The suiveurs and cycling appasionati often draw up conclusions on riders with judgements such as: “Yes, he’s a nice rider, but he has a small engine…”, meaning that the cyclist does not have enough endurance skills, gives in over long distance or to the fatigue accumulating day after day.  

I believe we should rather say that the athlete has a “small fuel tank” or a not so efficient one. 
In fact it is how the tank is working that determines endurance and recovery skills. 
With tank, we mean not only the amount of glycogen or triglicerids that are stored in the muscles, but also the capacity to utilize subcutaneous fatty acids under effort, to feed and assimilate in racing or training conditions. 

With engine instead, we mean the level of performances that the athlete is able to express, notwithstanding fuel availability: great engines are best defined by relatively short efforts, that allow the production of high power outputs, apart from fuel consumption. 

Modern cycling, especially in the last 10-15 years, has been giving more and more prominence to big engines, somewhat lessening the importance of an efficient tank. 
The average level of the riders has been rising remarkably, just as the number of athletes and teams able to actually win at any given race: this brought about some very tactical racing habits, where nobody dares or has the strength to attack early in the courses because too many riders behind would set up an effective chase. 

As a matter of fact, the best riders prefer to wait the final clicks of the final climb before striking an attack: 10-20 minutes all-out, where power is more relevant than endurance, the engine more decisive than the tank. 
Add to this the tendency to shorten the mileage of races and stages, in order to provide a “good show” and supposedly counteract doping practices.. 

The reality of it, at least for the second point, is actually the exact contrary: if it is relatively easy to “tweak” the engine, it is much more difficult to improve and widen the tank. 

The course of the stage with Colle delle Finestre in the last Giro d’ Italia has finally stressed and recalled the crucial importance of endurance, of a smart distribution of the effort, of nutrition and hydration in the race, providing the spectators with an exciting show, riveting and uncertain in the final result. 

Long and hard climbs, or ascents/descents without any long flat distance are the kind of elements that do encourage attacks far from the finish and give priority back to the tank in determining race results. 

Also longer and harder time-trials, with climbs, descents and flats would better fit those less powerful yet more enduring riders. 
In fact there is a big difference between a solitary effort of 2 hours and one that last 40-60 minutes, as marathon runners know so well.