component-ST-RX815

Shimano GRX supports disc brakes only and this makes sense considering the improved tyre clearance and better performance under rough conditions. Its ergonomics

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## Cable actuated disc brakes
Even though I strongly recommend you use the GRX hydraulic disc brakes, there are no doubt people wanting to run cable-actuated disc brakes due to financial reasons. In that case you will not be able to use the GRX levers. These levers support hydraulic disc brakes only. You *can* use any other Shimano Di2 Dual Control Lever though, like the [ST-6870](/component/ultegra-dual-control-lever-st-6870/), [ST-9070](/component/dura-ace-dual-control-lever-st-9070/), [ST-R8050](/component/ultegra-dual-control-lever-st-r8050/) or [ST-R9150](/component/dura-ace-dual-control-lever-st-r9150/)

The GRX ergonomics are excellent for gravel riding, but if you're looking for other *hydraulic disc* levers, have a look at the [Ultegra ST-R8070](/component/ultegra-hydraulic-disc-brake-lever-st-r8070/) and [Dura-Ace ST-R9170](/component/dura-ace-hydraulic-disc-brake-dual-control-lever-st-r9170/).

Introduced early in 2019, GRX is Shimano’s first Gravel group set. It delivers good performance both on the road and off the beaten path. GRX and Road share the same 'category as far as Di2 is concerned, meaning you can mix GRX derailleurs with Road Di2 derailleurs, but not with MTB derailleurs.

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Hydraulic Disc Brake Dual Control Lever

Brakes and shifters are pretty much essential when it comes to building a bike and Di2 bikes are no different. On a road or gravel bike you’ll probably want to install a Shimano Dual Control lever. 

If you’re building a mountain bike, have a look at the [MTB Style Shifting Switch installation guide](/mtb-style-shifter-sw-m8050-sw-m9050-installation-guide/).

This guide applies to all wired Di2 Dual Control levers. At the time of writing that is:

- [Ultegra ST-6770](/component/ultegra-10-speed-dual-control-lever-st-6770/)
- [Ultegra ST-6870](/component/ultegra-dual-control-lever-st-6870/)
- [Ultegra ST-R8050](/component/ultegra-dual-control-lever-st-r8050/) / [ST-R8070](/component/ultegra-hydraulic-disc-brake-lever-st-r8070/)
- [Ultegra ST-R8150](/component/ultegra-rim-brake-wired-dual-control-lever-st-r8150/)
- [DURA-ACE ST-9070](/component/dura-ace-dual-control-lever-st-9070/)
- [DURA-ACE ST-R9150](/component/dura-ace-dual-control-lever-st-r9150/) / [ST-R9170](/component/dura-ace-hydraulic-disc-brake-dual-control-lever-st-r9170/)
- [DURA-ACE ST-R9250](/component/dura-ace-rim-brake-wired-dual-control-lever-st-r9250/)
- [GRX ST-RX815](/component/grx-hydraulic-disc-brake-lever-st-rx815/)
- [ST-R785](/component/non-series-hydraulic-disc-brake-lever-st-r785/)

While there are subtle differences between all of these, they are also very much similar. I’ll ignore the obvious rim brake vs disc brake difference and show you the general process of installing a Di2 Road/GRX Dual Control lever. Also, I will not show you how to install hydraulic disc hoses or bleed the system. There are some links explaining this process at the bottom of the page.

## Tools required
- **2mm and 5mm Hex wrenches**. I use a Wera set ([Amazon](https://amzn.to/3zu60pU) / [Ebay](https://ebay.us/GJ5RZu))
- **Torque wrench (5-6Nm)**. I use a PRO Torque Wrench ([Amazon](https://amzn.to/2ULUGqv) / [Ebay](https://ebay.us/NUCe98))
- **Shimano TL-EW02**. [Di2 wire tool](/component/di2-cable-plug-tool-tl-ew02/).


## Slide the lever onto the handlebar
The very first step is to actually slide the lever onto the handlebar. In order to do this, you’ll have to loosen the lever clamp bolt. This bolt is hidden under the lever’s hood cover, so you’ll have to pull that forward to expose the bolt.

Note: if you’re installing a DURA-ACE lever then you may have to peel the cover back from the front of the lever. On most other models though, simply push the lever hood cover to the front.

![Install Di2 lever, push the hoods back](https://assets.bettershifting.com/install_lever_push_hood_back_95d4e49215.jpg)

Take your **5mm hex wrench** and loosen the bolt enough so that you can slide the lever over the handlebar to its somewhat final position. I say “*somewhat final*” because you’ll probably want to spend some time later aligning both levers and fine-tuning your hand position.

