The difference between different speeds of mountain bikes many novices who have just bought mountain bikes don't know the difference between 21 speed, 24 speed and 27 speed. Or just know that 21 speed is 3x7, 24 speed is 3x8, and 27 speed is 3x9. I also asked if 24 speed is faster than 27 speed. If someone rides an old-fashioned mountain bike with an iron frame and runs behind others, knowledgeable riders will tell you not to run with them. They are 27 speed and you can't run with them. In fact, speed ratio just gives drivers more choices. Speed depends on their own leg strength, endurance and skills. As long as you have great strength, 21 speed is no slower than 24 speed! How many miles can a mountain bike ride? Theoretically, under the same stepping frequency, 27:24 runs faster and 24:21 runs faster. But in fact, when pedaling with high transmission ratio, the pedal frequency will naturally decrease, and the pedal frequency and speed will naturally decrease. Otherwise, some novices bought a car and said, my car is good. Why does my car pedal so hard? The reason is that I didn't choose a transmission ratio suitable for you when riding.
Let's talk about my personal understanding of the difference between 21 speed, 24 speed and 27 speed
First look at the parameters:
21 speed gear plate 48-38-28 flywheel 14 ~ 28
24 speed gear plate 42-32-22 flywheel 11 ~ 30 (11 ~ 32)
27 speed gear plate 44-32-22 flywheel 11 ~ 30 (11 ~ 32)
The number of gear discs divided by the number of flywheel is the transmission ratio
The maximum transmission ratio of 21 speed is 3.43 and the minimum transmission ratio is 1
24 speed maximum transmission ratio 3.82, minimum transmission ratio 0.73 (0.69)
27 speed, maximum transmission ratio 4, minimum transmission ratio 0.73 (0.69)
From this, we can see the difference between them. 27 and 24 speed have a larger or smaller transmission ratio than 21 speed, which can make you run more and save more effort. Because the gear disc of 24 is different from that of 21, a smaller gear disc can obtain a lighter transmission ratio, which shows great advantages when climbing. 24 speed vehicles can reach a transmission ratio of 1.07 even when using 2x1 speed ratio. If the flywheel is 11 ~ 32 vehicles, it can reach a transmission ratio of 1 (the minimum transmission ratio of 21 speed is 1) Therefore, the advantage of the 24 speed car over the 21 speed car is not only in the fastest gear, but also in the slowest gear, which makes it easier and more awesome for you to walk on mountain roads. Ordinary novices just want to pedal faster at 24 speed than at 21 speed. Few people may divide the number of teeth of each gear disc and flywheel to see what the difference is.
The flywheel of a 27 speed car is generally the same as that of a 24 speed car. The difference is that the largest one of the front gear discs is adjusted from 42 to 44. In this way, the nine speed ratios under the big gear disc are larger than those of 24 speed, which is suitable for people with good physical strength. Another 24 speed or 27 speed. With its different grades, various parts of the car are upgraded to better models, which is also the difference.