Next October 2025 UCI Gran Fondo World Championship Time Trial competitors will be banned from stuffing anything extra inside their aero skinsuits, based on the latest Union Cycliste Internationale (UCI) technical memorandum.

In the past riders used the ‘Bibendum’ hack, named after the bulgy Michelin mascot, to gain an aerodynamic advantage by stuffing non-essential items like towels, bubble wrap or a hydration bladder down the front (or back) of a jersey. The end result artificially helped streamline a rider’s body, which then reduced aerodynamic drag by an estimated 5-9% in time trial events.

Effective 1 February 2025, UCI clothing regulation 1.3.033 has been revised to prohibit adding any non-essential items on or under clothing and other items or accessories worn by a rider to modify their morphology.

1.3.033: Moreover, any non-essential element which is added on (or under) or integrated in any clothing, or other item or accessory worn by a rider shall be forbidden. A non-essential element shall be any element which does not have a purpose which is exclusively of clothing or protection, or which is not strictly necessary for the functionality of the clothing, or other item or accessory. This shall also apply regarding any material or substance applied onto the skin or clothing and which is not itself an item of clothing or another item or accessory worn by a rider.

For the last few years the UCI has prohibited clothing from modifying the morphology of a rider. This latest memorandum adds that non-essential elements also cannot modify a rider’s morphology.

Photo Credit: Getty

© 2019-2025 All Rights Reserved Gran Fondo Daily