Also, if you’re installing hydraulic disc brake levers you may have to loosen and rotate them to properly bleed the system. In that case, it’s probably a good idea to set the final lever height and angle once you’ve bled the system.

Repeat the process for the other lever and proceed to the next section.

## Set the final lever height and angle
Now move the shift levers to a position that feels right to you. Most people want a smooth transition from handlebar to the lever, but everyone is different and has their own preferences.

Once you’ve decided on your lever position, let’s make sure the levers are aligned and are the same height.

You can do this using a long bar or a piece of string that you run along the levers. The string or bar should be parallel with the handlebar. I realise this may sound a bit cryptic, so this is what it looks like:

![Install Di2 lever set height using bar](https://assets.bettershifting.com/install_lever_bar_align_lever_height_dc40cf2a6b.jpg)

Or, using a piece of string (brake cable in this case):

![Install Di2 lever set height using brake wire](https://assets.bettershifting.com/install_lever_wire_align_lever_height_b198c1eb8b.jpg)

Satisfied with the lever position and height? Next stand over the bars and look down at the levers. They should be parallel to each other and the center of the bike.

## Di2 wire length and slack
With the levers set to their final position it’s time to connect the Di2 wires. I won’t go into detail on how to install your Junction A.. I have a pretty good [guide on installing the bar-end EW-RS910 junction](/bar-end-junction-ew-rs910-installation-guide/) and installing the [below-the-stem junction](/component/below-the-stem-junction-a-sm-ew90/) is pretty straightforward.

What *is* important though, is the wire length. If your wires are too short you won’t be able to connect the shift lever or run the risk of accidentally unplugging it. On the other hand, if the wire is too long you’ll have excess wire, but you can usually hide most of that in the handlebar or frame.

So.. if you’re in doubt, prefer a wire that is slightly too long rather than too short.

The general Shimano rule of thumb is this:

> Measure the length you need by running a piece of string along the handlebar. Then go the **next size up** and then **add 50mm**.

So if the measured length is 230mm, the next size up is 250mm and Shimano would recommend a 300mm wire.

## Connecting Di2 wires
With the correct length wires in hand, it's now time to install them. First run them along or through the handlebar, most likely from your Junction A to the shift lever. 

If you’re experiencing difficulty running the Di2 wires through the handlebar, give a routing tool a try (I use the [PRO Internal Routing Kit](/component/pro-internal-routing-tool/), but Park and Jagwire make them too).

At this point, it just comes down to plugging the wires in, but first read these quick tips that will no doubt make life easier for you:

- [The lever Di2 connection terminal can angle outward](#terminalcanangleoutward)
- [Some levers have dedicated sprint shifters ports](#somelevershavesprintshifterport)
- [Make sure there is some slack in the wires](#makesurethereisslackinwire)

### The Di2 connection terminal can angle outward {#terminalcanangleoutward}
You can actually plug the wires in by just pushing the lever hood back and then plugging the wire in. However, things get a lot easier when you push the hood back just a bit more, allowing the connection terminal to angle outward:

![Di2 lever terminal angle outwards](https://assets.bettershifting.com/install_levers_angle_connection_terminal_out_70ab960788.jpg)

### Some levers have a sprint shifter port {#somelevershavesprintshifterport}
All Di2 **rim** brake levers have **three ports** and almost all **hydraulic disc brake** levers have **two** e-tube ports (the exception is [ST-R785](/component/non-series-hydraulic-disc-brake-lever-st-r785/), which has just one port). 

The third port on the rim brake levers is a dedicated sprint shifter port. It can only be used to connect the [Di2 SW-R610 Sprint Shifter](/component/remote-sprint-shifter-sw-r610/) and **nothing else** will work in that port. Keep this in mind when connecting your wires, as this is an easy mistake to make.

![Dedicated sprint shifter port](https://assets.bettershifting.com/install_levers_sprint_shifter_port_a6b1063547.jpg)

While the sprint shifter port looks different - it has a notch for the ‘fin’ on the sprint shifter wire - there is nothing stopping you from inserting a regular wire into the port. The wire will go in, but it won’t work - this sprint shift port doesn’t have the required logic circuitry to connect anything but simple switches.

### Make sure there is some slack in the wires {#makesurethereisslackinwire}
This is perhaps the most important thing when connecting Di2 shift levers. Make sure there is some slack in the wire. Having a little ‘U’ of excess wire near the shift lever is highly recommended.

