame Size ?

Generally, many online stores ( Amazon Road Bike ) or retail stores offer information about a bike’s frame size on their website.

In some cases you may need to verify that this measurement correlates with your own measurements.

For example, I am looking for an 18 inch bike

However, when reading through reviews they mention there are two sizes offered (18″ & 20″). How do I know which one will be best for me?

If you can’t find specifications listed anywhere then measure your height from head to toe without shoes on and divide by two.

For instance: 72 inches divided by two equals 36 inches = 18- inch bike.

That’s it, there is no need to worry about the frame size anymore as you can determine what will work best for your height!

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

If you are buying an off-the-rack bicycle then first measure yourself and make sure you know how tall or long your inseam is (from crotch to ground) before going into the store so that they may be able to give advice on which models might suit you.

Or ask them if they have any bikes with adjustable frames such as those from Cannondale® Cyclocross, Trek®, Specialized® or Giant’s Defy model lines where both seat and handlebar positions can be adjusted.

How To Measure Stack And Reach?

Measure your bike from the center of the bottom bracket to the top clamp on a straight handlebar and then multiply that number by two.

The stack is how high your bicycle’s head tube sits above its seat, with shorter bikes having lower numbers and taller bikes higher ones.

The reach is measured from what point at which you should be able to comfortably touch – usually this will be when gripping the hoods or right below them – all the way back to where it meets up with axel for both front wheels.

Read More How To Measure Hybrid Bike Frame Size – Chart

Conclusion

Finding the perfect size bike for you is an important step in riding more comfortably and getting longer use out of your purchase.

It’s important to measure the bicycle before buying. Hopefully, these instructions- How To Measure A Road Bike Frame have helped with that process by providing a few tips on what to look for when shopping around. If not, we can help!

Once you have these numbers in hand, visit the manufacturer website for each make/model where they should be available. If this content was helpful, please share it with your friends on social media! 

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