Understanding Gear Ratio and Skid Spots i...
If you're riding or starting to ride a fixed gear bike, two essential concepts to familiarize yourself with are 'Gear Ratio' and 'Skid Spots.'
First, let’s talk about 'Gear Ratio.'
This refers to how many times the rear wheel turns for each rotation of the pedals. It's calculated as 'Number of Teeth on Chainring ÷ Number of Teeth on Cog = Gear Ratio.' For example, with a chainring of 48T and a cog of 16T, the calculation is 48 ÷ 16, resulting in a gear ratio of '3.00.' This means for every pedal rotation, the rear wheel turns exactly three times.
The gear ratio also affects the 'feel' of pedaling - how heavy or light the pedals feel.
Finding the perfect gear ratio is subjective and varies from person to person. It’s an integral part of your relationship with your fixed gear bike. The typical gear ratio for city riding is around 2.7 to 3.1. If the ratio is too high relative to your leg strength, it can be challenging to pedal; too low, and it might feel unsatisfying.
Finding the right balance in gear ratio for yourself is key. Below, we’ve attached a gear ratio chart to help you determine the best one for you.
Next is 'Skid Spots.'
'Skid' is a trick unique to fixed gear bikes, akin to a drift, leveraging the nature of the fixed gear.
'Skid Spots' refer to how many points on the tire get worn when you skid at the same pedal position. For example, with a gear ratio of 3.00, the rear wheel turns exactly three times for every pedal rotation, resulting in one skid spot. The tire will wear down at one specific point. More skid spots mean more even tire wear, maximizing the tire's lifespan. In simple terms, more skid spots are better.
Calculating skid spots can be a bit complex, so refer to the quick-reference chart below.
We've also compiled a table of chainring and cog combinations with '10 or more skid spots' that are suitable for city riding, with gear ratios between 2.7 and 3.1.
The areas highlighted in blue represent our recommended gear ratios.
You’ll notice that a 17T cog is versatile and makes finding the optimal gear ratio easier.
Finding 'the right gear ratio' for yourself may require changing parts a few times..
To minimize trial and error, we suggest:
① Start with a 17T cog.
② Adjust your chainring size accordingly (either increase or decrease).
This approach should help you reach your ideal gear ratio more efficiently.
For instance, the common gear ratio of '48T/16T' found in many off-the-shelf fixed gear bikes translates to a gear ratio of 3.00 and only one skid spot. If you're riding a bike with this setup, consider switching to a 17T cog first.
This change will create a combination of 48T/17T, resulting in a gear ratio of 2.82 and 17 skid spots. A slightly lighter gear ratio is preferable for mastering skidding, and it also allows for optimal tire usage. Once you have a 17T cog, it's likely to be a long-term component due to its versatility and efficacy. Therefore, we recommend investing in a quality cog for prolonged use.
Let me introduce you to some recommended cogs
This is a classic cog choice with an extensive range of teeth options.
This model is a chrome-plated version of the DLX. Though it costs twice as much, it’s more popular due to its enhanced durability and smoother chain movement.
This is a gold-plated version of the DLX with a coating. It’s priced three times higher, but think of it as thrice as efficient. It’s a special version with color-coded ink fill based on the number of teeth.
A carbon-made track cog from the swiftly rising brand Digirit, known for its remarkable durability even under intense training regimes and virtually silent operation.
A popular, ultra-lightweight titanium cog, significantly lighter than the EURO-ASIA GOLDMEDAL, thanks to extensive material reduction.
Special tools are required for installing the cog. It’s an essential tool for every fixed gear rider.
From New Zealand-based Velobike, this cog offers high quality at an affordable price, making it an excellent choice for those experimenting with gear ratios.
SHIMANO SPROCKET REMOVAL TOOL TL-SR22
For those getting used to fixed gear riding and interested in trying skidding, or if you find your current gear ratio unsatisfying or too heavy, feel free to consult us. We welcome bikes purchased from other stores as well, so don't hesitate to reach out for advice.
Junki
BROTURES YOKOHAMA
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