component-FD-RX815-F

The Shimano GRX RX815 Di2 gravel front derailleur was developed to handle the different GRX chain line (+2.5mm outwards) perfectly. It is meant to be used with 

di2-dealer-manual-grx-rx815

GRX RX815 Dealer Manual

manual-di2-front-derailleur

Di2 Front Derailleur User Manual

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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Front Derailleur

This guide applies to 11-speed front road and gravel derailleurs that have one adjustment bolt (or limit screw). 

You set up the top (high) limit for these derailleurs using the adjustment bolt, and set up the low limit electronically. The latest generation 11-speed derailleurs are one-adjustment-bolt derailleurs:

- [GRX FD-RX815](/component/grx-front-derailleur-fd-rx815-f/)
- [DURA-ACE FD-R9150](/component/dura-ace-front-derailleur-fd-r9150-f/)
- [Ultegra FD-R8050](/component/ultegra-front-derailleur-fd-r8050-f/)

Before your start, make sure you have correctly set up your front derailleur height, angle, and support bolt. Have a look at the [front derailleur installation guide](/grx-fd-rx815-ultegra-fd-r8050-dura-ace-fd-r9150-di2-front-derailleur-installation-guide/) for information on how to do that.

## Adjusting the top adjustment bolt
![One bolt FD Adjustment and Support bolts](https://assets.bettershifting.com/one_bolt_limit_setup_GRX_ultegra_dura_ace_fd_bolts_51b07dc9d1.png)

These 11-speed front derailleurs have only one adjustment bolt, but just like all other Di2 front derailleurs they also have the support bolt. Make sure you adjust the correct bolt. 

You will need a **size 2 hex wrench** to set the top adjustment bolt.

![FD large/small adjustment](https://assets.bettershifting.com/one_bolt_limit_setup_fd_largest_rd_smallest_7e8125f0e4.png)

The first step is to shift the front derailleur to the **large chainring** and the rear derailleur to the **smallest sprocket**.

Next, turn the top adjustment bolt to set the correct clearance between the chain and chain guide outer plate. You’re looking for **0.5 – 1 mm** of clearance.

![FD support bolt](https://assets.bettershifting.com/one_bolt_limit_setup_GRX_ultegra_dura_ace_fd_bolt_directions_d8bba44ee7.png)

## Set the low limit
There may not be a low adjustment bolt, but that doesn’t mean you do not need to set it up. To start, shift the front derailleur to the **small chainring** and the rear derailleur to the **largest sprocket**.

![FD Adjustment mode button](https://assets.bettershifting.com/one_bolt_limit_setup_GRX_ultegra_dura_ace_fd_low_adjustment_634dc4fc4c.png)

Now press and hold the button on your junction box A until the LED next to it lights up red. This should take about **2 - 5 seconds**.

You will now enter adjustment mode. Be sure to release the button on time – if you keep it pressed the rear derailleur protection reset will trigger.

The final step is to set the correct clearance between the chain and the chain guide **inner plate**. This time you’re looking for about **0.15 to 0.5 mm** of clearance (Shimano say 0 – 0.5 mm, but anything near 0 mm would likely cause chain rub).

![FD one-bolt adjustment](https://assets.bettershifting.com/one_bolt_limit_setup_GRX_ultegra_dura_ace_adjust_buttons_direction_1024x403_7e38724392.png)

All three of these derailleurs can move 18 steps inward and 18 steps outward from the initial position (37 steps total). It can be easy to lose track of the current position, but if you find that it doesn’t move when you press a button you’ve probably gone too far. You can get the current adjustment value by [connecting the bike to a windows computer](/how-to-connect-your-di2-system-to-your-windows-computer/).

Note that when you’re in this adjustment mode the chain guide will overrun slightly and then move back in an exaggerated manner, so that you can check the adjustment direction. When checking the positions of the chain guide and the chain, perform the check after the front derailleur has moved back and come to a stop.

