Clincher road bike tyres
English term for classic folding or clincher tyres with an inserted inner tube. These road bike tyres can also be ridden on rims designed for tubeless tyres, but must always be fitted with a tube. Without an inner tube, they hardly seal at all and can come off while riding.
Tubeless road bike tyres
Folding tyres that can be ridden without a tube. You need special rims and, if necessary, airtight rim tape; the valve is screwed directly into the rim. A milky, coagulable liquid seals the system and also repairs small punctures. Further advantages of the system are increased safety against punctures (the inner tube can no longer be pinched) and usually a slightly lower rolling resistance. Because they can be ridden with less pressure, the comfort potential of these road bike tyres is greater. They can also be ridden with the inner tube inserted (e.g. in the event of a puncture), but are then often very difficult to fit.
Tubeless-Ready/TLR
Designation for rims or tyres that can be ridden both tubeless and with a tube inserted. However, tubeless-ready tyres should preferably be ridden without a tube, as they are designed accordingly.
Hookless rims
Rims whose sidewalls no longer have hooks on the inside to hold the tyre - i.e. have "smooth" sidewalls. Such rims are lighter and can be produced more easily, but also pose a safety risk: the tyre can come off more easily. A lower maximum pressure is therefore prescribed for such rims, usually less than 5 bar. In addition, only certain approved road bike tyres may be ridden on these rims. As a rule, these are tubeless tyres, only occasionally clinchers. It is therefore essential to observe the tyre approvals of the rim manufacturer!
Tyre clearance
Specifies the maximum width that road bike tyres can have to fit through the frame and/or fork. Rim brakes usually set the limit at 28 millimetres. For disc racers, the bike manufacturer specifies a maximum permissible tyre width, although this is often provided with a generous safety margin: in most cases, two millimetres more is easily possible.
Jaw width
Refers to the inner width of the rim between the rim flanges. With rim brakes, 15 millimetres was standard, with disc wheels for racing bikes there are now rims up to 25 millimetres - and even wider for gravel bikes. It makes sense to at least roughly match tyre width and rim width: On a very narrow rim, a wide road bike tyre forms a real bubble when viewed in cross-section, while the sidewalls on the wide rim bulge less and are steeper. This has an effect on handling, especially tracking stability: on a narrow rim, the tyre bounces slightly better, but turns more slowly and feels doughy in fast bends; on a wide rim, it is more stable, rides more directly and is more agile. Conversely, a (too) narrow tyre on a wide rim feels wobbly. As a rule of thumb, the tyre width should be around 10 to 20 percent greater than the rim width.
Width for road bike tyres
Nominal width of a tyre in millimetres; how wide a mounted tyre actually is depends heavily on the rim width (or inner width) and tyre pressure. A tyre curves wider on a wide rim than on a narrow one (see rim width). Important: The dimensions of new tyres are designed for modern road bikes with rims up to 21 millimetres wide; on bikes with older, narrower rims (15 to 17 millimetres wide) they are up to three millimetres narrower. A 28 mm tyre may then only be 25 millimetres wide. Conversely, an old 25 mm tyre will be wider on a new rim.
Jens Klötzer
Editor
