The internal width of bicycle chains designed for 9/10/11/12 is identical and consequently, it’s possible to use a 9-speed chain with a narrow-wide setup.
However, the outer width of 9-speed chains could be ever so slightly wider than needed for some narrow-wide chainrings. In that case, the wide teeth of the chainring won’t provide as much support due to extra spacing, but the combination should still work fairly well.
Understanding Chain Width
Bicycle chains have an inner and an outer width. The inner width is the distance between the inner plates whereas the outer width is the distance between the external plates. (image below)
The inner width stays the same for 9/10/11/12-speed chains. The outer width decreases as the number of speeds increases.
The reasons for this engineering are:
- To make rear hubs compatible with a multitude of cassettes of various speeds, manufacturers preserve the overall width of cassettes the same. Consequently, it’s possible to mount even an 11-speed cassette on an 8-speed hub.
- To restrict cassette width, manufacturers decrease the distance between the cogs with each gear increase. However, the overall thickness of each sprocket doesn’t change or does so very slightly.
- The chain has to reflect the decreased spacing between the cogs or else its outer plates will rub against the adjacent cogs. To achieve that, the outer plates are made thinner with each gear increase.
- The inner width of the chain, however, stays the same to match the thickness of the cogs.
The table below contains the characteristics of 7/8/9/10/11/12 speed chains:
| Number of Speeds | Inner/Roller Width | Outer width |
| 7 | 2.38mm | 7.3mm (Shimano), 7.1mm (SRAM) |
| 8 | 2.38mm | 7.3mm (Shimano), 7.1mm (SRAM) |
| 9 | 2.18mm | 6.5-7mm |
| 10 | 2.18mm | 5.88-6mm |
| 11 | 2.18mm | 5.5-5.6mm |
| 12 | 2.18mm | 5.3mm |
Conclusion: The inner width of 9/10/11/12 speed chains is 2.18mm. Thus, narrow-wide chainrings designed for those number of gears should be compatible with a 9-speed chain unless specified otherwise for some reason.
What is the purpose of narrow-wide chainrings?
Narrow-wide chainrings were specifically developed to improve chain retention on 1x drivetrains.
1x drivetrains have only a rear derailleur and a single chainring at the front. Chain retention suffers in the absence of a front derailleur, especially when using extreme gear combinations.
One of the ways to remedy this issue is to install a dedicated chain tensioner and/or guide.
The effectiveness of narrow-wide chainrings made tensioners and guides obsolete. After all, many people switch to a 1x drivetrain for its simplicity and clean look. Tensioners and guides take away from those.
How does a narrow-wide chainring function?
Narrow-wide chainrings have teeth of alternating width – one is narrow, and the next is wide.
This pattern is specifically chosen to match the varying width of a chain.
The wide teeth slide between the outer plates whereas the narrow ones go between the inner plates.
As a result, the chain is less likely to drop.
The wide teeth cannot exceed the outer width of the chain.
Most narrow-wide chainrings are engineered for 9,10,11 and 12-speed chains. Thus, the wide teeth of the chainring cannot go beyond the outer width of a 12-speed chain which is the narrowest on the list.
Since the outer width of 12-speed chains is about 5.3mm whereas that of 9-speed chains is approximately 6.5mm, in some configurations, a 9-speed chain will have side gaps.
In most cases, this won’t be a problem, but some manufacturers advise their customers to use a 10-speed chain when the narrow-wide chainring is optimized specifically for 11/12-speed chains.
10-speed chains have an outer width closer to that of 12-speed models but are still compatible with 9-speed drivetrains because they are narrower and don’t rub against the cogs surrounding them.
Frequently Asked Questions
What about using a single-speed chain with a narrow-wide chainring?
It’s possible to use a single-speed chain with a narrow-wide chainring, but the combination makes little sense and isn’t the most stable.
If you have a single-speed chain, then your bike doesn’t have gears. Thus, there is no need for a narrow-wide chainring. You can just get a dedicated chainring for single-speed bikes. It’s gonna be thicker and more durable than a narrow-wide. (read more).
What are the advantages and disadvantages of combining a 9-speed chain with a narrow-wide chainring?
The main advantage is that you will be able to run a 1x drivetrain without the need for chain tensioners and guides. This method saves weight and keeps the setup clean and simple.
The negative is that you will lose gears. Of course, it’s possible to get a 9-speed cassette with a large cog, but the jumps between the gears will be massive and will prevent you from maintaining high cadence (rotations of the cranks per minute). Higher cadence is associated with greater average speed and reduced energy expenditure.
