Originally Posted by seeker333

Equally important, raising the bar shortens reach.

1---> Raising the handlebar literally shortens reach (the horizontal distance from saddle to handlebar). For every 3cm of bar height increase, you shorten reach ~1cm. Mathematically this is expressed simply as: reach reduction = cosine (head tube angle) x height increase. If you raise the bar on a 54cm LHT (HTA=71d) by adding three 10mm headset spacers, you will shorten the reach by exactly 9.767mm.

2---> Stand with arms hanging straight down, then raise your arms fully extended, and note the arc your hands form as they move ultimately to a horizontal position. As you raise your arms, the horizontal distance your hands reach increases. This also happens with regards to bar height - as you raise bar, your hand position is raised, and your arms "grow" in reach.

These two factors together mean that as a handlebar is raised, it becomes easier to reach the normal grip location. A frame that may seem too large based only on a glance at the effective top tube (ETT) length may in fact fit perfectly, or even be a bit short when the final handlebar position is considered.

Some believe the ETT length on LHTs to be long for a road type bike. Road bikes are typically designed so that the seat tube length and effective top tube length are equal. Using only ETT length to predict fit works better with road bikes, because the handlebar is typically pretty low. But touring bikes usually are fitted with a higher bar, which shortens reach more than the ETT only would predict. The "long" ETT of a LHT actually makes sense, because by the time you raise the bar you need every bit of the ETT, if not more.