The importance of the Head-Tube Length
by Pro-Tour bio-mechanic Giuseppe Giannecchini
In the recent years we have seen a tendency in some bike manufacturers to produce bikes with increasingly high head tubes. Why? it’s to give higher handlebars, both on the hoods and on the drops hands positions, but is this position more comfortable? I often hear: "A higher front end is more comfortable and after all I am not a racer". It’s the most common perception, amongst cyclists, of a 'comfortable' ride.
Well, that thinking is wrong and here I’d like to explain why.
A position with a higher upper body, or rather, less reclined forward, may be a good solution in some cases, such as for riders who are overweight, have serious spine issues (lumbar and / or neck), hip replacements or reduced mobility. For everyone else it’s important to respect very precise ergonomic angles and ratios. There are some calculations that are universally recognised by scientists, researchers and bio-mechanics.
Often I hear: "it is the fashion of these times to have a tall front end"! but let's be serious: fashion is for catwalks. The fact is that the height of the head-tube is a classic calculation that must remain independent from the temporary tendencies, it must fit perfectly to the body’s morphology, to its needs and individual necessities.
These days there are common beliefs, such as "slammed stem" or "relaxed geometry with taller head-tube VS aggressive geometry" (some manufacturers even offer the same frame size in different options: ‘relaxed’ or ‘racing’). But there’s no such thing as a “slammed stem”, the choice is only to have the wrong height stem or the right height stem setup for your body. Too high or too low can be equally wrong and equally dangerous. There are no such things as "comfortable / relaxed position" and "aggressive, racing and therefore uncomfortable position" because remember: comfort AND performance go together hand in hand and coincide in the exact SAME position, within the narrow limits of a bio-mechanic window of course.
It may seem strange, but a taller front end also means shorter saddle-bars distance, which in most cases aggravates the pressure and overloads the neck / shoulders area, the arms, hands and even the lumbar region. Bio-mechanically, that’s a disaster!
Typical signals of stem height errors are: tingling or numb hands (paresthesia), neck tension and the overall riding position being affected because not having enough space for the spine to extend and relax, the rider finds himself unconsciously shifting his pelvis backwards, sliding far too back on the saddle, affecting the correct saddle height and set-back and therefore the pedalling action. Everything falls out of place as a chain reaction.
I am sure that the many clients who attended our bike fitting sessions can second this point of view of mine, having experienced a massively improved comfort and performance after I had to lower their front end (in many cases) and these results speak for themselves.
