These are the conventional that we have historically seen on road bikes. The Drop bar is frequently made of a single piece of aluminum alloy tubing with either a bulged center for the stem to grip or there is tradition of using a separate "sleeve" as a tubular shim to increase the diameter to that needed by the stem. The "Drop" is the descending circular grip at each end of the bar. The Drop style has two commonly referred to measurements. The first is the "width", this the distance on center between the circular descents or "drops" at each end of the handlebar, this is measured in centimeters, (1cm = 10mm). The second question frequently tries to reference whether the bar has a "steep" or "shallow" drop. Steep or shallow are relative terms. We will measure the drop from the center of the "top" (the area parallel with the riders shoulders) of the handlebar to the center of the straight uncurved portion of the lower drop. We did not measure the "reach" of the Drop bars, which is traditionally measured from the center of the top tubing section to the center of the downward curve at its front most. The reason we haven't included this measurement is that it varies when the bar is installed on the bike, based on how the bar is rotated, up or down, before tightening.
