A stiffer frame is a better frame, right?
To answer this question we first have to look at what stiffness actually is. The value in which stiffness is expressed is Nm/° or Newton meter per degree. There is a certain amount of force needed to cause a certain bending of a frame. A higher value in Nm/° means a higher stiffness of the material. The stiffness of frames is measured at the bottom bracket (BB stiffness) and at the head tube (torsional stiffness). Most of the time also the fork is measured, this is called the fork stiffness. So you can’t generally speak about just “The stiffness” of a particular bike. But you can use the several types of stiffness together to compare bikes or frames.
If all the stiffness values are high, most likely the bike will handle well on the road. But whether the bike will be nice to drive or not is a completely different story. This really depends on the rider's taste. Some riders like an agile and sharp turning bike. Others like a more comfortable bike they can ride on for hours.Both preferences are possible to match with the same frame. This is because for most of the driving dynamics of a bike the sum of all the components is important. Meaning the saddle, the handlebar and the wheels plus tyres are of a great influence of the overall characteristics of a bike.
To judge a bike only based on the stiffness of its frame alone is too short-sighted. Especially in German tests they really tend to focus on the stiffness measurements. A bike with an “average stiffness” is said to be unmarketable. But this bike might be excellent for a big group of potential buyers. You can’t judge a car only based on its engine's horse power, right? Just as with a car you have to look at the whole picture to judge a bike.
Of course there are lower limits on which a frame should meet. Especially in the Netherlands, because Dutch people tend to be quite strong compared to other European countries. Sensa frames are built to last and to handle well. This makes it possible to sell a safe and reliable bike. For us it is self-evident that this demands for a certain degree of stiffness. Meaning for us this is so obvious that we not explicitly use these values in our communications like our website or catalogues. As a Sensa driver you are always assured of a frame of which you do not have to worry about stiffness.
After all the above, it is clear that the question with which this story started is not as easy to answer. For one rider a very stiff frame could be perfect but another rider might look for a more moderate stiffness. After choosing the right base you can still customize your real dream bike with adding all the right components for you.
So a stiffer frame isn’t always a better frame?!