Press and hold the button on your junction A to leave adjustment mode. Now shift the front and rear derailleurs through all gears and make sure chain rub does not occur in any gear. If it does, go back into adjustment mode and tweak the chain clearance.

## Set the high/top limit
After setting the Top limit screw and electronically setting the Low limit it is time to finish setting up the front derailleur by setting the **Top limit electronically**. This time however, you’ll have to set the clearance between **0 – 0.5 mm**.

![One bolt front derailleur, shift to the right gear](https://assets.bettershifting.com/one_bolt_limit_setup_GRX_ultegra_dura_ace_fd_top_electrical_adjustment_3a321b2381.png)

To do this shift to the **largest chainring** and **largest sprocket**, and then press and hold the button again to enter adjustment mode. Set the clearance between the chain and front derailleur chain guide **inner plate** to **0 - 0.5 mm**.

![One bolt front derailleur, tweak the front derailleur top electrical limit.](https://assets.bettershifting.com/one_bolt_limit_setup_GRX_ultegra_dura_ace_fd_top_electrical_adjustment2_9a2025b8c9.png)

Check to make sure there is no rubbing, and then exit adjustment mode.

Setting the limit screw first and then setting the top limit electronically will allow the front derailleur to overshift, to then return to its correct position as set using the electronic limit.

## All set!
That's it - your derailleur should now be working just fine, without any chain rub. Take the bike for a ride, and tweak the settings if necessary. 

Is the front derailleur giving you a hard time? Feel free to [send me a message](/contact/) any time!

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Read how to set up your two-adjustment-bolt Di2 Front Derailleur (Ultegra FD-R8050, DURA-ACE FD-R9150, GRX FD-RX815)

Set up Front Derailleur limits (FD-RX815, FD-R9150, FD-R8050)

Installing the [GRX FD-RX815](/component/grx-front-derailleur-fd-rx815-f/), [FD-R8050](/component/ultegra-front-derailleur-fd-r8050-f/) and [FD-R9150](/component/dura-ace-front-derailleur-fd-r9150-f/) front derailleurs is not hard, but Shimano recommend you do it in two stages. First you attach the front derailleur and the electric wire, then install the Crankset and make the final height adjustments to set up the front derailleur correctly. The tools needed for installation are:

- [Shimano TL-EW02 cable plug tool](/component/di2-cable-plug-tool-tl-ew02/)
- Size 2 hex wrench
- Size 5 hex wrench

## Attach the derailleur to the frame
The current generation [FD-RX815](/component/grx-front-derailleur-fd-rx815-f/), [FD-R8050](/component/ultegra-front-derailleur-fd-r8050-f/) and [FD-R9150](/component/dura-ace-front-derailleur-fd-r9150-f/) front derailleurs are available in braze-on version only. This doesn’t mean that you cannot use it if your frame does not have a braze-on mount, but you’d need the [clamp-on adapter](/component/front-derailleur-road-clamp-band-adapter-sm-ad91). Follow the steps corresponding to your mounting option.

### When there is a mounting boss on the frame
Use your **size 5 hex wrench** to loosely screw in the mounting bolt and attach the derailleur to the frame. Do *not *tighten it fully yet.

These derailleurs have a tiny bolt that goes through the derailleur and comes out the back. You’ll later tighten this bolt to sit flush against the frame, giving the derailleur something to push against when shifting. 

Now check where the derailleur’s support bolt hits the frame,  and stick the **backup plate** on the frame by peeling off the liner on the back. The **backup plate** is the small metal plate you got with the front derailleur - it’s there to prevent damage to the frame itself.

Note that if the support bolt touches the frame’s mounting boss itself, you may not need the **backup plate**. I haven’t used this plate [on my Cinelli](/build-log-cinelli-veltrix-disc-di2/), for example. 

The support bolt should touch the side of the backup plate without the tape. Tighten the bolt until it touches the backup plate.

