出处 : bikeradar 作者 : Simon of Bromley
If you've been following the professional road circuit lately, you've probably noticed that many riders are using a larger crankset. Generally speaking, the 53T large disk and the 39T small disk constitute the standard configuration in the mainstream car group, that is, the so-called standard disk. At the same time, recreational riders tend to use smaller discs, and professional riders are opting for larger platters instead. For example, platters of 54T or larger have become common on the World Tour these days, as well as in non-time trial events and large group events.
Shimano's flagship Dura-Ace Di2 R9200 kit introduced a 54/40T platter combo in 2021 to replace the original 53/39T configuration, with some riders even swapping the maximum disc for a 60T in some races. With today's pro riders going so fast, do they really need a much larger crankset than they used to be, or does this technological trend have more advantages than what we see on the surface? Let's investigate.
Pro riders may get faster and faster, but that's not the whole reason
Given the varying conditions, tactics and tracks of professional road races, it is difficult to make a uniform judgment about the speed of the World Tour in recent years. However, it is widely accepted that the speed of riding in the professional arena is getting faster and faster.
For example, the average speed of the last three Paris-Roubaix championships has been increasing. There are a number of potential reasons behind this increase in average speed. For example, aerodynamic design has been widely used in equipment, and the difference is striking when comparing the vehicle of this year's Paris-Roubaix winner, Mathieu van der Poel, with that of the 2013 Fabian Cancellara.
Similarly, more and more riders are using power meters in training and competitions to optimize their performance. Significant progress has also been made in reducing rolling resistance and the impact of replenishment on bodily functions. So all of the above combined results in faster speeds on the field, and larger discs are needed to maintain faster speeds.
Doesn't a 10T flywheel make the platter smaller?
Increasing the size of the crankset is one way to achieve a larger gear ratio, but it can also reduce the size of the flywheel. SRAM and Campagnolo, for example, have introduced a 10T cassette to their high-end road bike kits in recent years, but both brands have also reduced their crankset size.
SRAM's latest AXS suite replaces the legacy combination of 53/39, 52/36 and 50/34T with 50/37, 48/35 and 46/33T. Campagnolo's new Super Record wireless kit is available in 50/34, 48/32 and 45/29T options.
With the 10T flywheel, there is a lighter overall system weight and a larger gear range option at the same gear ratio as the 11T. While they have such potential benefits, the sponsor riders of both brands also use larger discs. Why would they rather give up weight superiority?
The larger the platter, the higher the efficiency
In fact, the reason is simple, in short, all other things being equal, larger platters are more efficient than smaller ones. This conclusion is made possible thanks to test data from companies such as Friction Facts, an independent company that previously specialized in drivetrain friction testing and is now owned by CeramicSpeed.
It was found that the 39x11T combination with almost the same gear ratio produced about 1.5W more friction than the 53x15T combination. The reason for this is that larger platters and larger flywheels have less chain tension and can also reduce the amount of hinges required per link. For the same reason, a larger rear derailleur is also theoretically more effective than a smaller rear derailleur. When considering the chainline effects of the actual drivetrain, the impact of using larger platters can be even more significant.
When using a 39x11T gear ratio at a typical 11-speed or 12-speed, chain crossover can be very noticeable, resulting in increased drivetrain friction. With a 53x15T combination, the chain line is usually straighter and therefore more efficient.
So essentially, professional riders are trying to use a combination of larger platters and straighter chains to increase riding efficiency.
Four-time time trial world champion Tony Martin was a pioneer in this regard, often pairing the large crankset of the 58T with a flywheel with a wider gear ratio range throughout his career. And now, more drivers are pushing the boundaries even further. For example, Ineos Grenadier Racing's Tobias Foss used a huge 68T disc in the 2024 Tour of the UAE time trial, while his teammates Josh Tarling and Ben Turner used 60 and 62T discs at this year's Paris-Roubaix race.
They may rarely use the smallest flywheel in these races, but having a straighter chain at high speed and high power output will obviously give such a high-level rider a considerable advantage.
Should amateur riders consider using a larger platter?
It's easy to think that if a professional is doing something, it must be a good thing and something to emulate. But when it comes to disc selection, most amateur riders are better off optimizing gear ratios based on terrain and type of riding.
While larger platters and flywheels may increase efficiency when used alone, they may reduce efficiency when climbing slopes if they are too large. Similarly, if you opt for a platter that is too large, you may use a small platter for a long time to meet the actual riding, which may negate any performance gains or even make your situation worse.
Of course, if you can meet some specific situations, such as riding on flat terrain, the pursuit of large platters is of positive significance to improve efficiency.
Generally speaking, if you only have one bike for an all-round ride, the first thing to consider is the suitable, wider range of gear ratios. In terms of drivetrain life, while larger discs and cassette gears can reduce friction and theoretically do extend the life of the drivetrain, in everyday use, the best way to reduce wear and tear is to keep it clean and use a better chain oil.
Editor in charge: Ting