When gravel wheels riding grows more popular,the bicycle stores are more prefer to stock 35mm width gravel wheels.Over time, the 700x40c specification gradually became the standard.But nowadays, 45mm-50mm wider carbon gravel wheels get more attention which is often exactly what racing drivers need.This trend is not only present in the gravel field, but also in road cycling.And earlier,the mountain bikes have witnessed this evolution.
Why are the wider tires of gravel wheels actually faster?
This phenomenon is particularly evident in the mountain riding - in the competitive events such as the XCO Olympic Cross-Country Race, Marathon cross-country race and short track race, 2.4-inch wide tires have long been common.Road bikes have not been immune to the trend of larger tire sizes either.At the beginning of this century, the standard 700x23c tires were successively replaced by 25mm and 28mm ones. However, after Tadei Pogacha adopted 700x30c tires in the Tour de France last year, this specification is about to become the new normal. Only road cross-country races are subject to the rule cap of 33 millimeters.
Obviously, gravel cycling cannot be excluded from this "tire fattening" movement, especially when laboratory tests have verified the conclusions that have long been confirmed in other fields: wider tires can reduce rolling resistance, and the effect is particularly significant on rough roads.
The key principles of efficiency
The core mechanism for improving the efficiency of wider tires in all fields is the same: by reducing the bouncing and brief off-ground phenomena caused by uneven road surfaces, and avoiding the loss of pedaling force in these microsecond-level moments.
Laboratory tests with different wheel diameters have proved that small-sized tires only have an advantage on absolutely flat roads. In fact, even the 29x2.2-inch mountain bike tire has less rolling resistance than the common gravel tire specification - the resistance difference between the current 35mm tire designed specifically for all-terrain and the mountain bike tire can be as high as 42 watts.
The game of weight and resistance
The traditional views hold that the drawback of wide tires lies in the increase in weight. However, the power increment required to drive the additional weight is much smaller than the rolling resistance loss saved due to the increase in tire volume. Moreover, the wide tire's body structure, which does not require excessive reinforcement, can instead achieve greater lightweight and high flexibility, further optimizing the rolling performance.
The advantages beyond power data
In typical gravel races that often involve extremely long distances, wide tires also have another key advantage: by supporting lower tire pressure without sacrificing rolling efficiency, they significantly enhance riding comfort.
These advantages have been widely approved by gravel racing players. At the first Gravel World Championship where all top cyclists chose road bikes equipped with off-road tires may become history. In fact, the 700x45c to 700x50c specifications have become the norm in races. If the technical difficulty of the track is high, some riders will even directly choose XCO mountain bike tires.
The only unknown is where the end of this "tire fattening race" lies? Perhaps technology is a cycle. If this continues, gravel bikes may lose their multi-functional nature and eventually follow the development path of mountain bikes.
