The rim tape protects the tube from mechanical damage by spoke ends, metal burrs and holes in the rim.
An appropriate rim tape must completely and securely cover all spoke holes. Hollow section rims require the use of special rim tapes such as Schwalbe High Pressure or Schwalbe High Pressure fabric rim tape. Rubber rim tapes are not suitable for hollow section rims, because the inflated tube pushes them into the holes.
The rim tape must cover the entire rim base. If the rim tape is narrower than the rim base it can slide and expose the spoke holes.
Alternatively, an adhesive, fabric or tubeless rim tape can be used on all rims. Slipping cannot occur due to the heat resistant glue. The 18 mm wide tape should definitely be used for racing bicycle rims (13C, 14C). The 15 mm tape is recommended only for rims with a relatively wide drop-center which offers a contact area next to the spoke holes which is wide enough for the tape.
Some rims have a drop-center with a width of approx. 12 mm. It is intentional on our part not to provide a rim tape of 12 mm or less. Such a narrow tape would provide a very narrow and insecure cover.
Instead, we recommend using a wide tape that reaches from rim wall to rim wall. This may complicate the fitting process, but it provides the best option for a secure covering of all rim holes.