As this article is quite technical, we have highlighted all technical terms and provided links to definitions. We want our blog to be accessible to everyone, not just bicycle mechanics or advanced riders, and encourage all readers to submit questions. We’re still finding our voice on our blog, and your input helps us stay in key! Please comment to submit an inquiry and we’ll respond to all questions posted in the comments.

In our last post, we addressed the rising popularity of single speed and fixed gear bikes. These inexpensive and easy-to-maintain builds have become very popular among urban riders, so much so that some choose to convert their geared bicycles into a single speed or fixed gear. Today, we’ll be taking a look at the conversion process.

Our mechanic with his beloved single-speed

One of our mechanics with his lovingly-converted single speed ride. In case you missed the news, our grand opening sale is still going on!

Many geared bicycles may be converted into a fixed gear or a single speed. The easiest frames to convert have horizontal or semi-horizontal dropouts. Since the conversion process can be involved, we do recommend a consultation with one of our mechanics to help you select the proper components for your frame and budget. Our mechanics will also work with you to find a gear ratio that will provide a comfortable ride for your intended use and personal riding preferences.

The cost of such a conversion varies widely, as it is largely dependent on the components that you choose for your build. If you are interested in converting your geared bike to a single speed or fixed gear, you can expect to purchase the following items: a crank, a rear cog and lock ring or a single speed freewheel, a chain, and a rear wheel (either pre-built or built around the hub and cog you choose). We’ll help you choose the appropriate components, and provide a cost estimate based on required labor and the parts you select.

Fixed Gear and Single Speed: What’s the Difference?

Before beginning the conversion process, it’s important to know whether you would prefer a single speed or fixed gear build. Both options have a minimalist drivetrain, consisting of a single chainring on the crank and single rear cog. However, the terms “fixed gear” and “single speed” are not interchangeable. In order to determine whether a bike is a fixed gear or a single speed, all you have to do is look at the rear wheel.

A single-speed is built with the rear cog on a freewheel. The freewheel is mounted on the outside of the hub, so the freewheel and rear wheel move independently of one another. This setup allows the rider to coast, since the freewheel allows the wheel to rotate around the cog whether or not the drivetrain is engaged by the rider. This build requires the use of brakes in order to stop the bicycle.

On a fixed gear (lovingly referred to as a “fixie” by enthusiasts) the rear cog is affixed to the hub on the rear wheel. Fixies do not allow the rider to coast; you must keep pedaling in order to keep moving as there is no mechanism that allows the wheel to move independently of the drivetrain. Since the cog is integrated into the hub, if the drivetrain is not engaged, the rear wheel will not turn, stopping the bike’s momentum. Although an experienced fixie rider will be able to stop their bicycle quickly and reliably, we at Bicycle Roots strongly recommend that all fixed-gear bicycles be outfitted with at least a front brake for safety reasons. Our mechanics will help you to determine which option works best for you.

Which products do your mechanics recommend for a conversion project?

Although the specifics of the build are up to you, our mechanics do have a few favorite components, chosen for their competitive pricing and high durability.

All City hub, cog, and lock ring

All you need for converting your bike to a fixed gear, courtesy of All-City.

For building up your ride as a fixed gear, our mechanics recommend the All City Track Cog ($20) and lock ring ($11). Made of durable steel and available with 12—22 teeth, the All City Track Cog offers a range of gearing options, ensuring you will find one appropriate for your intended use. All City also produces a track hub ($57), suitable for both fixed gear and single speed builds. For fixed gear builds, our mechanics recommend the Velocity Deep V rim ($89.99), available in a variety of colors.

If you prefer a single speed build, we like the ACS Crossfire single speed freewheel ($24.99). Made of cold-forged chromoly for durability, it’s available with anywhere from 13 to 22 teeth and fits 1/8” or 3/32” chains. As single speed freewheels are much narrower than multispeed freewheels, the conversion process requires a wheel built around an appropriate hub. Bicycle Roots offers basic single speed rear wheels fabricated with a Formula hub and Sun rim from $95. For a lighter, sleeker, and sexier option, we recommend the Formula hub/ Weinmann rim build (prices available upon request).

ACS freewheel

ACS freewheel for single-speed conversions.

For both builds, you will need to replace your crank and chain. We recommend the Origin8 Alloy Track 46-tooth crankset ($89.99) for either build option. For the chain, we suggest the KMX BMX 1/8” sprocket Z chain ($13.99), which delivers high performance for all non-derailleur drivetrain systems.

KMC BMX Z chain

Our mechanic’s preferred chain for single speed and fixed gear conversions. Compatible with all cogs, freewheel and cranks with 1/8″ spacing.

Why choose Bicycle Roots for your conversion project?

Bicycle Roots’ mechanics are not only know how fixed gear and single speed bicycles are supposed to be put together, they know how they are supposed to ride. Our mechanics notice the details that other bike shops miss, and we have everything you’ll need to complete the conversion process in stock—even the 27” single-speed wheel. Unlike most bicycle shops in town, we have the 27” single-speed wheel as a stock item rather than a special order, so you’ll be back on the road ready to show off your brand-new drivetrain that much more quickly.

Why does this matter? Well, many conversion projects start out as older road bikes with worn-out components. The cost of replacing gear shifters, derailleurs, a triple crank, and cassette can be prohibitive for some riders, so instead they choose to go single-speed. The only problem? Since road bike standards have changed so much since these frames were produced, modern road bikes use 700 wheels instead of 27” wheels. These wheels have much narrower rims than the old standard, so you may discover that your recently-converted single speed lacks a reliable braking mechanism. The calipers on a brake built for 27” wheels will not be able to squeeze tightly enough and provide adequate friction to reliably stop your bike, so in addition to everything else, you’ll need to purchase new brakes. Since Bicycle Roots carries the single-speed rear wheel as a stock item, we eliminate the need to replace your brakes, keeping costs low and turnaround quick.

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