From single-speed CX, fixed-gear bikes, and city singles to even "mamachari" city bikes.
The world is overflowing with many different kinds of single-speed bikes.
I suspect the reason is that many of them are highly durable, and because they lack delicate components like derailleurs, the structure is simple and maintenance is easy.
The genre of bicycle I have ridden the most is the fixed-gear bike.
Whether for tearing through the city, doing tricks, riding the velodrome, or going on tours.
I believe that riding a single-speed (hereinafter referred to as SS) helped form the foundation of what a bicycle means to me.
Recently, I’ve been hitting the gravel with a fixed gear with Shige-san, and I've started to rediscover the depth of single-speed bikes again.
I think it's a good thing that having a derailleur means you don't have to worry about gear selection. (Of course, I know you do worry about it. Honestly, I'm worrying a lot about it right now.)
With an SS bike, you are basically stuck with the gear ratio you set before your ride.
This is inconvenient, yet fun.
If you ride an SS, you know what I mean, right?
Which gear ratio is right for this route?
Can I get up Norikura with this gear ratio?
I ran this CX race with this gear ratio!
What's the best gear ratio for the city, anyway?
As long as you’re hopping on a bike and pedaling, you’ll always find yourself thinking about gear ratios.
This is deep and fun.
Tire width, bike weight, size of the front chainring, etc.
Many factors intertwine to result in what we call the "heaviness" of the pedal stroke.
This time, I'd like to share my own interpretation of gear ratios to provide a rough guide for everyone!
How to Calculate Gear Ratio
Front Chainring ÷ Rear Sprocket = Gear Ratio
This calculation gives the simple "heaviness" of the gear.
It calculates the number of rotations the rear wheel makes for every single rotation of the pedals.
There are complex factors that intersect with this, but let's leave that aside for now.
My Bike's Gear Ratios
- City Track Bike
47÷17=2.76 - Single-Freewheel for Weekend Rides (Slightly climbing-oriented)
40÷17=2.35 - Gravel Track Bike
40÷21=1.90
These are the gear ratio settings for my single-speed bikes.
I know this might sound like gibberish, so here are some reference values below.
- Keirin racer's gear ratio during a race
3.5~3.99 - Off-the-shelf city single-speed bike
Approx. 2.6 - SSCX gear ratio
Approx. 2.0 - Cycle artistic cycling
1.0
Is it easier to visualize using these as benchmarks?
In terms of gear lightness and heaviness, artistic cycling is the lightest, and it gets progressively heavier as you move toward Keirin and track racing.
Let's examine my gear ratios based on this.
-
City Track Bike [Gear Ratio: 2.76]
For me, a heavy gear is around 3.0.
This setup is lighter than that, allowing me to power up small hills if I have enough momentum.
On flat ground, I can ride with a pretty good sense of speed.
And I’m aiming for a setting that increases the skid patches (which I will explain later), which is important for track bike riders.
-
Weekend Single-Freewheel [Gear Ratio: 2.35]
This ratio is set with the goal of being able to finish a 100km ride with some mountain passes, while sacrificing some speed on flat ground.
Since my road bike's inner-low gear setting is (F:34 ÷ R:28 = gear ratio 1.21), I work pretty hard on the climbs.
-
Gravel Track Bike [Gear Ratio: 1.90]
The bike I use to head into the gravel with a fixed gear, which is what recently reminded me how fun SS bikes are.
Honestly, it might be too light, but there's a reason for this.
The pedals on a track bike keep rotating.
When I need to stop the pedal rotation at an unexpected moment, this gear ratio allows me to stop.
Any heavier, and I run the risk of my body being lifted by the pedals and thrown off, so this setting takes that danger into account.
These are the details of the gear ratios I set.
Yes, I change them depending on the terrain and purpose.
Even for the bike you use for daily transportation, changing the gear ratio could drastically make it easier to use!
If you're curious about your own gear ratio, try counting the teeth on your chainring and figure it out!
Thinking about how you want to use and ride based on the gear ratio you find will open up a better SS bike life!
P.S. Dear Track Bike Rider
To you, who loves track bikes.
If you are a track bike rider who loves to skid, you might have wondered why your tires wear down the way they do.
It's the phenomenon where certain parts of the tire get worn out more than others. I’m sure some of you have noticed this, right?
The cause lies in the rear wheel, which stops in sync when you stop pedaling at certain points.
For example, with a gear ratio of 1.0, one rotation of the pedal is one rotation of the rear wheel, so the tire stops in the same place every time you stop pedaling.
The number of spots where the tire touches the ground when you stop the pedals is called a "skid patch."
Calculating this is quite complex, so I’d like to introduce a very good tool.
All-City has deep roots in track bikes.
Their site has a page called a gear calculator.
It calculates not only your skid patches, but also numerical values including tire size.
It even calculates skid patches for both feet, which is a nice touch.
How many skid patches did your bike have?
There might be a gear ratio that allows you to use your tires longer.
Why not try checking it out?
By the way, Culture Club Kamo-chan’s gear ratio is 3.2.
I don't think I could ride with that gear ratio every day.
He told me it's all about getting used to it, so I’ll try to improve.
Still Skidding ！