Go Back  Bike Forums > Bike Forums > Road Cycling
Reload this Page >

DI2 junction box Under the Stem vs bar end

Notices
Road Cycling ďIt is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.Ē -- Ernest Hemingway

DI2 junction box Under the Stem vs bar end

Old 06-20-20, 05:11 PM
  #1  
Captain_Canada
Member
Thread Starter
 
Join Date: Oct 2017
Posts: 31
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 22 Post(s)
Liked 1 Time in 1 Post
DI2 junction box Under the Stem vs bar end

Is one better than the other? I don't really like the looks of the under the stem box/rubber band.

Also, with the bar end box available, why do some manufacturers go through the trouble of bringing the box into the frame? Danger of the bar end getting knocked in a crash?

I've never had electronic shifting but am thinking of my next bike.
Captain_Canada is offline  
Likes For Captain_Canada:
Old 06-20-20, 06:07 PM
  #2  
MidTNBrad
Senior Member
 
Join Date: Mar 2017
Location: Franklin, TN
Posts: 274

Bikes: 2016 Cervelo R3 & 1999 Litespeed Tuscany

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 103 Post(s)
Liked 39 Times in 26 Posts
I have the 6800 version of Di2 (previous version) and have the external junction box because the bar end wasn't available. I'd go with the bar end if I were purchasing now.

I got one of these to clean up my stem.
Di2 mount
MidTNBrad is offline  
Likes For MidTNBrad:
Old 06-20-20, 06:40 PM
  #3  
eflayer
Senior Member
 
Join Date: Oct 2008
Posts: 79
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 28 Post(s)
Likes: 0
Liked 14 Times in 11 Posts
the evolution of di2

2019 Roubaix is the bar end. 2020 Roubaix is integrated into the molding of the frame and now in the downtube. under the stem is first phase and the least aesthetically please but maybe the easiest to deal with if any wrenching is needed.

Last edited by eflayer; 06-20-20 at 07:42 PM.
eflayer is offline  
Old 06-20-20, 07:35 PM
  #4  
Steve B.
Senior Member
 
Join Date: Jul 2007
Location: South shore, L.I., NY
Posts: 4,402

Bikes: Flyxii FR322, Cannondale Topstone, Miyata City Liner, Specialized Chisel

Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1623 Post(s)
Liked 330 Times in 235 Posts
Originally Posted by Captain_Canada View Post
Is one better than the other? I don't really like the looks of the under the stem box/rubber band.

Also, with the bar end box available, why do some manufacturers go through the trouble of bringing the box into the frame? Danger of the bar end getting knocked in a crash?

I've never had electronic shifting but am thinking of my next bike.
Putting the A Junction into the bar end is reasonably out of the way, except when I think how many times Iíve knocked off a bar end cap. As well the h-bar needs holes to allow cables to route to the downtube, so handlebar purpose designed.
Steve B. is offline  
Old 06-21-20, 03:09 AM
  #5  
Falchoon
Senior Member
 
Falchoon's Avatar
 
Join Date: Oct 2002
Location: Oz
Posts: 979
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
Stem mounting is a lot cheaper. Bar end is more aesthetically pleasing. If I had a choice and they both cost the same then I would go for bar end.
Falchoon is offline  
Likes For Falchoon:
Old 06-21-20, 05:13 AM
  #6  
alcjphil
Senior Member
 
alcjphil's Avatar
 
Join Date: Jun 2002
Location: Montreal, Quebec
Posts: 3,773
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 919 Post(s)
Liked 272 Times in 177 Posts
Originally Posted by Captain_Canada View Post

I've never had electronic shifting but am thinking of my next bike.
If this were my case I would look for bikes that had the box located in the frame
alcjphil is offline  
Old 06-21-20, 10:29 AM
  #7  
popeye
Senior Member
 
Join Date: Nov 2004
Location: Newport Beach, CA
Posts: 1,557

Bikes: S works Tarmac, Felt TK2 track

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 178 Post(s)
Likes: 0
Liked 36 Times in 26 Posts
I run bar end but stem mount is much easier if you have to trouble shoot.
popeye is online now  
Old 06-21-20, 01:36 PM
  #8  
NoWhammies
Senior Member
 
