Project presentations on the website

Every project supported by Gebert Rüf Stiftung is made accessible with a web presentation that informs about the core data of the project. With this public presentation, the foundation publishes the funding results achieved and contributes to the communication of science to society.


Self-Inflating Inner Tube


Für den Inhalt der Angaben zeichnet die Projektleitung verantwortlich.


Dieses von der Gebert Rüf Stiftung geförderte Projekt wird von folgenden weiteren Projektpartnern mitgetragen: University of Bern; PumpTire AG

Project data

  • Project no: GRS-063/12 
  • Amount of funding: CHF 100'000 
  • Approved: 24.01.2013 
  • Duration: 02.2013 - 05.2014 
  • Area of activity:  Pilotprojekte, 1998 - 2018

Project management

Project description

The project’s goal is to create an engineering model and rudimentary design for a self-inflating bicycle inner tube. The basis for the design is a patented technology that incorporates a pumping mechanism into the inner tube. As the wheel roles, the pumping mechanism collapses under the weight of the wheel pushing air into the inner tube. Once the load is removed the pumping mechanism returns to its original shape drawing in air for the next cycle. The project focuses on the initial analysis, design and build of an engineering model to understand the fundamentals of the system. From this model an actual prototype will be created and then optimized though iterative design optimizations. A control system will be built to regulate the pressure of the system and finally the design will be analyzed for manufacturability. The results of the project will be transferred to PumpTire AG for commercializing of the technology.

What is special about the project?

The novelty in the project is 1.) that it brings self-inflating technology to bicycles and 2.) the pumping mechanism is constructed as part of the inner tube. Most concepts for self-inflating tires focus on the automotive field and incorporate the mechanism into the tire directly. Unlike automobiles, most bicycle use inner tubes. Incorporating the technology into the inner tube creates significant benefits in pricing, competition and margin.


There were three primary results of the project.
1. We were able to complete the design of the air handling system to that it maintained its integrity at 4 bar.
2. We were able to create 2D finite element models of the pumping mechanism and gain a better understanding of how the system works.
3. We also built 10 separate prototypes combining the learnings of the first two point. However, the prototypes did not pump air.

We believe there are two factors that contributed to this. First the sytem may have benefited from additonal stiffness in the perimeter band. Second, it is believed materials touching the pumping mechanism tended to dissipate the force needed to compress the pumping mechanims.


Eurobike Gold Winnter 2019: AirWinder Self-Inflating Bicycle Tire

L'Agefi «Cyclisme peut-être à un tournant», 18 Avril 2013;
Bilan «50 start-up suisses dans lesquelles investir», 23 Février 2013;
Le Temps «Gonfleur ses Pneus de Velo en Pedalant», 14 Février 2012;
20 Minuten «Der Pneu, der sich selbst aufpumpt», 16 Mars 2012;
NZZ Online «Eine runde Sache», 14 Mars 2012.


Persons involved in the project

Last update to this project presentation  15.10.2019