How To Measure Bike Stem: Useful Guide (2021)

Bike stem is one of the essential components of a bike. It affects not only your performance but also your position and comfort when riding.

The bike stem could come in various forms and lengths. Thus, choosing the most suitable stem for your bicycle is not an easy task. To get the best option, you need to know how to measure bike stems.

A bike stem length that matches your riding style, body weight will enhance your riding experience. If you do not know, it is time to read this article. Let’s get started!

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What Is A Bike Stem?

What Is A Bike Stem
What Is A Bike Stem?

A bike stem is a component that connects your bike handlebars to the bike frame. It could have different lengths and sizes on different bike types.

You could install a bike stem by using a steerer tube. With different types of bike stem, you will need a specific method to install it.

There are two most common materials to make a bike stem, including aluminum alloy and carbon fiber. Aluminum bike stems are more affordable than carbon stems.

It would be best to choose heavyweight bike stems since they might offer more complicated control.

For more information about a bicycle stem, let’s watch a helpful video on:

Watch video: What is a Bicycle Stem?

The Roles of Bike Stem

The Roles of Bike Stem
The Roles of Bike Stem

You might think that a small thing like a bike stem could not have any impact on your rides. However, the bike stem plays a more important role than you consider.

Firstly, this component will determine your bike handles. With a too short or too long bike stem, your bike could be hard to control and ride. Meanwhile, a right bike stem is very beneficial in enhancing the performance of the front wheel.

Moreover, the bike stem could affect the riding position of your upper body. Depending on your riding needs and the terrains you ride on, you should choose a proper stem length for your bike.

A long bike stem will help you gain high speed more quickly. It pushes your body weight and the front wheel forward. Thanks to that, your rides will be more stable and confident, especially at high speed.

For female riders, they will need a shorter bike stem compared to male riders. The reason is that women have short torsos. As such, this body proportion will reduce the weight putting on the front wheel.

For more information about a bicycle stem, let’s watch a helpful video on:

Watch video: Ask a Mechanic: How Stem Length Affects Your Ride

Types of Stems

Types of Stems
Types of Stems

Depending on the headset style and bicycle fork, you could choose a suitable type of bike stem. Also, specific handlebar diameter and steerer tube diameter will be compatible with different kinds of bike stems.

There are two most popular types of bike stem on the market, including quill stem and threadless stem. Each class has specific features and functions. Thus, you should consider it seriously before going to one of them.

Quill stem

Quill stem
Quill stem

Quill stem is more standard and popular compared to the threadless stem. This one could be made of aluminum alloy or stainless steel.

You could find quill stem on almost all types of bikes, from mountain bikes to road bikes, from cheap bikes to luxury bikes.

This type of bike stem is compatible with a threaded fork. When you install a quill stem on your bicycle, you have to make sure that your fork steerer tube is shorter than the bike headset.

In general, threaded steerers for quill stems will have two diameters, including 1 inch and 1.125 inches. Among them, 1.125 inches steerers are more common than 1-inch threaded steerers.

Threadless stem

Threadless stem
Threadless stem

Unlike quill stem, threadless stems are designed for threadless steerer tubes, which are more modern and favorited recently. You could see this design in numerous sporty bicycles around the world.

There are three standard diameters for threadless steerer tubes, including 1 inch, 1.125 inches, 1.5 inches. As such, you will have multiple options if you go to this type of bike stems.

Threadless stems will come in lightweight materials like aluminum alloy, carbon fiber. Thus, a typical threadless stem will be a little bit lighter in weight than a quill stem.

In terms of price, threadless stems might be more expensive than quill stems.

Items Needed To Measure Bike Stem

Items Needed To Measure Bike Stem
Items Needed To Measure Bike Stem

Measuring the bike stem is a pretty straightforward process. Thus, you do not need many tools and items to do that.

You need to use a pen and a tape measure in centimeters or millimeters since bike measurements are in metric. Sometimes, paper and calculator are necessary.

How To Measure Bike Stem Length?

Even though measuring the bike stem length is an easy process, you still have to do it step by step. You should follow these steps to measure stem length correctly!

Step 1: Measuring your inseam and upper body length

Measuring your inseam and upper body length
Measuring your inseam and upper body length

As I said above, your height is an essential factor determining the most suitable bike stem length. Thus, the first step you should do to measure the bike stem length is knowing your inseam length and upper body length.

Three situations could happen when you do this step.

The first one is that you have a long inseam and a short upper body. In this case, you will need a long bike stem, especially if you are riding on a mountain bike or a gravel bike.

The second situation that you could see is that you have a short inseam and long upper body. With this body proportion, you should go to a short inseam generally.

The last case is that you have a well-proportioned body, which is also the most common case. In this case, choosing the bike stem length is very easy. It would be best if you considered the recommended bike stem length for specific types of bikes.

Step 2: Measuring the correct reach

Measuring the correct reach
Measuring the correct reach

To measure the reach, you have to use a tape and measure from the head tube’s middle to the bottom bracket. If your bike stem places parallel to the ground, the stem length is the reach.

