Set up Front Derailleur limits (FD-RX815, FD-R9150, FD-R8050)
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:
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 for information on how to do that.
Adjusting the top adjustment bolt
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.
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.
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.
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).
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.
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.
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.
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.
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 any time!