Condensed answer: R7000 and 5800 are Shimano 105 11-speed groupsets. Consequently, they’re compatible with each other because the derailleurs’ shift ratios and the shifter’s cable pulls match.
Rear Derailleurs and Shifters
To understand the possible source of incompatibility between a rear derailleur and a rear shifter, one has to become familiar with the following principles and terms.
- Index Shifting
Modern shifters are indexed. In other words, their movement is segregated into separate clicks. Each click indicates a gear change (the chain moves from one cog to another).
Each click pulls or releases a predetermined amount of gear cable. This is the so-called cable pull and depends on the following factors – number of speeds, shifter manufacturer, and bike type (MTB or road)
Once the cable is pulled or released, the rear derailleur moves up or down the cassette. The movement of the rear derailleur is pre-determined too.
Each derailleur has a rear shift ratio. The rear shift ratio shows how much the derailleur moves per 1mm of cable pulled or released by the shifter. For example, if the rear shift ratio is 1.4:1, the derailleur moves 1.4mm per 1mm of cable pull.
The purpose of this engineering is to ensure that the derailleur moves to the right location to trigger a shift and maintain the chain tension in that gear.
Just like the cable pull, the rear shift ratio depends on the number of speeds, the bike type, and the manufacturer.
If the derailleur is replaced with another one that has a different rear shift ratio, shifting will become problematic, and sometimes the combination will fail completely.
The rear shift ratio of Shimano Road 11-speed derailleurs is about 1.4. The cable pullo of Shimano Road 11-speed derailleurs is 2.7mm.
This is the case for the new (r7000) and the older (5800 groupsets). Consequently, it’s possible to mix r7000/5800 derailleurs and r7000/5800 shifters.
In fact, all Shimano 11-speed Shimano road derailleurs and shifters are interchangeable precisely because they all have matching rear shift and cable pull values.
However, there could be an incompatibility between the derailleur and the cassette that will be clarified further down the article.
Conclusion: R7000 and 5800 shifters and rear derailleurs are compatible with each other.
Rear Cassette and Rear Derailleurs
Rear derailleurs have a maximum large cog capacity. If that number is ignored, the derailleur will either fail to reach the largest cog or shift slowly and poorly.
Even though both R7000 and 5800 derailleurs are designed for 11-speed cassettes, not all derailleur models have the same cage length.
If the derailleur has a short cage, it won’t work with a large cassette such as 11-34. If you have a similar cassette, you need a model with a long cage to enjoy smooth and accurate shifting.
Front Derailleur and Front Shifters
The same principles apply to the front derailleurs and shifters as to the rear.
The compatibility chart on Shimano’s website confirms that R7000 front shifters are compatible with 5800 derailleurs and vice versa.
Conclusion: R7000 and 5800 front derailleurs and shifters are compatible.
The 5800 series relies on standard mechanical caliper brakes whereas the 7000s series includes hydraulic disc brakes.
It’s possible to use 5800 brakes with R7000’s brake-shifters designed for mechanical calipers.
It’s also possible to combine R7000 brakes with 5800 mechanical levers.
However, you will not find hydraulic brakes or levers in the 5800 series.
Conclusion: The mechanical brakes and levers from both series are compatible.
Bottom Bracket & Cranks
Both the R7000 and 5800 series rely on a Hollowtech bottom bracket with external bearings. As long as the bottom bracket is compatible with your frame, you can use a unit from either of the series.
And since the bottom brackets are identical, the cranks are interchangeable too. The only difference is that the R7000 doesn’t offer a 172.5mm crank, and the user has to choose between 160mm, 165mm, and 175mm lengths.
Conclusion: The cranks and bottom brackets from both series are compatible.
Since both systems use 11-speed cassettes, the hub doesn’t matter as long as it’s designed for road bikes and 11 speeds.
The cassettes are also interchangeable as long as the derailleur can operate with the unit of choice. As already mentioned, a short cage derailleur cannot climb a large (11-34) cassette.
Conclusion: The cassettes and hubs from both series are compatible.
Since both series are designed for 11-speeds, so are the chains and are therefore interchangeable. (Note: It will be necessary to re-adjust the chain length when switching chainrings and/or cassettes.)
Summary: What You Need To Know
- R7000 and 5800 are both 11-speed road groupsets. As such, they share a lot of similarities. The main advantage of R7000 is that it’s newer and implements more up-to-date technologies.
- The rear shift ratio of R7000 and 5800 rear derailleurs is the same. Therefore, you can use a derailleur from either series as long as it has the capacity to cover your cassette.
- The front derailleurs and shifters are also cross-compatible.
- The mechanical caliper brake levers are also cross-compatible.
- The bottom bracket, chain, cranks, and cassettes are cross-compatible.