In case you have a stem rise, the reach measurement is the projection of the stem horizontally.

Generally, the bike stem length does not affect the reach. However, it could relate to the effective reach of your bicycle.

Thus, whether you feel stretched or cramped when riding on your bike, it is high time to change a more suitable bike stem length.

Step 3: Considering the optimum position

Considering the optimum position
Considering the optimum position

A precise bike stem will give your arms a slight bend when you hold the handlebars to avoid arm fatigue. A bike stem that is too long will strain your arms when you ride.

To know your position’s best bike stem length, you should sit on the bike and observe the front hub. If you still see the front hub clearly, the bike stem is too short for your position.

Step 4: Measuring the bike stem length

Measuring the bike stem length
Measuring the bike stem length

The final step that you have to make is measuring the bike stem length. It would help if you kept in mind that this length is measured in millimeters.

You need to use a tape measure and start from the center point of your handler bars to the center point on the headset.

Stem Comparison Between Different Bike Types

Stem Comparison Between Different Bike Types
Stem Comparison Between Different Bike Types

Since different bike types will have different designs and riding purposes, a stem on a road bike and another on a mountain bike will not have the same size and length.

You will need a long size for a road bike stem since it will help you have an excellent pedaling position and be comfortable when riding.

The stem length range in road bikes could be from 80mm to 140mm. However, the most common size stem in road bikes is from 100mm to 140mm.

In terms of mountain bike stem, you will need a shorter bike stem to boost the bike handling on challenging terrains. Moreover, a short bike stem will be more responsive.

Therefore, mountain bikes’ recommended stems will have a length range from 50mm to 60mm.

For cross country bikes, suitable stems are from 80mm to 120mm. Such a long stem will help riders feel more confident and comfortable when riding on rugged terrains.

To help you have a quick overview and comparison of stems on different bike types, I have made the following table. Check it now!

Bike types Recommended stem length
Road bikes From 80mm to 140mm
Mountain bikes From 50mm to 60mm
Cross country bikes From 80mm to 120mm
Trail/Enduro bikes From 50mm to 70mm
Downhill bikes From 40mm to 50mm

For more information about a Stem Length, let’s watch a helpful video on:

Watch video: Choosing the Best Stem Length for Your Bike - BikeFitTuesdays

Other Needed Considerations

Other Needed Considerations
Other Needed Considerations

Along with bike stem length, there are many other things that you should measure before going to a bike stem.

Stem angle

In general, stem angle will help you adjust your position when riding. There are two types of stem angles, including positive angles and negative angles. The most common range of stem angle is from negative 10 degrees to positive 17 degrees.

If you feel that your bicycle is relatively low for your height, you could use a positive stem angle to have an upright position and vice versa.

Riders prefer an aggressive position to gain high speed when riding could drop the stem to a negative angle.

Frame size

Frame size
Frame size

Another factor that you should consider before picking a bicycle stem is the frame size. In general, a large frame size will be compatible with a long bike stem, while a small frame size needs a short bike stem.

A typical road bike or hybrid bike will have a large frame size. Moreover, road bikes usually come with a comfy design. Therefore, a long bike stem will make your bike fit your body better.

Handlebar clamp diameter

There are two most common diameters of handlebar clamps, including 31.8mm and 35mm. So the question is, what is more suitable for you?

Generally, if you prefer the strength and durability, I will highly recommend the 35mm handlebar clamp.

However, stiffness is not the best option sometimes. The 35mm handlebar clamp will be heavier in weight than the 31.8mm one. Thus, if speed is your priority, you should go to a 31.8mm handlebar clamp instead.

Clamp design

Clamp design
Clamp design

You could choose a two-bolt clamp or four-bolt clamp design for your bike stem. In general, the function of these clamps is almost the same. However, the four-bolt design is a little bit more stable and durable.

For the front clamp on your bike stem, you might have one option in design that is four bolts clamp. You could choose from a four-bolt design, two-bolt design, or even one bolt design in terms of the rear clamp.

FAQs

Are bicycle stems universal?

Yes, they are. In general, the connection place between stem and handlebars has a standard width. Thus, almost all bike stems on the market could be compatible with your bike.

In short, how is a bicycle stem measured?

You could measure from the middle of the bike handlebars to the middle position of your bike headset stem to know the correct length of your bike stem. This is the simplest method that you could use to measure a bike stem.

What is the stem length of road bikes?

A typical road bike will have a stem length from 100mm to 110mm, which is the most common length in a road bike stem. However, the stem length of road bikes could be shorter or longer depending on the rider’s height.

Is 130mm stem too long?

The answer depends on the rider’s height and the type of bicycle. For example, if you are short and ride on a road bike, this stem length range is ideal for you. However, the 130mm stem is relatively longer for mountain bikes and tall riders.

Is there any connection between the bike frame and bike stem?

Yes, it is. The stem will connect your handlebars to your bike frame. Thus, there must be a connection between the bike frame and bike stem. Depending on the type of stems, you could change this connection.