Bike Stem Extension Buying Guide

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Bike Stem Extension Buying Guide

Part of the fun of cycling, for many people, is modifying and adjusting the bike. And of course, having the right bike is an important part of getting the most out of one's body. A good bike allows the cyclist to maintain an efficient, comfortable posture and to keep pushing hard hour after hour. Bicycle construction and maintenance is one of those subjects that can easily absorb many hours of a person's time because there is so much detail to learn. Even looking only at one part of the bike, in this case the front-end assembly, there can be almost endless variation in the construction of each separate part.

One alteration many cyclists make, or consider making, is to add a bike stem extension in order to raise the height of the handlebars. While there is not a lot of choice in bike stem extension types, it is still important for a buyer to carefully research whether an extension is really the best option in his or her situation, and to make sure that the extension fits properly into the existing frame. When a stem extension is really the right choice, it is a simple and effective way to get the most from a bike.

The Anatomy of a Bicycle

Any discussion of bicycle parts has a lot of specialised terms than can confuse readers who are not especially fascinated with bicycle maintenance already. While most people are familiar with the shape of bicycles, not everyone knows the names of all the different parts. A detailed look at the front of a bike where a bike stem extension would go should help. All bicycles, regardless of their design, have certain features in common, but they differ in the relative proportions of their components. The frame of the bicycle consists of a series of tubes, including the seat tube, the short head tube, and the fork.

Bicycle Front End and the Bike Stem

The fork is the tube that supports the axil of the front wheel. A vertical extension of the fork is the steerer, which passes through the head tube and headset. There is no way to see the steerer without taking the bike apart. The headset is the piece at the top of the head tube that allows both handlebars above and the fork below to turn.

The stem fits into the top of the headset and attaches to the steerer and then juts forward to support the handlebars themselves. The shape and size of the stem dictates the position of the handlebars relative to the rest of the bike. In many bikes, the stem is adjustable and can be raised and lowered, but if the rider wants to raise the handlebars farther than the stem allows, he or she has only two options: either replace the stem or insert a stem extension in between the headset and the stem.

Why Buy Bike Extensions

When shopping for a bike stem extension, the important considerations are whether a stem extension is really the best choice and whether the extension is the right size and type for the bike. Posture is important for serious cyclists, and different kinds of cycling require different postures. Racing requires the back to be held as close as possible to the horizontal in order to minimise wind resistance. The racing posture is efficient for very intense peddling and it requires the handlebars to be set very low relative to the seat. However, touring cyclists or more casual cyclists need a more upright posture for both comfort and for staying power. Unfortunately, many road bikes are built with racing in mind and their handlebars are positioned too low for use in other contexts.

While bike stems are adjustable, many of them are installed at or near their highest setting. Buying a new stem is one option, and it is also possible to buy a stem that has not been cut to length and have it custom cut. But buying a new stem can change the distance between saddle and the handlebars, essentially changing the fit of the bike. If the existing stem works well, and the peddler does not want the hassle of buying a new fork, a stem extender can be very useful. Some cyclists also use extenders because their bikes are too small for them. An extender can be a good way to try out an effectively larger frame without having to actually buy a new bike. If the trial works out well, then the cyclist can go ahead and get a new bike with confidence. Casual cyclists typically have no need for stem extensions as slight variations in posture do not make much of a difference for their purposes.

How Far to Extend the Bike Stem

Whether to extend the bike stem and how far is something of a personal decision but it is based on the body type and interests of the rider. Mountain bikers often want to adjust their handlebars lower rather than higher, for better control going downhill. Adjusting up is more common for road cyclists who either do not want to use the low racing posture or are riding bikes that are too small for them. People with proportionately very long legs sometimes use stem extensions as well, rather than buying a custom made frame. Road bikes made for racing generally have the seat a few centimetres above the level of the handlebars, while touring cyclists usually prefer the handlebars to be near or at the same level as the seat.

Different Types of Bike Stems

There are two basic ways for the stem to fit into the bicycle's fork. There are threaded stems that fit inside the steerer and threadless stems that simply clamp onto the steerer. There are also multiple types of bolt and clamp systems used to anchor the stem to the steerer. Whether the stem is threaded or threadless dictates how adjustable it is and thus how likely the cyclist is to need a stem extension. There are stem extensions for both threaded and threadless stems, but the extension needs to use the same system that the stem does.

Sizing a Bike Stem Extension

Handlebars and stems come in multiple diameters and have to match each other. The stem, in turn, must match the diameter of the steerer, a piece that is inside the headset and not visible unless the bike is disassembled. When adding an extension, it must also match the diameter of the other components. At one time, there were a huge number of different standards since almost every country and every bicycle company had a different understanding of how big a bicycle handlebar should be. Over time, the number of standards is being condensed so that newer bicycles are designed for one of only a few different sizes, but older bikes that follow discontinued standards still exist.

Stem extenders come in more than one size, although there may be bicycles that do not fit available extenders. Threaded systems can cause some confusion, because the size is normally expressed in terms of the outside diameter of the steerer. Not only is the steerer not visible, but the stem has to be slightly smaller in order to fit inside the steerer. Sometimes the size might be expressed as the diameter of the stem instead and which measurement is meant may not be clear. In any case, buyers should make sure the extension fits the stem.

Bike Stem Extension Safety

If the stem, steerer, or any of their associated components break, they are likely to break when the cyclist is putting a lot of stress on them. These kinds of equipment failures often cause catastrophic accidents than can cripple or kill cyclists. Forcing components to fit together or otherwise exceeding manufacturer's recommendations is likely to cause the parts to break or disengage.

It is important not to extend a stem or extender too far up or jam it too far down, as the components may not grip each other properly. Using extensions puts more torque on the steerer. Although extensions are generally considered safe, especially if the steerer is carbon fibre, it is wise to speak with a mechanic to be sure that using an extension does not cause undue stress. Finally, depending on how much height is added, it may be necessary to replace the brake and gear cables with longer cables.

How to Buy Bike Stem Extensions on eBay

Shopping on eBay is a good and quick way to find a bike stem extension, especially for those who want to install it themselves. Typing 'bike stem extensions' into the search box located on eBay's home page is a good place to start looking for the bike stem extension that is right for your type of bicycle and suits your budget. Since stem extensions may also be listed as stem extenders, stem raisers, and stem adaptors, searching for these keywords as well may generate relevant results.

To look for a specific type of extension, use filters, such as component type, bicycle type, and specify the condition of the item, either new or used. A simple way to avoid any problems is to read through the listing again before buying. It is not uncommon for people to misread listings and buy the wrong product by mistake. Use the contact link on the seller's profile page to ask any questions and to look up the seller's feedback score and return policy.


Cyclists who think the handlebars on their bicycles are too low, or who get back and neck pain while riding have several options. While adjusting the handlebars higher is possible for some bicycles, for many bicycles this only gains a few centimetres, which may not be sufficient for the cyclist. Buying and installing a new stem or fork might work sometimes, but might also change the distance between the seat and the handlebars, thus changing the balance and fit of the bike. A stem extension, while not the most elegant solution for some cyclists, is still an inexpensive and convenient way to make an otherwise excellent bike work better and improve the cyclist's posture. Before buying a bike stem extensions, buyers should consider the type of bicycle they have and the features of different types of bike extensions, such as their size and safety. eBay has a wide range of bike stem extensions, in both new and used conditions, and cyclists are likely to find the bike extension that is right for their needs and suits their budget.

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