So, what does this all mean for frame design?
Over the past decades, frames have been designed with shorter and shorter headtubes to please the pros seeking an advantage through a lower handlebar position. Those same geometries are then offered to the masses. As you’ve seen in part 1 and part 2, the only problem with this approach is that it’s wrong. It doesn’t work for the pros, let alone for the masses.
So we need to get these headtubes longer again, and thankfully there is a way to do this without creating a problem for those riders who like their low position (out of habit or because they have the flexibility to take advantage of such a low position).
You see this in the new Cervelo geometry for example. The R3, R5, R5ca and S5 are obviously race-ready, as they are used successfully by the men and women of Garmin-Cervelo. Yet the headtubes are taller than they used to be. Here’s how it works:
The new geometry from the Cervelo R3 and S5 series has a taller headtube so that people can put their handlebars on the correct height without needing too many spacers. At the same time the bars can still be placed low enough to fit any pro rider we have ever supported. The advantage of a longer headtube is that it increases the torsional stiffness of the frame, which in turn improves handling.
On aero frames, it also improves the aerodynamics because despite the headtube being wider than the bunch of spacers sitting atop of it if it were shorter, the shape of the headtube is much, much better and more than compensates for the increased frontal area.
So how do riders still attain the low position with the taller headtube? If you mount a -17 degree stem (that’s a flat stem, so a stem that sits on the bike horizontally) on the new geometry, the handlebars sit just as low as they would with a -6 degree stem (the standard) on the old geometry. 3T, FSA and several other manufacturers now have such -17 degree stems available.
Of course, that said no pro should ever ride the R3 except for Paris-roubaix (which it was designed for originally). The aero frames are ALWAYS the fastest solution, even in mountainous terrain, so every pro taking their profession seriously and wanting to get to the finish the fastest should ride them at all times (except Roubaix).