Below, in alphabetical order, you will find simple definitions of technical cycling terms.
B >
Bar: this is a unit of pressure generally used for tyres. In English-speaking countries, PSI is the unit most often used. Michelin provides you with tyre pressure tables for your bike in Bars and PSI.
C >
CO2 cartridge: very useful in case of emergency, this small cartridge, about the size of a thumb, is most often used as a substitute for a pump to inflate your bicycle tyres. It usually requires a specific adaptor to plug onto the valve and release the air.
Compressor: a compressor (or air compressor) is an inflation device often available from petrol stations. Mainly intended for cars, it can also be used to adjust the pressure of a bicycle if its tyres are Schrader valve-equipped and the compressor has specific settings for cyclists.
E >
E-25 / E-50 bikes: E-25 bicycles are electric engine assisted bicycle, with assistance until 25km/h. E-50 bicycles are are electric engine assisted bicycle, with assistance until 50km/h.
ETRTO : European Tyre and Rim Technical Organization. This is the organisation responsible for defining tyre standards at European level.
F >
Flexible bead (FB) - or Foldable Bead: Invented and perfected by MICHELIN, they are made of aramide (e.g. Kevlar®). They are lighter and allow the tyre to be folded.
G >
Gum Wall (GW) sidewall is coated with a layer of rubber to give it stiffness and protect it. Advantage : resistance to sidewall tears.
Gum-x: MICHELIN GUM-X Compound is designed to optimize grip and rolling speed. It’s adapted to each category in which you will find it in MICHELIN ranges.