How to Measure Inseam for Bike in 6 Simple Steps

How to Measure Inseam for Bike? (Size Chart Included)

In general, knowing how to determine the inseam of the bike is essential to get the right bike for you. This is especially important when purchasing bikes for kids or BMX. That’s why this easy guide can help.

To determine the length of your inseam, you must sit straight, with your back against the wall, with your shoes removed. After that, put a hardcover book on the crotch, and measure the floor-to-book (crotch) length.

You can repeat the procedure 3 times and get an average figure, which is the most precise inseam height.

Be aware that choosing the correct size bike means more comfort as well as better performance and the prevention of injuries. Additionally, your height isn’t enough to get an exact bike frame. This is the reason the inseam’s height can be helpful.

This guide will assist you in learning the best ways to measure the length of the inseam to choose the correct bike frame. Before we begin, let’s know the size of the inseam below.

What is the Inseam Length?

Inseam length typically refers to the measurement of your inner leg. It’s the distance between your floor and the crotch region. If you do it correctly, you will have an ideal bike fit which means comfort and a pleasant cycling experience.

How to Find the Inseam for Bike

Before we begin to take a look at the steps, here are some of the things you’ll need:

Requirements

Tape measures
Marker (it could be a masking tape, pencil, or even a pen)
The Hardcover Book (one with a stiff spine)

The Steps:

Below is how to determine the child’s inseam to ride a bicycle:

Step 1: Find the best location.

Generally speaking, you can get the measurements of your inseam wherever. But you must find the perfect location. The most important thing to consider is finding a place to stand straight. It could be right next to the closed door or on a wall.

Step 3: Take off your shoes

Let me begin by pointing out that you can measure the inseam of a bicycle with or without shoes on. However, since you’re likely to be riding on your bike in riding shoes, you should take measurements of your inseam without shoes or using a pair of socks.

It will result in more precise results, not the situation when shoes are worn.

Step 4 – Stand straight.

Place your feet on a level surface with your body against the wall and your legs about 6 to 8 inches apart.

Step 5: Place the book at the bottom of the crotch

Please get a new hardcover book, place it between your legs, and adjust it until it reaches the crotch. While doing this, make sure that you’re standing straight. Get help from a trusted friend.

6. Measure your inseam

In the last step, you’ll need an instrument with tape and measure the distance between the floor and the top of the book (crotch). Note the length using a pencil, marker masking tape, and pen.

Be sure to do this at least three times. Then, add up the three numbers and calculate their average to get more precise results. In the end, you have to get your kid to work with you to achieve greater accuracy.

How to Determine Your Bike’s Frame Size Using Inseam?

Now that you have figured out the length of your inseam, you can determine the frame size based on the bike you’d like to purchase, as illustrated in the following table:

Bike Type	Frame Size
Road bike	Inseam x 0.70
Mountain bike	Inseam x 0.66
Trekking bike	Inseam x 0.64
Hybrid/Cruiser/City bike	Inseam x 0.665

If you’re looking to buy a hybrid bike frame, and your height is 80cm, your ideal frame is:

80cmx 0.665 = 53 centimeters

This means that the hybrid bike that has a 53cm frame will be perfect for you. You can apply the same model to any other bike you want.

For a more detailed frame size based on your inseam, we’ll look at the bikes’ different sizes by the height and length below. Additionally, take a look at my recent piece on the size of the bike frame chart:

Street Bike Frame Size as per Inseam and Height

Here’s a table that matches your rider’s height and inseams with the appropriate road bicycle frame.

Frame Size Name	Frame Size	The Rider’s Inseam	The Rider’s Height
XX-small	33 – 37cm	60.9 – 73.6cm	4’10” – 5’2”
X-small	38 – 42cm	63.5 – 76.2cm	5’2” – 5’6”
Small	43 – 47cm	66 – 78.7cm	5’6” – 5’10”
Medium	48 – 52cm	68.6 – 81.3cm	5’10” – 6’1”
Large	53 – 57cm	71.1 – 83.8cm	6’1” – 6’4”
X-large	58 – 61cm	73.6 – 86.4cm	6’4” -6’6”

Mountain Bike Frame Dimensions by Inseam and Height

Take a look at this table to match your inseam and the height to the right MTB bicycle frame.

Frame Name	Frame Size	The Rider’s Inseam	the Rider’s height
XX-small	13 – 14”	60.9 – 73.6cm	4’10” – 5’2”
X-small	15 – 16”	63.5 – 76.2cm	5’2” – 5’6”
Small	17 – 18”	66 – 78.7cm	5’6” – 5’10”
Medium	19 – 20”	68.6 – 81.3cm	5’10” – 6’1”
Large	21 – 22”	71.1 – 83.8cm	6’1” – 6’4”
X-large	23 – 24”	73.6 – 86.4cm	6’4” – 6’6”

Frame Size for a Commuter/Hybrid/City Bicycle by inseam and height

The method for determining the commuter, hybrid (or city bike) frame of the rider’s length and inseam is similar to the one used for MTBs. Therefore, think of it in the following manner:

Frame Name	Frame Size	The Rider’s Inseam	The Rider’s Height
XX-small	33 – 37cm	60.9 – 73.6cm	4’10” – 5’2”
X-small	38 – 42cm	63.5 – 76.2cm	5’2” – 5’6”
Small	43 – 47cm	66 – 78.7cm	5’6” – 5’10”
Medium	48 – 52cm	68.6 – 81.3cm	5’10” – 6’1”
Large	53 – 57cm	71.1 – 83.8cm	6’1” – 6’4”
X-large	58 – 61cm	73.6 – 86.4cm	6’4” – 6’6”

How do you measure the size of a bike for a Kid?

Children’s bikes aren’t designed to be as large as adult bikes. In this instance, it is necessary to determine the length of your child’s inseam and then match it to the wheel size, as illustrated below.

The Wheel Size	The length of the seam (in millimeters, cms)
10-inch	85 – 90cm (12 – 14”)
12-inch	35 – 42cm (14 – 17”)
14-inch	40 – 50cm (16 – 20”)
16-inch	45 – 55cm (18 -22”)
18-inch	50 – 60cm (20 – 24”)
20-inch	55 – 63cm (22 – 25”)
24-inch	60 – 72cm (24 – 28”)
26-inch	72cm + (28”+)

Closing Notes

Here’s how to determine the inseam measurement for your bicycle. As we said, determining your inseam can be done easily. You must stand straight in front of an open door or wall, move your legs between 6-8 inches, place a book on your crotch, and measure the distance between the floor and your crotch.

If you know the length of your inseam, you can place an order for the bike and be sure it will be perfectly fitted.