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An 11-speed chain can be used on a single-speed bike, but only when the rear cog and the chainring are of the correct thickness for the chain.

The standard single-speed chainrings and rear cogs that you find on fixed-gear bicycles, for example, are too thick to be paired with an 11-speed chain.

11-speed Chains Are Not Compatible With Single-speed Chainrings

Chains have an inner and an outer width. The inner width indicates the distance between the inner plates whereas the outer width shows the distance between the external plates (image below).

The inner width of a chain has to respect the thickness of the chainrings and rear cogs. For that reason, it changes little or no at all with each gear increase/decrease. The outer width, however, gets smaller as the number of gears goes up.

The table below contains the inner and outer widths of most chains.

Conclusions

11-speed chains are approximately 1mm narrower (internally) than the standard single-speed models. There are also narrower single-speed chains that have a 3/32″ (2.38mm) inner with. In that case, the difference is smaller – 0.2mm.

The chainrings designed for standard single-speed chains are simply too thick to be combined with an 11-speed chain.

Some models won’t fit while others will cause immense binding and will make the drivetrain very unpleasant to spin. Also, the chain will wear down faster due to the increased contact points between the chainring’s teeth and the plates.

What to do?

The incompatibility of 11-speed chains with dedicated single-speed chainrings and cogs leaves us with the following options:

Option 1: Narrow-wide Chainring + Cassette Cog

This is the most logical combination from a functional and aesthetic standpoint.

What is a narrow-wide chainring?

Narrow-wide chainrings have teeth of alternating thickness. One tooth is narrower while the next is wider. The width alteration follows the chain’s plate pattern and increases chain retention.

The narrow teeth of the chainring go between the inner plates of the chain.

The wider teeth of the chainring go between the outer plates of the chain.

As a result, the chain wraps tightly against the chainring and stays secure. For that reason, narrow-wide chainrings eliminate the need to use a chain guide when running a 1x drivetrain.

Most narrow-wide chainrings are optimized to work with 10/11/12-speed drivetrains. In other words, the thickness of the teeth is such that it offers maximum chain security with no binding.

However, the chainring is only one part of the system.

The rear cog thickness matters too. Standard track/single-speed cogs (image below) are designed for 1/8″ chains and are therefore too thick for an 11-speed chain. (The average track cog is about 1.984mm thick.)

It’s also worth mentioning that a track cog cannot be installed on a standard cassette hub. It requires a threaded one.

Therefore, if you’re converting a multi-speed bike to a single-speed unit, a better option would be to use a cassette cog with 1.8mm thickness.

Cassette cogs can be slid onto the existing multi-speed hub right away. They’re 1.8mm thick and thus equally compatible with 8 and 11-speed chains.

Note: You will also need spacers to secure the cog on the cassette and position it at the right location for a straight chain line. The cog is “sandwiched” between spacers and then secured with a cassette lockring.

The downside of Option 1 (Narrow-wide chainring + Single-speed cassette cog) is that it requires new parts and a fair amount of tinkering to get the setup just right. Other than that it’s rock solid.

FAQ: Do I need a chain tensioner?

Short answer. If the bike has horizontal dropouts, you can tension the chain by pulling the wheel away from the frame. In that case, you don’t need a tensioner. If you have vertical dropouts, a chain tensioner will be necessary (learn more) because you can tension the chain via the rear wheel.

Option 2: Ghetto Modes

If you want to save money, you can also consider the following “ghetto modes”. They’re designed to provide a single-speed bike with an 11-speed chain while minimizing expenses and redundant parts.

a. 11-speed cassette + chain tensioner + 11-speed chainring (vertical dropouts)

In this case, we preserve the original cassette and chainring to save money. The derailleurs are removed to make the setup simpler and lighter. A chain tensioner is needed because the dropouts are vertical and there’s no other way to tensioner the chain.

b. 11-speed cassette + chain tensioner (if needed) + narrow wide chainring

Since narrow-wide chainrings are not all that expensive, you may also consider using one at the front to streamline the setup.