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How is the length of a stem measured? Where does the measurement start and finish?

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up vote 12 down vote accepted

It sounds as though you are talking about what Sheldon Brown term "reach", which is

normally measured center-to-center along the direction of the extension

So this does not take into account the angle of the stem, which could reduce the length forward that the handlebars extend by a small amount if they are on a large angle up or down.

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5 - Edit this into your post. – Vache Oct 21 '10 at 13:34 I've used this to estimate how much rise one would achieve as well. – tplunket Oct 21 '10 at 18:14
@domsterr - thanks for the link - I did see that one but I was looking for something a little bit more specific to just how you take the measurement without the extra info. I added it anyways until I can find or make another. – Anthony K Oct 22 '10 at 1:10
@AnthonyK 1. You answered "reach" but later on you described "extension" 2. The answer should be "extension". A "110mm stem" is a stem with 110mm extension, not 110mm reach – vucalur May 18 at 16:09

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