Having the right stem on your bike can make all the difference in comfort and handling. Changing this small part is an easy way to tailor your bike to fit you better and meet your specific needs. You can also upgrade your stem to save weight or customize its colour.
Types of Stems
A stem is the component that connects your handlebars to the frame of your bike. A threadless stem clamps around the steerer tube of your bicycle’s fork whereas a quill stem inserts inside the top of the fork steerer tube and is held in place internally. An adjustable stem allows you to easily alter the angle of your bike on the stem itself without having to replace the entire unit. Most new bikes come with threadless stems; however, some hybrids and a lot of older bikes have quill stems.
Stem Dimensions
Once you choose the appropriate type of stem for your bike, it is important to determine which clamp dimensions are compatible with your steerer tube and handlebars.
Steerer Tube Clamp Diameter
Most newer bikes come with a steerer tube diameter of 1 and 1/8 in. Some mountain bikes come with 1.5 in. steerer tube and older bikes usually accommodate a 1 in steerer tube diameter only.
Handlebar Clamp Diameter
In recent years the “oversized” or 31.8mm stem clamp diameter has become the industry standard for both road and mountain handlebars. Older road handlebars commonly have a 26.0mm diameter, whereas older mountain bars usually have a 25.4mm diameter.
Mid length stem with slight drop
Stem Angle
A stem’s angle is measured in degrees along a perpendicular axis against the steerer tube when it is sticking straight up. At 0 degrees the stem is flat perpendicular to the steerer tube. Generally, stems range from negative 10 to positive 17 degrees. If a stem has a positive angle, it is often referred to as having a “rise”.If a stem has a negative angle, it commonly referred to as having a “drop”. The higher the rise, the more upright your body position is. The lower the drop, the more aggressive your bike feels.
Stems can easily be flipped around to achieve the opposite angle depending on the desired affect. A negative 10° drop can be reversed to achieve a positive 10° degree rise. For recreation riders, a slight rise is typically most comfortable. Racers usually prefer to have a stem with a drop to attain a more aggressive body position.
Long stem with large drop
Stem Length
Stem length affects the rider’s reach from the saddle to the handlebars. The longer the stem, the longer the reach. The shorter the stem the shorter the reach. Stem lengths span from 35mm to 130mm.
Generally, if you feel too stretched you might need a shorter stem and if you feel to hunched you probably need a longer stem. Proper stem length is dependent on your style of riding and torso length versus leg length. It is highly recommended to get a professional bike fit to find out what length of stem is best for you.
Short stem with a positive rise
Style of Riding and Stems
What type of bike do you have? Do you ride for fun or performance?
Road cyclists have very different priorities to mountain bikers. Likewise competitive racers have different preferences to those who ride recreationally.
Road
Recreational road riders often favour longer stems with a positive rise. A more upright position eases tension on the hamstrings and lower back. For less flexible riders, a stem with a positive rise could relieve some pressure. Longer stems allow you to shift your weight forward more easily, which is helpful on steep inclines.
In contrast, a short stem is usually the best option for competitive road riders. Handling is more compliant and the rider sits in a more aggressive and aerodynamic position. A short stem requires more precise movements, which can feel twitchy to inexperienced riders.
Hybrid
As with recreational road riding, a longer stem with a positive rise is suggested for hybrid riders. However, if a stem is too long it can negatively affect the bike’s handling. Larger frames usually come with longer stems to accommodate taller riders. Conversely, shorter stems frequently accompany smaller frame sizes in order to fit shorter riders. In general, you can easily change your current stem length by 10mm to 20mm without any adverse affects on handling. The ideal stem length for hybrid riders depends on the fit of the bike, which is unique to every individual.
Mountain
Downhill and enduro riders benefit immensely from short stems as handling and maneuverability improves dramatically when descending. With a shorter stem your handling is more responsive; you are able to corner better, lift the front-end more easily, move the bike side-to-side quicker and maintain a more solid position on your bike. Ordinarily downhill and enduro oriented stems have a flat, 0° angle or a very slight rise.
Cross-country and leisure oriented mountain bikers are more concerned with fit than handling when it comes to stem length. Competitive cross-country racers generally have stems with a negative angle or drop whereas recreational riders commonly have stems with a slight rise.
Comfort and Cruisers
An adjustable stem is worthwhile if you want to be as upright and comfortable as possible. However, the adjustability comes with added weight, and an extreme upright position is appropriate for short distances only. For those riding thirty minutes or more, a slightly bent body position is advantageous for muscle function and wind resistance.
Cost of Stems
Most brands offer a myriad of stem options ranging in dimension, style, and price.
A stem costs anywhere between $30.00 CAD to over $300.00. CAD. On average, leisure oriented stems cost around $60.00 CAD, performance stems cost about $80.00 to $90.00 CAD and race stems cost upwards of 100.00$ CAD.
The major determinants for stem cost are weight, stiffness and type of material used. Mountain bike stems are normally more robust and less concerned about weight than road stems. Stems are composed of steel, aluminum, carbon fiber or titanium. Aluminum is the most widely used material. Steel stems are cheaper but heavier, while carbon and titanium stems are lighter but more expensive. Along with saving weight, carbon fiber also helps to dampen road vibrations.
Newer bikes most likely require stems with a 1 and 1/8 in. steerer tube clamp and an oversized 31.8mm handlebar clamp. On average, it is best for casual riders to have a longer stem (70mm to 120mm) with a positive (6 to 10 degree) rise. It is worthwhile to discuss stem options and fit with qualified staff at your local bike shop.
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Learn how to change your stem in our video: How to Change a Stem
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