Although this is a general outline, the stem length should be decided based on a complete bike fit. This depends on your torso length, arm length and flexibility. Take into account that frame size will play a large role in determining the correct stem length. Handlebar stems look like a fairly standard piece of equipment but have a massive influence on control and comfort. Get the wrong size stem and not only does reaching the bars become an issue but steering as well. 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.

When choosing a stem the main things to consider are length, rise, bar diameter and material. Don’t get too hung up though, it’s a relatively easy decision making process when deciding what’s right for you.The majority of riders will appreciate a fairly low angle ie. less than 10° as this gives a fairly neutral position with just a low rise. Leisure riders will appreciate a more upright position. Racers will try to get a low as possible for better aerodynamics. would rise or drop 6 degrees if the steer tube were perpendicular. This would rise a little more than the 90/0 if in the "flipped up" position, and would be lower in the flipped down position. There’s no hard and fast rule for choosing a stem, it’s mainly whatever works best for you. Two identical riders with identical bikes may need a different stem so just make sure whatever you have works best for your needs.

Racers will want the longest, lowest stem they can get away with and still be in control. This stretched out position will be better for aerodynamics. Some prefer light weight while some will sacrifice low weight for strength and rigidity, especially so for larger riders and sprinters. In other words, for example, the following stem specs that you might see are equivalent, from lowest to highest rise (and drop): Regular riders will want a fairly neutral position so will go with a slight rise, say 6° or 7° and a middling length according to their needs and position.

Bike stems range between negative 10 to positive 17 degrees. When a stem has a positive degree, it is called a “rise”. The stem with a negative degree is commonly referred to as “having a drop”. The higher the stem rise is, the more upright your position will be. Alternately, the lower the drop of the stem is, the more aggressive your bike will feel. Quill stems went out of fashion because the contemporary bolt-on stem and fork design is stronger and lighter. It’s easier to manufacture too, because with a quill stem the steerer tube needs to be threaded, with a screw-on top headset bearing.