Generally there are two choices: Single speed setup, or a Multi Gear bike.
Bikes with more than one gear can be further split into: derailleur or Internal hub gears.
In this article we will look at the pros and cons of each system and recommend some bikes within each category.
Why does my Folding Bike need gears anyway?
The reason bikes have gears is to allow the rider to apply even pressure to the pedals at a constant speed no matter whether going up or down hill. You may have experienced your legs spinning fruitlessly going downhill, only to stop dead going uphill on an old bike with no gears?
If your bike remained on the flat you would need no gears at all. If you have ever seen the track cyclists at the Olympics their bikes have no gears! This is because they can set the bike up to run at a constant speed and cruise along at the point of maximum leg efficiency.
As soon as you start to go up hill you need to use far more effort to keep the legs turning at the same speed. This can quickly tire you out, and you need to make this easier in order to ride efficiently over a long time. By changing the gear it means you can rider for longer and more comfortably.
This does mean that you will be traveling slower up hill.
When going downhill the opposite happens, your legs are spinning away, turning fast and there is no power being transferred to the bike. Now you need to move into a higher gear. By engaging a higher gear your legs are generating more power while turning at a lower speed.
To allow for a full range of gradients bikes are often fitted with 20+ gears with a rear cassette capable of selecting 8-10 gears, and the front chain ring adding another 2 -3 sets of rings.
When it comes to folding bikes there are no front chain rings, all the changes happen on the rear cassette (or hub).
Single Speed Folding bikes:
This is simple, there is no need for any gears, and the chain simply loops from the large front ring to the wheel at the back. It’s simple and light weight. If there are few hills or inclines this is a really good option. Single speeds are easy to look after, low cost and can make for the lightest folding bikes.
If you choose fixed speed it means that there is no freewheel. Your pedals will keep turning while the wheels go round, if you go down hill be prepared for your legs to turn quickly!
The two Main Gear Change Systems:
The two main systems are the hub and the derailleur. They are both operated by the rider in exactly the same way, with the gear selector.
The Gear Selector:
On the handlebars there is a leaver or selector that allows the rider to choose which gear they want. This may be in the form of a twist grip – like the accelerator on the motorbike. Or a quick shift selector. The selector is connected to the gears by a cable running through the bike to the rear wheel where a steel wire pulls the gears into place.
Externally this is a single enlarged hub that sits in the middle of the wheel, inside there are different sets of cogs and bearings that allows the gears to be changed. Because all this happens inside a sealed unit there is little maintenance and the chain never has to move from its two rings – improving reliability of both the gears and the chain.
However hubs tend to be more expensive, as they are more advanced than derailleurs. This is balanced by their long life and high performance.
The hub is explored in-depth in this article: For a full article click Here.
With a derailleur there are two functions that are required. With a set of exposed rings that need to be selected the derailleur has to move the chain over the correct set of rings. In addition because all of the rings are different sizes the derailleur also has to take in the slack in the chain as it moves from ring to ring.
As a result the derailleur has to do quite a lot of work, and requires a bit of looking after, keeping it in good condition.
It also means for folding bikes that there is a set of possibly dirty gears exposed that could, when the bike is being carried, transfer oil onto the rider. OF course you can protect the bike with a range of bags such as these folding bike bags
Derailleurs are looked at in detail here.
We have looked at three options summarised in the table below:
|Multi gear – Derailleur||$$||5-7||*|
|Multi Gear hub||$$$||3-9||**|
So what is the best choice Hub, Single Speed or Derailleur for a folding bike?
If your riding is flat and you are not in a hurry then single speed is a great choice.
Should your ride have hills, or you want to get some speed from your bike then you should look at gears.
For a more budget friendly option consider a 6 speed derailleur, or for a more premium option there are some great hubs on the market.
Single Speed Folding Bike Recommendations:
Multi Speed Derailleur Folding Bike Recommendations