In the eyes of outsiders, people who often ride bicycles usually have a high seat, which is necessary in actual riding. Of course, this height may be a visual illusion.

Bicycle design makes the seat look taller.

Newer road bikes usually adopt a more compact geometry, which means that the upper pipe of the bike inclines downward (as shown below). Such a compact body makes the seat bar more exposed on the upper pipe, which looks taller than the old bicycle.

The handlebars of road cars are particularly low. If two bicycles with the same height saddle, the lower handlebars will obviously give people the illusion that the saddle is higher. The ordinary driver's seat looks higher, which is largely a visual illusion. Similarly, professional drivers' seats look taller, often because their handlebars are lower and their bodies are more compact. After all, the height of the saddle is determined by the length of the rider's legs. Two people with the same leg length set the saddle at the same height, while a bicycle with a lower handlebar will appear to have a higher saddle. The height of the bicycle seat is very important. When your knees are bent, your legs will be weak, while when it is almost straight, your legs will be stronger. The lower bicycle seat allows you to pedal with very bent knees, which makes it more strenuous to ride at the same speed. And the higher saddle (within a reasonable range) keeps your legs in a stronger and more comfortable range. Just like squatting, the lower you squat, the more your legs bend, and the more tired you will feel.

Locking the shoes will also affect the height of the seat. The rider's bike with locked shoes will look taller. Because the cleats of lock shoes are often under the forefoot, connected with the lock pedal and fixed together. Leisure riders, on the other hand, tend to be a little behind the cleats of the locked shoes, which also leads to the fact that the seats of the locked riders look a little higher. Note: For actual riding, you should keep the forefoot above the center of the pedal even if you don't use the shoe lock pedal.

There are various professional and advanced technologies that can do a complete simulation test for you, and customize a fully fitting height (accurate to millimeters). As an ordinary person, it's totally unnecessary. A simple setup will do.

When you ride a bike, put the back of your foot on the pedal, and then ride slowly. If your knees are completely straight, and you are not stepping on the pedal to a certain degree, then this height is almost the right height. If your knees are still bent, raise the seat for debugging.