Bike Speeds and Hub Gears Explained
The world of bike gears can be confusing for even the most veteran cyclists. While the mechanics behind these systems are fairly easy to understand, marketing departments can often derail this with misleading labels, which do not necessarily reflect the practical gears offered by that model.
To untangle this unnecessarily complex field, ARCC Bikes is here to shed some light on gears, explaining also the difference between different drivetrains, and when to use them.
How to differentiate between bike speeds
Bike 'speeds' usually refer to the number of gears that a drivetrain offers. They can range from 1 to as high as 30+, although as will be discussed further, this number does not always reflect how many gears are actually available.
As a rule of thumb, the number of gears is determined by the cassette and the chainring. That is the cluster of sprockets at the rear of the drivetrain and the toothed ring at the front attached to the crank.
The 'speed' of a bike is calculated by the number of rear sprockets multiplied by the number of front chainrings. For example, a double-chainring with a 2-speed cassette will be a 4-speed drivetrain, while a single-chainring with a 11-speed cassette would be an 11-speed.
What do gears do?
Gears allow the user to maintain a comfortable cadence (rate of pedalling), regardless of the terrain or gradient.
The difference each gear will have on your cadence is dictated by the ratio, between the paired number of teeth on the sprocket and the number on the chainring.
The high gear, sometimes called the big gear by cyclists, is the ratio achieved by combining the largest front chainring with the smallest rear sprocket. Meanwhile the smallest front chainring size combined with the largest rear sprocket results in the lowest available gear.
These are just two 'speeds'. Those in between are achieved by completing the remaining sprocket-chain ring combinations. That said, in some multi-geared set-ups, (ones with multiple chain rings and cassettes), having ‘overlapping’ gear ratios is generally unavoidable.
So although bikes can be marketed with high speed numbers, some of these offered speeds will be technically appear twice due to the same gear ratio being achieved with different sprocket and chainring teeth combinations.
What gear configuration for what situation?
In general, terrain/gradient determines what gears are most suitable. For example, with the two speeds described above, the high gear is best used when descending or riding at high speeds, while a low gear helps on steep gradients.
Therefore a bike having lots of gears is not about making it faster- it is instead for giving the user a range of choice when tackling gradients.
For example, if you live in an area that has varied terrain, a high-speed bike may be the better choice to give you more options.
Meanwhile, if you do most of your riding in a place that is generally flat, a bike with less gears is probably best as you will not need to change them often. Indeed, this is why single-speed bikes are very popular among commuters, whose route to work is generally flat.
What drivetrain options are available?
There are numerous gear systems on offer, each with their own advantages and disadvantages. Indeed, alongside traditional derailleurs for single, two and four speed bikes, like the SRAM and Sturmey-Archer systems, ARCC also stocks hub gears with high gear numbers from globally-renowned brands like Shimano and Rohloff.
Ranging from 8- to 14-speeds, hub systems house the gears internally, better protecting them from the elements than derailleurs. Robust and dependable, hub systems also allow you to change gear without having to pedal, which is a blessing when stopped at lights.
The only real disadvantages are the added weight of the hub gear housing and the price of these state-of-the-art systems, so it is advisable to consider what gearing is best suited to your cycling needs.
ARCC is adept at fitting all kinds of gear systems, and has even fitted a Rohloff to a Brompton.
For more information on what gear systems are on offer at ARCC, see our bike listings. Our technicians are always happy to answer any queries you may have on bespoke fittings and current gear systems on ARCC models.