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. If you are an experienced racer, most likely you have been through a bike fit process and know the length of the stem you need.

Stem length has a big impact on the overall fit and ride of your bike. David Caudery / Immediate Media Stems are labeled in two different ways: either (1) the actual angle, or (2) in terms of their difference from 90 degrees. I guess, the numbers are based on mounting the stem on a perpendicular tube, but they have nothing to do with head tube angle on your bike.would rise or drop 8 degrees if the steer tube were perpendicular. This would rise a little more than the 84/6 if in the "flipped up" position, and would be a little lower in the flipped down position.

In other words, for example, the following stem specs that you might see are equivalent, from lowest to highest rise (and drop):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 NB: some manufacturers quote the other way ie 83° which in reality is a 7° rise so don’t expect a near vertical stem! 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. However, you can still find quill stems on some retro-style fixies and singlespeed bikes, as well as some boutique custom builds or cheaper town bikes. Bike stem standards When we talk about stem standards here, we’re primarily talking about compatibility with the streerer tube on your bike (measured in inches), but also the handlebar clamp (measured in millimetres).