Posted at: Mar. 16, 2021
Shimano's GRX series of gravel components can be used in combination with other road bike components, including tips on how to mix and match.
Table of contents
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Shimano’s GRX gravel components are derived from road bikes, so they are highly compatible with road bike parts.
Specifically, the drivetrain is basically officially compatible with the last two generations of components with the same number of steps. Chains and sprockets are shared with road components as long as they have the same number of steps.
When mixing GRX and road components, it is necessary to combine parts with the same number of speeds (gears) as a prerequisite.
The GRX is available in the following three lineups.
Compatible with the current TIAGRA and above componentry for road bikes.
Specific compatibility is as follows
| Model | Model number | Speed | Compatible road bike components |
|---|---|---|---|
| GRX Di2 | RX-815 | 11s | DURA-ACE R9050s, 9070s ULTEGRA R8050s |
| GRX 11 | RX-810, RX-600 | 11s | DURA-ACE R9000 series, 9000 series ULTEGRA R8000 series, 6800 series 105 R7000 series, 5800 series |
| GRX 10 | RX-400 | 10s | ULTEGRA 6700s 105 5700s TIAGRA 4700s, 4600s |
Shimano’s 10-speed components are not compatible with TIAGRA, so you need to be careful when combining GRX and TIAGRA parts.
Be careful about compatibility when choosing Shimano TIAGRA components
TIAGRA componentry is Shimano's top entry grade for road bikes. TIAGRA is easy to choose as a 10-speed grade, one step down from the current higher grade of 11-speed, but you need to be careful when choosing components for compatibility.
Of course, electric (Di2) and mechanical components cannot be combined even at the same speed.
Shimano’s components for road bikes are designed for cross-ratio sprockets, so the maximum number of teeth and capacity of the rear derailleur are smaller than those of components for MTB.
In recent years, GS (middle cage) models are also available in the rear derailleur lineup, but in the case of gravel components, the sprocket may be chosen to be a wide ratio product such as 11-42T for MTB, in which case the maximum tooth count may exceed 40, which cannot be handled even by GS (middle cage) models for road use.
When using a wide-ratio sprocket with a low maximum exceeding 36, choose a GRX rear derailleur straightforwardly.
One more thing to note is that all GRX series STI levers are “hydraulic disc brake only”.
There are two types of disc brakes for road bikes, mechanical and hydraulic, but the mechanical type, which physically closes the caliper by pulling the wire, and the hydraulic type, which closes the caliper by the difference in pressure of the oil filled in the hose, have different structures and cannot be used together.
In addition, Shimano’s components for road use do not have hydraulic rim brakes, so rim brakes cannot be used either.
If you want to convert your road bike to disc brakes, you will need to prepare a disc frame as well as wheels.
Disc brake-equipped road bikes have been on the rise in the past few years. "For those who want to try out disc brakes but don't want to buy a new bike, we've put together a list of the parts you'll need to buy disc brakes and the points to keep in mind when buying.
If you are currently riding a rim-brake road bike and are considering converting to gravel using GRX components, you can save money by using STI levers that are compatible with GRX for road use instead of GRX.
Unlike ULTEGRA and 105, GRX 10-speed models are not compatible with DURA-ACE.
| Model | Model number | Speed | Compatible road bike components |
|---|---|---|---|
| GRX Di2 | RX-815 | 11s | DURA-ACE R9050 series, 9070 series |
| GRX 11 | RX-810, RX-600 | 11s | DURA-ACE R9000 series |
Shimano’s GRX for gravel bikes and ULTEGRA for road bikes are compatible with ULTEGRA 6700 and above, and ULTEGRA is the only component that is compatible with all GRX models, including GRX electric shifting models, because ULTEGRA has Di2 models.
| Model | Model number | Speed | Compatible road bike components |
|---|---|---|---|
| GRX Di2 | RX-815 | 11s | ULTEGRA, R8050 series |
| GRX 11 | RX-810, RX-600 | 11s | ULTEGRA, R8000 series, 6800 series |
| GRX 11 | RX-810, RX-600 | 11s | ULTEGRA, R8000 series, 6800 series |
Shimano’s GRX for gravel and 105 for road bikes are compatible with 105, 5700 and above; as of February 2021, there are no 105 models with Di2 electric shifting, so GRX Di2 models are not compatible.
| Model | Model number | Speed | Compatible road bike components |
|---|---|---|---|
| GRX 11 | RX-810, RX-600 | 11s | 105, R7000 Series, 5800 Series |
| GRX 10 | RX-400 | 10s | 105, 5700 series |
The only compatible combinations of Shimano’s GRX for gravel and TIAGRA for road bikes are TIAGRA/4700 series and 4600 series and GRX 10.
| Model | Model number | Speed | Compatible road bike components |
|---|---|---|---|
| GRX 10 | RX-400 | 10s | TIAGRA・4700s、4600s |
Shimano’s GRX for gravel is basically compatible with road bike components, but please note the following points
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