A very important thing to consider when choosing a bike with only one gear is the selection of a gear ratio. Deciding to go for a fixed gear or single speed drivetrain will free ourselves of the weight of a derailleur.
This means our two bicycle sprockets, and more specifically their size, will be the main factor that has an influence on our cadence, how fast we accelerate and the highest speed we can get up to. It has a dramatic impact on how comfortable the ride will be.
Moreover, as the name of the drivetrain tells us, we won't be able to change gear while riding. That's why we should think about this parameter carefully when selecting parts for our dream bike.
#1 Cycling cadence
What does this term mean, anyway? Simply put, it's the number of crank revolutions per minute (often recorded as rpm - revolutions per minute), which is how fast we can pedal.
An optimal cadence will allow us to ride faster, smoother, and, most importantly, avoid serious knee injuries.
This value should, most often, be in the range of 70-100 rpm, and it depends on our fitness, the gear ratio, geometry of our frame, and the resulting position on the bike (correct (or not)), and many other factors.
To go deeper into this subject, we can start with this film.
Sunday cyclists tend to ride with a low cadence, while professional cyclists tend to stay in the higher end of the range.
However, this doesn't mean that pedaling, like in the peloton of the Tour de France, will necessarily guarantee us higher speeds. Everything depends on our own abilities. However, it's worth learning how to pedal with a high cadence because it’ll give us better performance and it’ll save our joints.
#2 Bike sprockets
The power of our legs on single-speed bikes is transmitted via the chain and bicycle sprockets - the front (called a chainring) and rear (cog).
By dividing the number of teeth of the former by the latter, we get the ratio value, which is responsible for how many times the wheel turns during one turn of the crank. For example, a chainring, that has 48 teeth together with a rear sprocket, that has 16 teeth, will give us a ratio of 3.0, and a set of 48/17 will give us a value of 2.82.
By delving into the mathematics and counting the circumference of the wheel, we can find out what distance our bicycle will travel in one revolution. How does all this theory translate into reality? The bigger the front sprocket and the smaller the rear sprocket, the bigger the ratio - and vice versa.
# 3 Gear ratio of a bicycle
Getting to the heart of the matter and the consequences of manipulating this value - the higher the ratio, the harder it’ll be for us to accelerate and the lower the cadence we’ll get. However, it'll be much easier for us to maintain high speeds.
A small ratio allows us to ramp up the rpm and get the opposite effect - at the same speed, it'll be easier for us to pedal, but we'll have to "spin" more. If we exaggerate the ratio value one way, our knees will probably hate us. But the other way, we'll get the "hamster on the wheel" effect.
It’s very simple, but, it radically changes the feeling of how we ride - both positively and negatively. Especially on a fixed gear bike.
#4 Skid patches – how not to destroy a tire on a fixed gear in a week
For many people, the biggest motivation behind choosing this type of drivetrain, and not another, was learning how to skid, a technique of braking only using our legs, reserved for the fixed gear.
By locking the rear wheel, we start to skid and "burn rubber", just like a car. There are only two horizontal crank positions (left or right foot forward), that allow us to skid in an effective and, of course, impressive way.
Using the theory of gear ratio, we can come to the conclusion that our tire has no chance of wearing evenly with this form of braking. The areas of tire that come into contact with the ground when skidding are called skid patches, and there may be more or less of them, one to several dozen, depending on the ratio.
The larger the number of patches, the more evenly the bicycle tire wears, and the longer it lasts. We can use one of many calculators available on the internet to calculate this value and analyze the ratio and cadence.
#5 The optimal gear ratio for a fixed gear
When choosing the optimal ratio, we have to consider several factors, such as personal preference, leg strength, or elevation of terrain.
If we live in hilly places, too low a gear ratio will mean that our legs will move at the speed of light everytime we ride downhill, which is an accident waiting to happen. Especially if we're using SPD pedals or straps (read more about this in another of our articles). However, if the ratio is too bigh we'll probably have to get off our bike halfway up the hill and push it.
For flat places, a ratio of 2.6 to 3.0 is ideal for most people. The lower value of this range, with a cadence of 90 rpm, will allow us to ride around 30km/h, while the upper, 34km/h.
If you’re just starting out on your adventure on a single speed or fixed gear bike, a gear ratio of around 2.7-2.8 will be ideal. This is what we install as standard on our bikes. However, if you need another ratio, let us know. We'll easily change this parameter for you.
Starting from a middle value will be the simplest way to find out our needs. After riding for some time, we'll be able to decide whether the ratio is right for us or whether we need a higher or lower value.
If you do happen to change your mind, it’s not going to require a great deal of money or workload. The replacement of the rear cog is enough. Prices start from 10€, and you can do the whole thing yourself or go to abicycle workshop.
#6 Gear ratios - everyone prefers something different
The gear ratio that you decide on for your fixed gear is a very personal thing, and the value of this parameter will be different for every rider.
If you're only at the beginning of this journey, it's best to experiment or go to a bike workshop and ask for help in choosing the right ratio.
Remember also that preferences will change with the development of muscle mass and fitness for each person.
Are you interested in the idea of owning a very nice fixed gear, or are you looking for a fast, versatile bike for the city? Check out our latest range here.
