What Is Gear Ratio and Gear Inches on A Fixie? (Explained)
In this article, you will learn what a gear ratio is, what gear inches are, and how to calculate the perfect gear ratio for you and your bike.
Published June 13, 2022
You already know your fixed-gear bike has only one gear. But do you know what gear ratio your bike is set to?
In this article, you will learn what a gear ratio is, what gear inches are, and how to calculate the perfect gearing for you and your bike. But before we dive too deep into bicycle terminology and its specifics, we need to understand what a gear ratio is.
A bikeโs gear ratio is the number of teeth on the front sprocket relative to the back sprocket. The number of teeth on the front and rear sprockets together determines the bikeโs gear ratio, which affects how hard or easy it is to pedal and its top speed. Most fixed-gear bikes come standard with a chainring and sprocket of 46 teeth and 16 teeth, respectively, providing a gear ratio of 46:16.ย
A bikeโs gear ratio is the number of teeth on the front sprocket relative to the back sprocket. It also indicates how โeasyโ or โhardโ its gearing configuration is. High gear ratios require more pedal power. Conversely, lower ratios are easier to ride.
Thumbnail for a blog post what is gear ratio and gear inches on a fixie? (explained)
To calculate the gear ratio, you donโt need to calculate the gearโs circumference or anything like that. Just look at the sprockets. The gear ratio is calculated by dividing the number of teeth on the chainring (the big cog) divided by the number of teeth on the sprocket (the rear cog).
The gear ratio of a bike with a 46-tooth chainring and a 16-tooth sprocket is commonly denoted with a colon; 46:16.
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Gear ratio in decimal form
The gear ratio ofย 46:16, for example, may also be represented as 2.875ย when expressed as a decimal. (Youโll get 2.875 if you divide 46 by 16 on your calculator). This implies that, with this 46:16 gear ratio, the rear wheel does almost three (2.875) complete spins with each revolution or rotation of the cranks.
Theย top numbers indicate how many teeth the chain ring has, while the bottom numbers in the leftmost column indicate how many teeth the sprocket has. Dividing the former by the latter gets you the decimal value in the table.
Now weโre going deep into the weeds of gear ratios. Fortunately, the chart below makes it straightforward. This way, you donโt even need to make any calculations. (Note: that we round up the numbers, so you may see a slightly different number on your calculator).
Teeth
40
42
44
46
48
50
52
54
11
3.6
3.8
4.0
4.2
4.4
4.5
4.7
4.9
12
3.3
3.5
3.7
3.8
4.0
4.2
4.3
4.5
13
3.1
3.2
3.4
3.5
3.7
3.8
4.0
4.2
14
2.9
3.0
3.1
3.3
3.4
3.6
3.7
3.9
16
2.5
2.6
2.8
2.9
3.0
3.1
3.3
3.4
18
2.2
2.3
2.4
2.6
2.7
2.8
2.9
3.0
21
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
25
1.6
1.7
1.8
1.8
1.9
2.0
2.1
2.2
28
1.4
1.5
1.6
1.6
1.7
1.8
1.9
1.9
Gear ratio as decimals.
What are gear inches?
Using gear inches is another way to gauge a bicycleโs mechanical advantage. This measurement takes the diameter of the rear wheel (as well as the width of the tire) into consideration.ย
Also, gear inches can be common and useful in certain cycling communities like touring or off-road biking, not so much fixed gear cycling.
Additionally, since the 700c rim diameter is common on almost all adult bicycles, and tire width is such a small difference in this context, we may disregard this element and discuss gear ratios exclusively. Besides, โgear inchesโ is just another way of expressing the gear ratio that takes into account the size of the bikeโs wheels. It doesnโt necessarily provide more or less accuracy in terms of understanding the bikeโs mechanical advantage, it just provides more context for comparing gear ratios between bikes with different wheel sizes.
Are you looking for more advice? Take a look at this video called โWhat Is The Best Fixed Gear Ratio?โย from the Dave Noakes YouTube Channel.
A fixed-gear bike with an average 46:16 gear ratio could be what youโre looking for. You enjoy riding it, but you just wish the gearing was a bit easier so that,ย climbing hills wouldnโt be such a headache.
In this case, you could swap the rear cog for an 18-tooth sprocket. The gear ratio would drop from 2.9 to 2.6 (even tho you added more teeth in the rear cog, you went from a larger gear ratio to a smaller one). You can verify this by looking at the table above.
Alternatively, you can also chainring from a 46-tooth chainring to a 44-tooth one to reduce the gear ratio. However, unlike sprockets, chainrings are often more costly and time-consuming to install.
Of course, if the contrary is true and you want a tougher gear ratioโit may be because your local region is relatively flatโthen youโd either swap to a smaller sprocket or a bigger chain ring.
If you are looking for a rear-wheel cog with a different ratio, check out the ones below.
Below are some commonly asked questions regarding gearing on a fixie, single-speed, or track bike.
What does gear ratio mean on a bike?
Simply put, a bikeโs gear ratio is the number of times the rear wheel rotates for each round of the crank arms (pedals).
Is 46:17 a good gear ratio?
Most stock fixed-gear bikes are sold with 46:16, good for most people. But 47:17 is also commonly considered a balanced gear ratio that provides some compromise between climbing, descending, and flat terrain. This would be ideal if the area isnโt excessively hilly and has a mix of all terrains. This ratio gives about 74 gear inches.
What is a 1-to-1 gear ratio bike?
A 1-to-1 ratio means the sprockets on the chainring and the rear cog will have equal teeth. This is relevant to geared bikes, not fixed-gear bikes.
Conclusion
So thatโs it, Gear ratio demystified. And the handy chart makes it even easier to understand! So, what gear ratio configuration are you using? Let us know in the comments below (I read and reply to every comment). If you found this article helpful, check out our full blog for more tips and tricks on everything fixie. Thanks for reading, and stay fixed.
This article covered what gear ratio is, what gear inches are, and how to calculate the perfect gearing for your bike. Here are some key takeaways:
Key takeaways
Most fixed-gear bikes come standard with a chainring and sprocket of 46 and 16 teeth.
Gear inches are more accurate than gear ratios, but theyโre less often used.
You can change your gear ratio by swapping your bicycleโs rear cog or chainring.
Hey there! My name is Bradley, and I've been riding fixed for years. I love all the joy and pain that comes with this unique style of cycling and the passionate community that drives it. If you love fixed-gear bikes, this is the place for you.
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2 thoughts on “What Is Gear Ratio and Gear Inches on A Fixie? (Explained)<h2 class="post-excerpt">In this article, you will learn what a gear ratio is, what gear inches are, and how to calculate the perfect gear ratio for you and your bike.</h2>”
So, have you found a suitable gear ratio? Let me know, I read and reply to all comments.
Way up at the top, you say “This implies that, with this 46:16 gear ratio, the wheel does over 3 (2.875) complete spins with each revolution or rotation of the cranks.”
I am still learning about gears and gear ratios, but 2.875 is not “over 3”, it is “almost 3”. What am I missing?
So, have you found a suitable gear ratio? Let me know, I read and reply to all comments.
Way up at the top, you say “This implies that, with this 46:16 gear ratio, the wheel does over 3 (2.875) complete spins with each revolution or rotation of the cranks.”
I am still learning about gears and gear ratios, but 2.875 is not “over 3”, it is “almost 3”. What am I missing?