The chainring is an important part of the bicycle transmission system and one of the most important highlights of the entire vehicle. A good crankset can not only make your car pedal more efficiently and feel better, but also make your car more dazzling and dazzling. So how to correctly understand this part?

The entire crankset technology focuses on three aspects: the chainring. Crank, bottom bracket system. Next, I will give you a detailed explanation in the form of pictures and texts.

First of all, let’s take a look at the following three cranksets. These three cranksets can be said to be relatively representative products, namely SHIMANO’s MC20, LX570 and RACEFACE EVOLOCE XC. Let us analyze these cranksets in detail from three aspects. 1 Chainring

First, let’s take a look at the MC20 chainring

The MC20 chainring uses a three-layer rigid sprocket. The rigid sprocket has good wear resistance and It is cheap and suitable for use on travel bikes that require long-distance riding. However, since the steel itself has a certain elasticity, it is easy to deform at the moment of vigorous pedaling, which will make the players feel weak. Moreover, the weight of the steel piece is relatively large, so it is not suitable for use on lightweight and high-rigidity competition bikes.

This is SHIMANO’s LX571 chainring. The LX571 uses two layers of aluminum alloy gears. The small chainring is rigid. Many people think that aluminum alloy gears will not be strong enough and easily damaged. In fact, this is not the case. Aluminum alloy has very good rigidity after heat treatment, is not easily deformed when pedaling, and can also have high strength when it reaches sufficient thickness. And because of its light weight, it is widely used on high-level off-road vehicles.

The LX disc is manufactured using one-piece die-casting. Due to grade reasons, it still does not use the highest level of processing technology. Therefore, some heavier players may still feel a little soft when using it.

This is RACEFACE’s EVOLVE XC crankset. Its chainring is also made of two layers of aluminum alloy. But you can see that there are obvious differences between it and LX. Its gears use the highest level of processing technology, CNC (COMPUTER NUMBERIAL CONTROL). The thickness, hardness and appearance of the gears have been greatly improved, and they are commonly used on high-end cranksets of various brands.

Let’s take a look at what the top XTR952 crankset looks like. As you can see from the second picture, the XTR chainring and the fixed crank claw are connected together, and the thickest part of the connection is even 7MM, plus the use of ultra-high hardness 7075 aluminum alloy. This relatively extreme approach makes the rigidity of the gear plates reach an astonishing level. Therefore, many DH even use 952 cranksets

Second, crank

If the work on the gears is the same, then what major manufacturers have done on the cranks Each has its own merits. First, let’s look at the crank of a crankset that we are more familiar with. This is the crank of the MC20 crankset. You can see that the crank is forged from a thick piece of aluminum alloy. There is no problem with the strength, but the weight is not so optimistic. So how to reduce weight while ensuring sufficient strength? Come and see how SHIMANO does it.

This is the technology used by SHIMANO on DEORE and above grade cranks. It is called HOLLOWTECH, which is an integrated hollow crank technology. The characteristic of this technology is to evacuate the crank from the inside, so that there is a hollow inside the crank. internal choke, and then use higher-grade materials to ensure the strength of the crank. This technology has greatly reduced the weight of the crankset. It has now developed into the second generation.

So how do other manufacturers respond to SHIMANO’s technology? Let’s take a look at RACEFACE’s approach.

As you can see, the crank design of this crankset is very different from that of the MC20. It has a relatively large hollow on the rear of the crank, and the cross section of the crank is somewhat similar to an I-shape. The technology is called outer hollow design, which is relatively simple compared to SHIMANO's inner hollow design, and due to the vertical cross-section, the longitudinal strength is not greatly affected.

If the design of RACEFACE is not obvious yet, let’s take a look at the crank of PROWHEEL.

The shape of the PROWHEEL crank is similar to a chicken leg, with a large number of hollows on the back. This design greatly reduces the weight, and since the cross section of the crank is not reduced much, the rigidity does not have much impact. , the crank rigidity of the actual use of this crankset is quite good.

If gear technology and crank hollow design are the difference between grades, then the innovation of Zhongzhou technology can be called a qualitative leap. The advancement of transmission system technology can be seen from the way the bottom bracket is used. Advanced or not. Let’s take a look at the mounting holes of the following cranksets. The first is square hole bottom bracket technology. This bottom bracket technology was widely used on cranksets from major manufacturers before 1996. From the lowest grade TY to the highest grade XTR and DA, they are all using this kind of technology. Square hole central axis. The advantage of this kind of bottom bracket is that it is easy to repair and cheap. The disadvantage is that the contact area between the crankset and the bottom bracket is relatively small. When pedaling hard, the crankset will deform and it will not feel strong enough. And in order to ensure strength, a relatively strong axis without hollows must be used, which does not have any advantage in terms of weight. This technology is now backward and is only used on more entry-level systems.

But there are exceptions. Italy’s CAMPAGNOGLO has always insisted on using the traditional square hole bottom bracket, from the lowest grade XENON to the highest grade RECORD that uses carbon fiber cranks. CAMPAGNOLO has always maintained such a tradition in the crankset system, and made his crankset tough by using very good materials and cost-effective processing. This is still very different from the concepts of other manufacturers. The second is SHIMANO's unique OCTLINK splined bottom bracket system. The so-called splined bottom bracket is to make the contact surface between the bottom bracket and the crank into a circular shape, and then make protruding splines on it to fix it, and square holes. Compared with the bottom bracket, the contact area between the spline bottom bracket and the crankset is significantly increased, so that the pressure can be reduced under the same force without making the crank and bottom bracket soft. And under the same circumstances, the weight can be reduced, so that the weight of the entire system can be greatly reduced.

SHIMANO’s spline center axis system has been used on the DA7700 system since 1996. It is a very mature spline system. Because it has 8 splines, it is also called an 8-key system. This system is unique to SHIMANO. The bottom bracket is only produced by SHIMANO. As for the crankset, I know of FSA and compatible models.

The third type is the currently more advanced spline system, called the ISIS system. Compared with SHIMANO's OCTLINK, the number of splines in the ISIS system has been increased from 8 to 10, and the width has also been increased from 5 mm. Increasing it to 1 cm theoretically means higher strength. And this patent is open, and many manufacturers produce ISIS bottom brackets and cranksets. < /p>