![Di2 wire installed excess wire slack](https://assets.bettershifting.com/install_levers_excess_wire_slack_15e4ec5f1b.jpg)

This will prevent you from accidentally disconnecting or breaking the Di2 wire when the lever moves or simply by grabbing and twisting the bar tape. Trust me, it happens.
And yeah.. a lever does not move on its own.. but crashes do happen. 

Even when your bike falls over or when you pull the lever hard enough, this can happen. If there is no slack in the wire at all then even the slightest of movements can be enough to loosen the wire.

## Tweak your brake lever reach
You’re almost done, honest. Some people skip this step, but for those of us with small hands it is good to know that you can easily adjust the lever reach - move the brake lever towards or away from the handlebar.

The process is similar for rim and hydraulic disc levers, with subtle differences. In both cases, you adjust the lever reach using the so-called reach adjustment screw. 

On the rim brake levers you will find this on top of the lever body itself:

![Rim lever reach adjustment](https://assets.bettershifting.com/install_lever_rim_reach_adjustment_7b1c5a9815.png)

The hydraulic disc brake levers feature an adjustment screw on the lever:

![Hydraulic disc lever reach adjustment](https://assets.bettershifting.com/install_lever_hydraulic_disc_reach_adjustment_0fbf6b3a44.png)

In both cases you need a **2mm hex wrench** to adjust the screw. Set up the reach so that you can easily use the brakes and then that’s it - you’re all done!

Except when you’re installing a hydraulic disc lever…. sorry. One final thing you can do is to adjust the free stroke - the amount of “empty” pull before the brakes engage. Once again, use a **2mm hex wrench** to adjust the free stroke as you see fit.

![Hydraulic disc free stroke adjustment](https://assets.bettershifting.com/install_lever_hydraulic_disc_free_stroke_adjustment_1980334506.png)

This is what Shimano says on the free stroke adjustment:

- Stop loosening the free stroke adjustment screw when the free stroke stops increasing. (loosening the free stroke adjustment screw excessively may cause the screw to be removed from the bracket unit) 
- Do not forcibly tighten the free stroke adjustment screw. Otherwise, the adjustment screw may be damaged. 
- Do not remove the washer from the free stroke adjustment screw.
- Position the free stroke adjustment screw so that it does not interfere with the bracket cover.

## Brake wire or hydraulic hose
That concludes this Di2 wired lever installation guide. As I said right at the start, I’m intentionally leaving out the process of installing the brake wire or hydraulic hose. 

This could be an entire page on its own, but fortunately you can also figure out how to do this by [reading the Shimano Dealer Manual](/learn-how-to-use-the-shimano-documentation/) or the [Park Tool guide](https://www.parktool.com/blog/repair-help/brake-bleeding-for-shimano-drop-bar-hydraulic-brakes-using-the-bkm-1).


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Learn how to install Di2 drop bar levers commonly used on Di2 road bikes or Di2 gravel bikes. This walks you through the process and lists useful tips.

Installation guide: Di2 wired shift levers

Do you have smaller hands than most and do you find the brake levers on your Shimano bike a bit hard to operate? Or are your hands relatively large? 

Don't worry, you can easily change the lever reach and bring the brake levers closer - or move them further away.

You can change your lever reach on all Di2 levers, and it generally works the same for non-Di2 Shimano levers.  All you need is a **2mm hex key**. 

Note that the *reach* is sometimes also referred to as *lever stroke*, especially in older Shimano documentation.

## Change rim brake Di2 lever reach
Since the process is slightly different for rim brake levers and hydraulic disc brake levers, I've split this page up into two small sections. This section describes how to change the reach on the rim brake [ST-6770](/component/ultegra-10-speed-dual-control-lever-st-6770/), [ST-6870](/component/ultegra-dual-control-lever-st-6870/), [ST-R8050](/component/ultegra-dual-control-lever-st-r8050/), [ST-R8150](/component/ultegra-rim-brake-wired-dual-control-lever-st-r8150/), [ST-9070](/component/dura-ace-dual-control-lever-st-9070/), [ST-R9150](/component/dura-ace-dual-control-lever-st-r9150/), and [ST-R9250](/component/dura-ace-rim-brake-wired-dual-control-lever-st-r9250/) levers.

Changing the lever reach (or stroke) on the rim brake levers is easy enough. The first thing you do is pull back the cover to expose the adjustment bolt.

