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TECHNICAL GLOSSARY

UNDERSTANDING THE VARIOUS MARKINGS AND OTHER TECHNICAL INFORMATION

MARKING IN MILLIMETRES

Example: 650x32A (32-590)

  • The first number (650) denotes the overall diameter of the tire in millimetres.
  • The second number (32) denotes the tire section in millimetres.
  • The letter A indicates that the rim is a 590 mm.


MARKING IN INCHES

Example: 26*1 3/8 * 1 1/4 (32*590)

  • The first number (26) indicates the overall diameter of the tire in inches.
  • The second number (1 3/8) denotes the tire height in inches and fractions of inches.
  • The third number (1 1/4) gives the tire section in inches and fractions of inches.


Special case of marking in inches:

Example : 28*1 5/8 * 1 1/4 * 1 1/8 or 700 C Course or 32-622

  • The first number (28) denotes the tire's overall diameter in inches.
  • The second number (1 5/8) gives the height of the tire in inches and fractions of inches.
  • The third number (1 1/4) indicates the tire section in inches and fractions of inches.
  • The fourth number (1 1/8) denotes the width of the rim which accommodates this tire in inches and fractions of inches.

 

ETRTO STANDARD MARKING

Example: 32*590 (650*32A)

  • The first number (32) indicates the tire section in millimetres.
  • The second number (590) gives the tire diameter in millimetres.

 

GLOSSARY

  • ETRTO : European Tire and Rim Technical Organization.
  • The Gum Wall (GW) sidewall is coated with a layer of rubber to give it stiffness and protect it.
    Advantage : resistance to sidewall tears.
  • The Skin Wall (SW) sidewall allows us to make out the texture of the casing through its transparency.
    Advantages : lightweight, flexible and efficient.
  • Overlap : Central part of the casing.
  • Weight : The weights stated are given as a guide with a tolerance of plus or minus 7 %.
    This variation is due to the natural elements inherent in the construction of tires.
  • P.S.I.: Pound Per Square Inch or BAR or Kg/cm².
  • Section : Width of the inflated tire from sidewall to sidewall.
  • Shore is a unit of measurement ranging from 0 to 100. This unit measures the hardness of elastic products. (From 0 soft to 100 hard).
  • TPI : Threads Per Inch- number of threads per inch.
    This measurement represents the density of cords in the tire casing. The greater the density, the lighter, more flexible and mobile the tire.
  • Wire bead (WB) : Being made of steel wire, they are cheap.
  • Flexible bead (FB) : Invented and perfected by MICHELIN, they are made of aramide (e.g. Kevlar®). They are lighter and allow the tire to be folded.
  • Tubeless : Tire fitted without inner tube. It needs specific rims. The advantage of the tubeless tire lies in its ease of implementation. As the rim is already fitted with a valve, the tire just needs to be fitted and maintained.
  • Tubeless Ready (TLR) : Tubeless Ready tires can be fitted without an inner tube provided that a tubeless wheel is used, the maximum pressure is not exceeded, sealant is added and the tire pressure is checked before each ride.

Fitting a MICHELIN mountain bike tyre

HOW TO MOUNT AND UNMOUNT A MOUNTAIN BIKE TIRE?

Fitting a MICHELIN road bike tyre

HOW TO MOUNT A ROAD TIRE ?

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