Does the current UCI limit for bicycle weight make sense?

Road 28/04/24 14:17 Migue A.

With the the arrival ofl lighter bikes, the limit of 6.8 kg that the UCI sets for competition bikes is back on the table and to recover the debate that we already lived years ago whether it is an appropriate limit or technology allows to make lighter bikes without these ceasing to be reliable.

Will we see weighted bikes in the World Tour again?

Let's go back about a decade. Before aerodynamics, disc brakes or internal wiring took over almost all bike designs on the market. A time when knowledge of the capabilities of carbon fiber began to take off definitively and manufacturers began to use this material to its full capacity and not, as had been done until then, simply transfer the systems and manufacturing structures that were applied in aluminum and steel frames to carbon tubes.

From there, the bikes underwent an evolution leap and allowed them to be fine-tuned to the limit, a limit that the UCI was responsible for setting, for competition bikes at 6.8 kg determining, according to their studies, that with the technology of that time that was the minimum figure that a bike should weigh to be completely reliable and manageable.

A time when cyclists began to carry lighter bikes we even saw much lighter weight crazy setups. Even brands launched series bikes that lowered that figure and that, to be used in competition had to be weighted and thus reach the minimum weight. Who does not remember that "Legalize my Cannondale" campaign with Saeco cyclists dressed in a prisoner's jersey in reference to the illegal weight of the Six13 model, made with a main carbon triangle and aluminum rear?

The emergence of aerodynamic bikes began to make it more difficult for competition machines to approach the UCI limit of 6.8 kg as there was more material to achieve the profiles that reduced resistance. Something that also contributed to the generalization of the use of high-profile wheels. However, what ended up moving competition bikes away from those weights was the arrival of disc brakes and fully internal wiring that have made almost all bikes on the market gain weight.

However, now brands are again focusing on reducing the weight of bikes, without giving up all the aerodynamic gains and technological innovations incorporated in all these years. This is possible thanks to the emergence of better qualities of carbon fibers, the appearance of new resins that achieve greater cohesion and resistance to frames and the evolution of manufacturing processes, with more precise studies thanks to finite element simulation programs with which every gram of material is squeezed by eliminating them from where they are not necessary.

The result is frames with a level of lightness inconceivable just a few years ago, but not only that, also meeting stiffness or absorption parameters in line with the requirements of a competition cyclist.

Is the limit obsolete?

With all these evolutions in bicycle manufacturing technology, the question, already raised at the time, is again whether that figure of 6.8 kg that the UCI marks as the minimum weight for bikes makes any sense. The answer would be yes and no. On the one hand, the existence of a limit curbs brands against the temptation to exceed limits. In the past, when this debate was in full swing, it was not uncommon to test some bikes around 6 kg. If you were a light and small cyclist this was not a problem, but if you were a corpulent cyclist it was common for those bikes to be a technical exercise, sometimes showing themselves to be tremendously unstable and difficult to drive when speed increased.

However, then advanced studies using FEA software were not available nor were differentiated laminates developed for each size. Nowadays, brands give the importance that corresponds to behavior and all bikes have to meet stiffness and absorption requirements for which each size of the bike is a different development with different laminates. That is, no one is going to lighten a bike just for the sake of lightening if that is going to mean a decrease in its qualities.

On the other hand, the UCI, as a control body, now requires that all bikes to be used in competition must be certified by them. For this, manufacturers have to send designs and frames on which tests are carried out and it is verified that they comply with the technical regulations before giving them the go-ahead and being able to display the characteristic sticker that almost all frames on the market seek to display on their seat tube.

Also, brands have test laboratories, even some with scanner and x-ray machines, not only to verify that the frames they build meet the set parameters as a requirement but also to analyze when a break occurs to determine the cause and take corrective actions if necessary.

It is clear that everything can fail and there are still bikes that break however, a catastrophic failure, for example that a fork or a frame breaks suddenly while we are riding is something extremely unlikely.

With all these evolutions and controls, it would be possible to plan that the elimination of the 6.8 kg limit should not mean that manufacturers went crazy with weight, especially due to the culture that performance does not depend only on weight and neither cyclists nor manufacturers are going to penalize force transfer or wind penetration just to gain a few grams. The proof is in the bikes of recent years where professionals have been competing with bikes clearly above 7 kg.



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¿Tiene sentido el actual límite UCI para el peso de las bicicletas?


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