How To.

Tyre Technology - Fitting.

When fitting a tyre and an inner tube, it is important to choose the right combinations of the four components that play a role in the fitting:

   - The rim.
   - The rim tape.
   - The inner tube.
   - The tyre.

The E.T.R.T.O. (The European Tyre and Rim Technical Organisation) has formulated guidelines to combine these components optimally.


The rim

Depending on the tyre width and the tyre pressure, a recommendation can be made about the rim type, rim width and type of rim tape. Note: Most tyres are tighter on SUN Rims.
Hook Beaded rims are to be used for a tyre pressure from 5 BAR (75psi) upward. Carbon rims are usually not designed for pressures above 150 psi. Consult your rim manufacturer with regard to the maximum tyre pressure the rim will take. Remember, worn or old rims will not take the same tyre pressure as new rims.

Below are examples of pressure ratings for some tyres.

 700 x 23C Tyres                                Recomended Pressure       Maximun Pressure

Vredestein Fortezza                                   8.0Bar                               12.0Bar

Vredestein Volante                                     7.0Bar                               11.0Bar

Vredestein Ricorso                                     6.5bar                                9.0Bar

The rim tape

For a tyre pressure from 5 BAR upwards, it is advisable to use a stiff, preferably self-adhesive rim tape, which covers the spoke apertures. The rim tape must touch the inside of both rim walls.

Latex inner tubes

During fitting, the size and type of inner tube used influences the final result. A latex inner tube requires special treatment. A 100% natural rubber latex inner tube has a high elastic deformation of about 900%.This means that the tyre can be stretched up to 9 times its normal size without damage. This will cause permanent deformation. In practice, this means that pumping it up before it is fitted can completely destroy the tube.
Gently inflate the latex inner tube by mouth only before fitting it, so that it adopts its round shape.

Butyl inner tubes

Standard inner tubes are usually made of butyl, a synthetic rubber with low gas permeability.
We make a distinction between two types:

   - Freely vulcanised.
   - Vulcanised in a mould.

A freely vulcanised inner tube is easy to fit. Since a thin layer of talcum powder is present on this tube, it nestles more snugly inside the tyre than the version that is vulcanized in a mould.
Inner tubes vulcanised in a mould have a ridge, which makes them more difficult to repair.     

FITTING INSTRUCTIONS FOR TYRES AND INNER TUBES

Check the inside of the rim for formation of rust, which increases the chance of punctures.

Check the correct position of the rim tape.

Put the tyre with one edge inside the rim.

A coating of Talc inside the tyre will significiently ease the fitting of the tyre and reduce the risk of tube twisting.Insert the valve into the rim and gently inflate the tube.

Press the inner tube over the whole circumference of the inside of the tyre. Press the loose edge of the tyre over the rim at the valve.

Push the valve about 2 centimetres into the rim, push the loose edge of the tyre into the rim, and pull the valve as far as possible out of the rim again.

Take the wheel in both hands, with the loose side turned towards you, and with your thumbs, both to the left and right of the valve, press the loose edge of the tyre into the rim, while holding the other side of the rim with your fingers. Once you have reached half-way, turn the wheel around and push in the part of the tyre opposite the valve.

For the last 15 to 20 cm, let the air out of the tube and insert the remaining section of tyre.Push the valve back as far as possible, and then pull it back out of the rim and fit the rim nut.Inflate the tyre to the desired pressure.