Planetary hubs and standard bike derailleurs appeared in our world at more or less the same time. However, the latter quickly took over the entire market and pushed their competitors into oblivion.
However, hub gears such as the Shimano Nexus 8 model used on LOCA Bikes bikes still have their niche and are doing very well, and in recent years, they’ve been gaining more and more followers. So what’s this solution, anyway?
Types of derailleurs
If our bicycle is going to have gears, we basically have two possibilities: ordinary bike derailleur gears and so-called planetary hub gears, which, as the name suggests, the entire system is hidden inside the rear hub.
Most of you know the first option pretty well - the derailleur mechanism, most often controlled by a cable, causes the chain to shift to higher or lower sprockets. This is described in detail in the video below.
But what are planetary hubs? The mechanism here is much more complicated. Planetary gears are used even in cars.
In a nutshell, it’s a system of multiple gears of different sizes, rotating at different speeds. By stopping one component, the rest takes over the load and changes gear.
By using this system properly, we can build a hub up to 14-speed, which covers the same gear range as most modern drivetrains. However, such advanced models can cost as much as a good bike.
Hub gears versus common external gears
Why not just go for the cheaper solution, then? Planetary hubs, in some areas, are much more superior to derailleur gears, while in other areas, they’re much weaker. So it all comes down to the purposes you intend to use the bike for.
- Shifting gears when stationary - unlike derailleur gears, we don't have to turn the pedals for the chain to shift to another sprocket. This works well, e.g., when we are waiting at traffic lights and, beforehand, we didn't shift to a lower gear. For planetary hubs, this isn't a problem.
- Little need for maintenance - hub gears (if it’s a good quality model) are really maintenance-free. Once in a while, they will need to be seen by a mechanic, and in some, models you will have to change the oil every few thousand kilometers, but apart from that, you don't have to do much to them at all.
- A clean drivetrain - no cassette means fewer recesses to clean.
- Long service life - the chain line will always be the same, so if set correctly - then, perfect. This means that the sprockets and chain are likely to have a much longer life compared to conventional derailleur gears.
- Closed design - all the sensitive gears in the hub are sealed in a metal housing, so we don't have to worry about the weather.
- No protruding elements - first of all, depending on your preferences, this has a positive effect on the design of the bike, secondly, we don't have a derailleur which can get damaged in the case of a crash
- No chain drop - the chain is tensioned between two sprockets and has a much smaller margin of movement than derailleur gears, so there’s no need to worry about it falling off.
- Drivetrain price - a single rear cog is much cheaper than a whole cassette.
- The price of the hub itself - the value of a good planetary hub ranges from 100-200€ (Shimano Nexus 8) to more than 1000€ (Rohloff). This isn’t a small amount of money, and it's not going to make financial sense on every bike.
- Few gears - planetary hubs typically have 3 to 8, widely spaced, gears. For flat terrain, this amount is quite sufficient, but when it comes to big changes in elevation, we might run out of gears. Although there are 11 or even 14-speed hubs that already exist (like Rohloff, as we mentioned), the price is deadly.
- The problem with maintenance - due to the very complicated construction, not every bike workshop can properly adjust and repair the gear hub. However, this shouldn’t be a problem in a big city.
- Failures - they are very rare, but once they occur, we'll probably have to get help from a bicycle workshop.
- Weight - planetary hubs are heavy. Even after deducting all the weight saved from the derailleur, cassette, etc, we’ll still be at least a few hundred grams above.
- Chain tension - a simple derailleur takes care of this for us. In the case of planetary hubs, we have to deal with this issue by moving the wheel back in the frame's track ends/dropouts (our bikes have integrated tensioners, which allow you to set the tension precisely).
- Changing the inner tube - due to a cable controlling the gear shifting, which runs directly to the hub, in many models, removing the rear wheel can be quite problematic. At Loca Bikes, we use Shimano Nexus 8 hubs, which will allow you to quickly and intuitively remove the cable when removing the wheel.
- Efficiency - planetary hubs, due to their complex construction, can make you lose more watts than ordinary derailleurs.
Gears in the hub or outside?
What to choose, then? Sure, if you only care about the weight, then a regular derailleur will win this one. Planetary hubs, on the other hand, have a lot of practical qualities: they don't need adjusting, they make it easier to keep the drivetrain clean, and they're enclosed in a sealed hub shell.
A hub with a medium amount of gears such as Shimano Nexus 8 will, therefore, be a great choice for city bikes. An added advantage is the ability to shift to a different gear while stationary, e.g., at traffic lights. Planetary hubs are also a popular choice for bicycle travelers.
Top models from companies such as Rohloff or Shimano are practically trouble-free and provide many years of operation. We also don't need to worry about any additional protruding parts, and the problematic cleaning of the cassette's recesses, or the rear derailleur, especially when we're on a bike trip.
Unfortunately, it isn't possible to service them out in the middle of nowhere and failure usually results in a visit to a workshop, and, in some cases, even sending the hub back to the manufacturer. So hub gears are not suitable for everyone.
Normal derailleur gears are therefore the obvious choice for those looking for low weight, high availability of spare parts, and simple maintenance.
Planetary hubs, on the other hand, will be suitable for our bicycle if we are looking for a less sporty (although this isn't always the case because some people are successfully using a solution like this on their MTB bikes) but a very practical and essentially maintenance-free solution that's very resistant to external factors.
Is a planetary hub something you’d like to try? Or maybe it’s a single speed or fixed gear that’s your dream bike? Visit our website to see the latest range of Loca Bikes city bikes and single speeds.