Road bike components: Which gear ratio do I need?

Road bike gearing: choosing the right gears

All manufacturers can cover a wide range of requirements with their gearboxes. For road racing bikes, three typical chainring ratios have become established: Strong racing cyclists use the professional 53/39 ratio, while the 52/36 combination is almost as fast at the top end, but more suitable for mountain biking and therefore popular with amateur athletes.

The compact crank with 50/34 is the first choice for long tours and mountains. SRAM AXS chainrings (and sprockets) are all smaller, but offer comparable gear ratios. Occasionally, manufacturers offer even smaller chainrings, especially in cheaper groupsets; they are ideal for tackling even the steepest climbs.

Deciding on the right road bike gear ratio is more difficult on the rear wheel - here it is important to find the right balance between the finest possible gradation and sufficiently light mountain gears. The more sprockets there are, the better this works: For the new twelve-speed groupsets, therefore, only two, maximum three different packages are offered. If in doubt, however, it is better to choose a smaller chainring than a large cassette with a coarse gradation.

Important to know: Not all road bike gear ratios are offered in every groupset; usually the expensive groupsets are designed for racing and extreme mountain gears are not offered; conversely, inexpensive groupsets lack the fast gear ratios.

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There are special groupsets with adapted gear ratios for gravel bikes. With the available combinations, the speed range is shifted downwards; the chainrings are smaller than on road bikes, but the transitions are smooth. Drivetrains with only one chainring are now popular and do not require a front derailleur.

Although this leads to larger jumps between neighbouring gears, most cyclists are not bothered by this when riding off-road, with more frequent and greater speed changes than on the road. On the other hand, operation is extremely simple - there is only "heavier" or "lighter" - and the front derailleur is no longer a potential source of error.