Condensed Answer: An 11-speed chain is narrower than a 10-speed chain and can therefore be combined with a 10-speed cassette.
Sprocket and Chain Width
With each gear increase, the sprocket thickness and the cog pitch of a cassette decrease.
(The cog pitch is the center to center distance between two cogs.)
The purpose of those adjustments is to make cassettes compatible with a greater number of freehub bodies. Hence why 8/9/10 and 11-speed MTB cassettes and hubs are cross-compatible.
The reduction in cog pitch, however, makes chains designed for fewer speeds non-compatible with cassettes using more gears.
For example, an 8-speed chain is too thick to be used on a 10-speed cassette. It won’t shift effectively, and its outer plates will grind against the adjacent cogs.
Below is a table containing the sprocket width and cog pitch of 8,9,10 and 11-speed MTB cassettes:
| Number of Speeds | Cog Pitch | Sprocket Thickness | Chain Outer Width | Inner Chain Width |
| 8 | 4.8mm | 1.85mm | 7.1mm | 2.38mm |
| 9 | 4.35mm | 1.78mm | 6.5 – 6.7mm | 2.18mm |
| 10 | 3.95mm | 1.6mm | 5.84 – 6.1mm | 2.18mm |
| 11 | 3.9mm | 1.6mm | 5.46 – 5.74mm | 2.18mm |
With each gear increase we observe the following:
- The sprockets get thinner.
- The cog pitch gets smaller.
- The outer width of the chain decreases.
The outer width of the chain decreases to avoid chain rubbing against the surrounding cogs. This is accomplished by relying on thinner outer plates and shorter pins.
The inner width of the chain decreases too when going from 8 to more speeds. The goal is once again to keep the overall width of all cassettes similar.
For that reason, chains designed for more gears are known to be weaker than chains made for fewer speeds.
The Benefits of Running an 11-speed Chain on a 10-speed Cassette
- Silence
An 11-speed chain is 0.36-0.38mm narrower than an original 10-speed chain. However, it has the same internal width (1.6mm).
Since the 11-speed chain is narrower it doesn’t rub against the adjacent cogs and can therefore operate as smoothly as needed.
The narrower profile of 11-speed chains reduces the possibility of chain rubbing and keeps the drivetrain quiet.
- Mud Clearance
One can argue that the extra space left by an 11-speed chain improves mud clearance, and an 11-speed chain is, therefore, better for muddy conditions.
It’s questionable to what extent this takes place, however.
- Potential Money-savings
If you already have an 11-speed chain and want to use it on a 10-speed drivetrain, you can do so and avoid spending extra cash on a 10-speed specific chain.
- More Options
If for some reason, you can’t find a 10-speed chain in store, you can use an 11-speed one.
The Downsides of Running an 11-speed Chain On a 10-speed Cassette
- Weaker
10-speed chains are thicker and therefore potentially stronger than 11-speed chains.
- Slow shifting (potentially)
11-speed chains are slimmer than 10-speed chains. As a result, the derailleur has to move ever so slightly more to initiate a shift. In some cases, this may result in less than ideal shifting speed.
Whether this problem will manifest depends on the rider’s drivetrain parts.
- Less Than Ideal Performance At The Front
An 11-speed chain may result in non-optimal shifting between the chainrings. This outcome isn’t certain, however. Some people complain some don’t.
FAQ: What About a 10-speed Chain on an 11-speed Cassette?
A 10-speed chain will be too wide for an 11-speed cassette. It will cause rubbing, poor shifting, and premature wear of the drivetrain.
To increase the drivetrain’s lifespan and ensure smooth shifting, it’s recommended to stay away from this combination.
FAQ: Can I use an 11-speed Campagnolo chain on a 10-speed Campagnolo cassette?
In general, the answer is yes. The dependencies, positives, and negatives remain the same in the case of Campagnolo components too.
Summary: What You Need To Know
- An 11-speed chain is narrower than a 10-speed chain because the distance between the cassette cogs gets smaller with each gear increase.
- An 11-speed chain has a slimmer profile and will not cause rubbing on a 10-speed cassette.
- The benefits of an 11-speed chain are – silent drivetrain, money-savings (if you already have the cassette.)
- The downsides of combining an 11-speed chain with a 10-speed cassette are slow shifting (potentially) and a higher chance of chain failure (10-speed chains are thicker and thus can be stronger than 11-speed models.)