![FD backup plate](https://assets.bettershifting.com/FD_RX_8_F_backup_plate_ffb50b3d29.png)

### When there is no mounting boss on the frame
If the frame you’re using does not have a mounting boss you will need a Front-derailleur band adapter. While you can probably get away with using any band adapter, I recommend using the one Shimano make, the [SM-AD91 band adapter](/component/front-derailleur-road-clamp-band-adapter-sm-ad91). 

Install the band adapter to the front derailleur using a size 5 hex wrench and the provided bolt. You do not have to install the backup plate, since you'll tighten the support bolt to sit flush against the clamp band. It won't damage your expensive frame.

Now tighten the derailleur’s support bolt using a **size 2 hex wrench** until it only just touches the backup plate.

Remove the clamp bolt from the clamp band, attach the band to your frame and insert and tighten the clamp bolt. Do *not* tighten it fully yet, as we haven’t checked the height of the front derailleur yet. 

![FD clamp adapter](https://assets.bettershifting.com/FD_RX_8_F_band_adapter_4fda7d040f.png)

## Install the Electric Wire
Now that the derailleur is attached to the frame, install the [Electric Wire](/component/di2-electric-wire-ew-sd50). If you haven’t run the wire through the frame yet, now is the time. Ideally you do this before installing the Crankset, allowing for easy access to the front derailleur.

These front derailleurs both come with a wire cover and we recommend you use it. Install the electric wire to the plug cover, and then push the wire and plug cover into the port of the derailleur.

You will need to use enough force and push until you feel it click into place. If you do not feel or hear it click, ***the wire is not attached properly and will come loose***.

![FD attach wire](https://assets.bettershifting.com/FD_RX_8_F_attach_wire_dcbade0147.png)

There are two holes in the wire cover, allowing you to use the [Plug Installation Tool TL-EW02](/component/di2-cable-plug-tool-tl-ew02/) to help push the connector into place. The tool can also be used on the wire plug itself.

## Set the front derailleur height and angle
Make sure the crankset is installed so that you can secure the front derailleur to the frame at the right height and angle. First we’ll adjust the derailleur height.

Loosen the mounting bolt and move the front derailleur vertically until there is about **1-3 mm of clearance** between the chain guide outer plate and the tip of the teeth of the largest chainring.

![Set FD height](https://assets.bettershifting.com/FD_RX_8_F_derailleur_height_349bc05a8f.png)

To set the angle of the Front Derailleur, rotate it so that the flat surface of the chain guide outer plate is directly above the largest chainring and the rear edge of the chain guide is inwards by **0.5 to 1 mm** compared to the front edge.

**Note**: if the derailleur appears to be too close to the frame, screw the high limit screw in a bit more to allow the derailleur to move further from the frame.

![FD set correct angle](https://assets.bettershifting.com/FD_RX_8_F_set_angle_1024x752_f58f6b6e4e.png)

Now let’s straighten up the Front Derailleur so that the chain guide outer plates are in line with the chainring. Use a **size 2 hex wrench** to adjust the support bolt.

Make sure that the flat portion of the chain guide outer plate is aligned with the surface of the largest chainring. If the support bolt does not touch the backup plate, move the backup plate so that it does.

![FD support bolt](https://assets.bettershifting.com/FD_RX_8_F_support_bolt_straighten_1024x609_b169a2d49b.png)

## Almost done!
That concludes the installation of your front derailleur. It should now be properly attached to your frame. The only thing that’s left to do is set the [Top Adjustment bolt and the low/high limits](/set-up-front-derailleur-limit-screw-adjustment-bolt-one-bolt-derailleurs/).

This can only be done once all components have been installed. Read about [setting the Top Adjustment bolt on this page](/set-up-front-derailleur-limit-screw-adjustment-bolt-one-bolt-derailleurs/).

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Bought a new Di2 derailleur or have to replace your old one? Read FD-rx815 / FD-R8150 / FD-R9150 Di2 Front Derailleur installation instructions here.

Front Derailleur

Details & Specifications

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