![Pull hood cover to back](https://assets.bettershifting.com/pull_back_from_front_f6bd95de5c.png)

Next, take your **2mm** hex wrench. 

![ST-6870 adjusting](https://assets.bettershifting.com/st_6870_adjust_reach_7ba57f32d9.jpg)

Turn **left** or **counterclockwise** to move the lever outward, or **increase** the reach. This will effectively move the lever further away from the handlebar.

Turn **right** or **clockwise** to move the lever in, or **decrease** the reach. This moves the lever closer, making it easier to grab.

On my Ultegra 6870 lever, the full range of motion (adjustability?) looks like this:

![ST-6870 reach adjustment range](https://assets.bettershifting.com/st_6870_reach_range_ec3b2eee0b.gif)

## Change disc brake Di2 lever reach
This section applies to the hydraulic disc Di2 shift levers: [ST-R785](/component/non-series-hydraulic-disc-brake-lever-st-r785/), [ST-R8070](/component/ultegra-hydraulic-disc-brake-lever-st-r8070/), [ST-R8170](/component/ultegra-disc-brake-wireless-dual-control-lever-st-r8170/), [ST-R9170](/component/dura-ace-hydraulic-disc-brake-dual-control-lever-st-r9170/), [ST-R9270](/component/dura-ace-disc-brake-wireless-dual-control-lever-st-r9270/), and the GRX [ST-RX815](/component/grx-hydraulic-disc-brake-lever-st-rx815/). 

Shimano's hydraulic disc levers have both a *reach* and a *free stroke* adjustment. 

Changing the *reach* will affect how close the brake lever is to the handlebar, while the *free stroke* changes the amount of travel before the brake pads hit the rotor. 

This page is on changing the reach only, but there are plenty of videos on setting up the free stroke on [YouTube](https://youtube.com). Note that if you change the free stroke, that'll also change the initial lever position - and you may need to change your reach afterward as well.

This video by [Rides of Japan](https://www.youtube.com/@ridesofjapan) explains it well:

<YouTube videoId="9TkudgYe0EY" />

### Change reach on R8070, R9170, R7170, R8170, and R9270
Setting up the shifter reach on [ST-R8070](/component/ultegra-hydraulic-disc-brake-lever-st-r8070/), [ST-R8170](/component/ultegra-disc-brake-wireless-dual-control-lever-st-r8170/), [ST-R9170](/component/dura-ace-hydraulic-disc-brake-dual-control-lever-st-r9170/), and [ST-R9270](/component/dura-ace-disc-brake-wireless-dual-control-lever-st-r9270/) is easy - you don't even have to move the lever cover.

The adjustment bolt for the **reach** is on the inside of the lever itself, as shown in the **left** half of this image:

![ST-R8070 reach adjust photo](https://assets.bettershifting.com/st_r8070_reach_adjust_d1ebcb28b1.jpg)
(the bolt shown on the right is the **free stroke** adjustment bolt)  
  
Turning the bolt clockwise increases the lever reach, while turning it counterclockwise decreases the reach. 

![ST-R8070 reach adjustability](https://assets.bettershifting.com/st_r8070_adjust_range_ee7dfb120c.gif)

### Lever reach on ST-R785 and ST-RX815
In order to change the reach on these levers, you'll have to pull back the hood cover as shown below.

![Pull hood cover to back](https://assets.bettershifting.com/pull_back_from_front_f6bd95de5c.png)

Next, locate the reach adjustment bolt. On ST-RX815 it is located on top of the lever:

![ST-RX815 lever reach bolt](https://assets.bettershifting.com/st_rx815_lever_reach_bolt_81bc618914.png)

Turn clockwise to decrease lever reach. Turn anticlockwise to increase the reach, or move the lever away from the handlebar. Use a **2mm** hex wrench.

The ST-R785 lever reach adjustment bolt works the same as the others - turn clockwise to increase the reach, and turn counterclockwise to decrease it. Note that you'll have to use a flat-head screwdriver.

![ST-R785 adjust bolt image](https://assets.bettershifting.com/st_r785_reach_adjust_screw_92b60346a7.png)

## Question, comments, suggestions
That's it! You should now be able to set up the reach as you like. 

Are things unclear, or are you missing something? Please let me know! You can [send me a message](/contact/), or leave a comment below.

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Do you have small hands? Or extra large hands? Read this page to figure out how to change your Shimano Di2 shift lever (or shifter) reach.

Hydraulic Disc Brake Dual Control Lever

Cable actuated disc brakes

Details & Specifications

Shopping links

More images