Condensed Answer: It’s possible to combine a 12-speed crankset with an 11-speed cassette, but you have to be aware of the following peculiarities.
- Shimano’s 12-speed chains and chainrings have unique dimensions. Thus, it’s not recommended to use an 11-speed chain with 12-speed Shimano chainrings, although in some cases the combination can still work, but it’s not optimal.
The viable combinations for Shimano are:
- 12-speed cranks
- 12-speed chain
- 12-speed front derailleur
- 11-speed cassette
- 11-speed rear derailleur
- Campagnolo 12-speed cranks can be combined with 11-speed cassettes from the same brand.
- SRAM’s 12-speed MTB cranksets should also work with an 11-speed cassette.
However, SRAM’s Flattop (the road/grave line) 12-speed line is only compatible with SRAM’s 12-speed AXS cranksets.
To learn more, consider reading the longer explanation below.
Factors For Compatibility Between 12-speed Cranks and 11-speed Cassettes
- Chain width
The difference between 11-speed and 12-speed cranks isn’t massive. The main issue to be concerned with is the outer width of the chain.
Chains have an inner and outer width. The inner width is the distance between the inner plates; the outer width is the distance between the outer plates.
As the number of speeds (cassette cogs) increases, the outer width of the chain decreases.
Why?
- Cassettes slide onto the freehub body of the rear hub.
- Manufacturers limit the width of the freehub body and do not increase or decrease it unless necessary.
- The overall width of the cassette is also minimized so that the same hub can accept cassettes designed for more gears.
- Since the width of the cassette is restricted, the only option is to decrease the spacing between the cogs with each gear increase.
The outer width of the chain has to reflect the changes above.
In other words, the outer width decreases with each gear increase. This is accomplished by making the outer plates of the chain thinner. The inner width cannot be decreased drastically because the overall thickness of the cogs is the same.
If the outer width is not decreased, the outer plates will rub against the adjacent cogs.
The data below reveals the cog pitch of 11 and 12-speed cassettes (the cog pitch is the center-to-center distance between two adjacent cogs) as well the inner and outer width of 11 and 12-speed chains.
| Number of Speeds | Cog Pitch | Sprocket Thickness | Chain Outer Width | Inner Chain Width |
| 11 | 3.9mm | 1.6mm | 5.46 – 5.74mm | 2.18mm |
| 12 | 3.55mm | 1.6mm | 5.15-5.25mm | 2.18mm |
Conclusions: 12-speed chains are narrower than 11-speed chains. The width of all chains varies slightly among manufacturers, but in general 11-speed chains are about 5.5mm whereas 12-speed chains are 5.3mm.
In percentage, the difference is only 3.7%, but it’s still enough to cause shifting issues.
When combining an 11-speed cassette and 12-speed cranks, it’s possible to use both 11-speed and 12-speed chains.
The 11-speed chain is made for the cassette whereas the 12-speed chain is narrower than the 11-speed models and therefore won’t cause rubbing.
The downside of using a 12-speed chain is that the shifting might get ever so slightly delayed because the rear derailleur has to travel slightly more to reach the chain. However, it’s questionable whether a human can even perceive the lag.
If an 11-speed chain is used, there’s a chance that it will rub against the front derailleur’s cage. This outcome is more likely when using extreme gear combinations causing cross-chaining.
It’s impossible to tell whether this will happen to you because each setup is different. In most cases, however, it should be possible to push back the front derailleur using the limit screws to eliminate rubbing. If the derailleur has a trim function, it will help too.
- Chainring and Chain Profile
Shimano 12-speed chains and chainrings have a unique profile designed to improve chain retention and speed up shifting. The technology is called Dynamic Chain Engagement.
For that reason, it’s not recommended to use an 11-speed chain on 12-speed Shimano chainrings. The combination is not necessarily bad, but the performance will not be optimal.
Given the data above, the following combinations become viable:
- 12-speed chain
- 11-speed cassette
- 12-speed chainrings
- 12-speed cranks
- The Front Derailleur Is Important Too
The front derailleur is not part of the crankset but is influenced by it.
For example, Shimano’s 12-speed front derailleurs are designed for Shimano’s special 12-speed architecture. Combining a 12-speed front derailleur with an 11-speed chain is therefore not considered optimal in a Shimano ecosystem.
However, in the case of Campagnolo and SRAM Eagle, it’s possible to use a 12-speed front derailleur with both 11 and 12-speed chains.
Let’s summarize the final combinations that have the highest chance of working
Shimano:
- 12-speed chain
- 11-speed cassette
- 12-speed chainrings
- 12-speed cranks
- 12-speed front derailleur
Possible problems: The chain may be a bit too tight for the cassette and the shifting might be somewhat “metallic”. Whether this will happen cannot be said with certainty because many setups are possible.
SRAM Eagle or Campagnolo
- 12/11-speed chain
- 11-speed cassette
- 12/11-speed chainrings
- 12-speed cranks
- 12/11-speed front derailleur
Possible problems: Slightly slower response rate when using a 12-speed chain. If an 11-speed chain is used, it may not wrap as tightly around 12-speed chainrings.
Note: SRAM has two separate 12-speed standards.
The road/gravel standard is Flattop whereas the MTB standard is Eagle. SRAM’s 12-speed Flattop chains have a unique size and are therefore compatible only with SRAM’s 12-speed AXS road groupsets. They are not compatible with SRAM Eagle drivetrains or drivetrains from other brands.
Combining a 12-speed Flattop chain with an 11-speed cassette is therefore not recommended as the chain’s unique size will cause poor shifting.
It’s also not recommended to use 12-speed Flattop chainrings with an 11-speed chain.
