Condensed Answer: For optimal performance, it’s best to use components part of the same groupset.
Nonetheless, people have been mixing SRAM eTap derailleurs with Shimano chains, cassettes and chainsets successfully.
At the end of the day, the derailleur doesn’t know what chain, cassette, and chainrings it’s operating with/on.
Shimano Components That Can Be Combined With SRAM eTap
SRAM eTap derailleurs are designed for 11 and 12-speed cassettes and subsequently require an 11 or 12-speed chain.
Note: The chain on a bicycle gets narrower as the gears increase because the cassette becomes “denser” (there are more cogs fitted within the same space).
If the chain doesn’t get slimmer with each gear increase, it will rub against the adjacent cogs.
As long as the chain of choice matches the number of gears on the cassette, in this case 11 or 12, it will work on a drivetrain equipped with eTap derailleurs.
Therefore, Shimano 11 and 12-speed chains are an option too.
If the number of cogs on the cassette corresponds to the number of gears that the rear derailleur is designed for, and the biggest tooth doesn’t exceed the maximum tooth capacity of the derailleur, the cassette will fit just fine into the system.
You can find the maximum range of eTap rear derailleurs in the table below:
|Model||Number of Speeds||Cassette Range|
|SRAM RED ETAP||11||11-32T|
|SRAM FORCE ETAP AXS (33t max)||12||11-33T|
|SRAM FORCE ETAP AXS (36t max)||12||10-36T|
|SRAM RED ETAP AXS (33t max)||12||10-33T|
|SRAM RED ETAP AXS (36t max)||12||10-36T|
|SRAM RIVAL ETAP AXS||12||10-36T|
The eTap front derailleurs support 2x drivetrains and can be combined with 2x cranks of other brands.
For best results, it’s recommended to use cranks that match the drivetrain’s number of gears.
Even though it’s possible to mix chainrings and chains of different speeds (e.g., matching 11-speed chainrings with a 10-speed chain), the results are optimal when both components are engineered for the same number of rear cogs because the chainrings’ teeth patterns vary according to the gearing.
Also, in some cases, the distance between the two chainrings is smaller when the drivetrain uses more gears. The goal of this engineering is to ensure a better chain line. And since more speeds equal a “denser” cassette, the chainrings are moved closer together too.
In practice, however, it’s questionable to what extent this tweaking makes a perceivable difference.
The table below shows SRAM eTap’s front derailleurs and the number of chainrings and speeds that they support.
|Model||Number of Chainrings and Speeds|
|SRAM FORCE ETAP AXS||2×12|
|SRAM RED ETAP||2×11|
|SRAM RIVAL ETAP AXS||2×12|
Shimano Components That Cannot Be Used With SRAM eTap
Shimano’s electronic shifters and SRAM’s eTAP derailleurs are incompatible because they use different connectors.
The only way to make the combination work is to do some serious modifications which most people won’t be comfortable performing given the complexity of the procedure and the price of the components.
Also, any sort of hacking would immediately void the warranty of the parts.
For that reason, it’s best to stick with SRAM’s proprietary shifters when using the eTAP derailleurs.
It’s best to use matching brakes, levers, and calipers. Mixing brands can result in poor performance whether you use rim or disc brakes.
- Caliper Brakes
Shimano’s caliper rim brakes have longer arms and subsequently more mechanical advantage a.k.a. leverage.
The mechanical advantage of a tool is measured by dividing the input displacement by the output displacement.
The greater the input displacement, the greater the leverage.
This may sound a little confusing because extra leverage is associated with diminished effort.
However, the principle becomes apparent when you observe the operation of a simple lever.
In the image above, the “B” part of the lever has more leverage because it’s longer.
The maximal travel of the “B” end is greater than that of the short “A” end which has a lower leverage.
In the world of bike brakes, this translates to the following:
The more leverage a brake has, the more its lever moves per 1mm of brake arm movement. To compensate, brakes with more leverage pull more cable. Otherwise, the lever may complete its travel before the brake has fully grabbed the rim.
SRAM’s rim brakes have lower leverage and subsequently operate with a shorter pull.
If you combine Shimano brakes with SRAM levers, you will be pairing a brake that’s designed for a longer pull with a lever that pulls less cable.
To compensate, the brake arms will have to be moved super close to the rim so that the lever doesn’t have to trigger as much movement. The result is poor modulation (control over the braking force).
- Hydraulic Brakes
Shimano and SRAM hydraulic brakes rely on different fluids. Shimano uses mineral oil whereas SRAM brakes work with DOT fluid.
Since the hydraulic seals are different for each type of fluid, it’s not recommended to mix brands.
If you combine a Shimano hydraulic brake with a SRAM lever, the seals will get damaged and the brakes will simply fail.
Conclusion: If you’re going to use SRAM eTap’s brake levers, combine them with the appropriate SRAM brakes.
What Are The Risks of Mixing Shimano and SRAM Parts?
The risks vary from minor, impossible to perceive, underperformance to complete failure which would be the case if you mix the brake systems.
That said, it’s also possible to lose your warranty when combining non-SRAM parts with SRAM products.
Summary: What You Need To Know
1. For ultra-optimal performance, it’s recommended to stick with group set parts produced by one manufacturer.
2. It’s possible to use a Shimano chain, cranks, and cassettes with SRAM eTap components without experiencing degraded performance.
Each of the components should be designed for the same number of speeds. (e.g., 11-speed chain + 11 speed cassette…etc.)
3. You cannot use Shimano shifters with SRAM’s electronic derailleurs because the connectors are different.
4. The brakes, brake levers, and calipers should be made for one another. Otherwise, the brakes may fail and put the rider in a dangerous situation. If you have SRAM levers, use SRAM brakes; If you have Shimano brakes, use Shimano levers.