The derailleur is a crucial element that helps with climbing hills and makes riding a bike easier. We often compare this part of the drivetrain to a car's gearbox. Before buying our bike, we often also face the challenge of choosing the right derailleur. In addition to the traditional derailleur, we can also find versions built into the hub. Standard derailleurs, also known as external derailleurs, are divided into front and rear. They also have additional sprockets. Models hidden in the rear hub are called "planetary derailleurs," and I will try to describe this type of derailleur here, in terms of its advantages and disadvantages. We use them on our bikes and, unlike many repair shops, we regularly service them. Hub derailleurs are not magic!

Hub derailleur, also known as planetary gear

The planetary gear shifter is hidden in the rear hub, so all visible components are enclosed, protecting them from dirt and damage like a traditional derailleur. Furthermore, adjusting a hub derailleur is usually very simple – simply adjust the special indicators in the selected gear (usually in the middle of the range) so that they align due to cable tension. Another key advantage is that changing gears doesn't have to be done while riding, but can also be done while stationary or at traffic lights. Importantly, the device's simplicity allows for convenient and, above all, simple operation, with only one shifter to change gears. These derailleurs are considered maintenance-free, so it's difficult to find a repair shop that knows them well. However, it's important to remember that a season-long inspection and oil or grease change is a reasonable minimum. It would certainly be simpler and cheaper to visit a repair shop every season than to buy a new derailleur, especially since this requires re-bracing the sprocket . The most popular planetary hubs

Nothing is for free - weight!

The weight of the derailleur itself can also be a drawback. Because it's mounted exclusively in the rear hub, it can add about half a kilogram to a kilogram to the standard version. However, it's important to remember that planetary gears are typically used on city bikes . They have a significant starting weight, so it's possible that half a kilogram won't make much difference to the user. Models with more gears also significantly increase the bike's price.

Planetary gear - varieties

Multi-speed hubs can usually be divided into three types, based solely on the number of gears: three-speed, five-speed, and seven-speed. Of course, city riding isn't exactly competitive. Nevertheless, a few trips up the Vistula River embankment in Warsaw are enough to appreciate the importance of shifting gears. Without good physical condition, a three- or five-speed hub may prove simply impossible. A seven-speed hub may be a better solution in such situations, but the investment costs are slightly higher. As you can see, the planetary gear shift offers many advantages, but it's also not without its drawbacks. Therefore, every cyclist should determine their own preferences and riding style before purchasing a bike. Nevertheless, for those who have decided to buy a city bike, I can highly recommend models with a hub gear. While riding, it's not exposed to dirt or damage, ensuring a long service life.