If you're riding or just 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.' It 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 a personal choice and depends on individual preference. It’s an integral part of your relationship with your fixed gear bike. For city riding, the typical gear ratio ranges from 2.7 to 3.1. If the ratio is too high to your leg strength, pedaling can be difficult; if it’s too low, it might feel unsatisfying.
Finding the right gear ratio balance is essential. Below, we’ve attached a gear ratio chart to help you choose the best option for you.
Next is 'Skid Spots.'
'Skid' is a trick unique to fixed gear bikes, similar to a drift, takes advantage of the fixed gear mechanism .
'Skid Spots' refer to how many points on the tire that wear down when skidding 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, creating a single skid spot. It causes the tire to wear down at one specific point. More skid spots mean more even tire wear, extending the tire's lifespan. Simply put, more skid spots are better.
Calculating skid spots can be a bit tricky, 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 indicate our recommended gear ratios.
You’ll notice that a 17T cog is highly versatile and making it easier to find the optimal gear ratio.
Finding 'the right gear ratio' for yourself may require changing parts a few times..
To minimize trial and error, we recommend:
① Start with a 17T cog.
② Adjust your chainring size as needed either increasing or decreasing it.
This approach should help you reach your ideal gear ratio more efficiently.
By the way, the common gear ratio of '48T/16T' found in many complete fixed gear bikes translates to a 3.00 gear ratio 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 48T/17T combination, resulting in a 2.8 gear ratio and 17 skid spots. A slightly lower gear ratio is preferable for mastering skidding, and 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 effectiveness. Therefore, we recommend investing in a high-quality cog for long-term use.
Let me introduce you to some recommended cogs
This is a classic cog option available in a wide range of tooth sizes.
This model is a chrome-plated version of the DLX. While it costs twice as much, it’s more popular for its enhanced durability and smoother chain movement.
This is a gold-plated version of the DLX with a protective coating. It costs three times more, but consider it three times as efficient. This special version with color-coded ink fill based on the number of teeth.
The BROTURES original track cog is resistant to rust thanks to its stainless steel construction. Machined using CNC technology, the cog features bold cutouts that balance strength with weight reduction. Incredibly affordable yet with flawless precision. Perfect for making your first gear ratio change.
From New Zealand-based Velobike, this cog delivers high quality at an affordable price, making it an excellent choice for those looking to experiment with gear ratios.
SHIMANO SPROCKET REMOVAL TOOL TL-SR22
If you’re getting used to ride a fixed gear bike, and want to try skidding, or if your current gear ratio feels unsatisfying or too heavy, feel free to contact us. We also welcome bikes purchased from other stores, so don't hesitate to reach out for advice.