NoWhammies's Avatar
 
Join Date: Jul 2017
Location: Vancouver, BC
Posts: 1,324

Bikes: Argon 18 Gallium, BH G7, Rocky Mountain Instinct C70

Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 570 Post(s)
Liked 163 Times in 104 Posts
If I had the choice I'd go with the bar end. Just looks nicer.
NoWhammies is offline  
Old 06-21-20, 04:04 PM
  #9  
Noctilux.95
Senior Member
 
Join Date: Sep 2014
Location: Southern California
Posts: 566

Bikes: Bianchi Oltre XR4 Celeste, De Rosa SK Pininfarina, Giant TCR SL, Giant Revolt Advanced Revolt 0 Gravel Bike, Trek Madone SLR, Cervelo R5 Disk

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 361 Post(s)
Liked 90 Times in 53 Posts
Bar end junction boxes exist due to the nastiness of the under the stem version.
Noctilux.95 is offline  
Likes For Noctilux.95:
Old 06-21-20, 05:05 PM
  #10  
Seattle Forrest
Senior Member
 
Seattle Forrest's Avatar
 
Join Date: Mar 2010
Location: Seattle, WA
Posts: 21,206
Mentioned: 67 Post(s)
Tagged: 0 Thread(s)
Quoted: 12035 Post(s)
Liked 3,374 Times in 1,884 Posts
How much does it cost to change over? Or is that only possible on newer versions?

I actually like the junction box under the stem. Di2 has been out for a long time, it used to always be under the stem ... I've seen so many nicer bikes than mine and many of them had that tell tale band holding the junction box in place. Feels like I've arrived or something.

But everything is set up nicely, and I bet that extra stuff costs me a few watts. It's not like I'm going to be getting many more as I age. Need every advantage I can get until the day I need an eBike to crash Strava KOMs.
Seattle Forrest is offline  
Old 06-21-20, 05:11 PM
  #11  
Steve B.
Senior Member
 
Join Date: Jul 2007
Location: South shore, L.I., NY
Posts: 4,402

Bikes: Flyxii FR322, Cannondale Topstone, Miyata City Liner, Specialized Chisel

Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1623 Post(s)
Liked 330 Times in 235 Posts
Originally Posted by Noctilux.95 View Post
Bar end junction boxes exist due to the nastiness of the under the stem version.
Never heard it referred to that way. ďNasty ?Ē. I know some folks donít like it as itís not a clean look. On some stems the band is noticeable and I guess that bothers people, but there are mounts that replace a few stem spacers, so cleans that part up. I have no issue as my bar is cluttered with a front light and my Garmin mount, so the A Junction is hardly noticed. If I didnít have a Garmin which shows me what gears Iím in, I would use the XT stem display.

But everybody has things they like or not.
Steve B. is offline  
Old 06-21-20, 07:04 PM
  #12  
rm -rf
don't try this at home.
 
rm -rf's Avatar
 
Join Date: Jan 2006
Location: N. KY
Posts: 5,185
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 672 Post(s)
Liked 55 Times in 44 Posts
Originally Posted by eflayer View Post
2019 Roubaix is the bar end. 2020 Roubaix is integrated into the molding of the frame and now in the downtube. under the stem is first phase and the least aesthetically please but maybe the easiest to deal with if any wrenching is needed.
I wondered how that worked, mounted into the frame. This looks practical, with all the junction wires in the frame and it's easily serviceable with removing one screw.



You can easily see the status lights while riding.
I do check the charge level on my 6800 under stem box. Just hold a shift button for more than a second and the box shows four levels of charge: green: 100-50%, blinking green: 50-25%, red:25% to minimal, blinking red: almost out.

I recharge soon after it shows blinking green. No need to let it run down farther. I just installed a replacement seatpost battery, after 5 1/2 years. The old one still worked, but it had to be recharged quite often.

Di2 was stupidly expensive back in Sept 2014, when I got the new bike. But it's been worth it, I really like the instant, drama free shifting. And the shifters and derailleurs are working like new. No noticeable wear in the derailleur pivots and it still shifts perfectly.

Last edited by rm -rf; 06-21-20 at 07:13 PM.
rm -rf is offline  
Likes For rm -rf:
Old 06-21-20, 11:37 PM
  #13  
bahula03
Senior Member
 
Join Date: Sep 2012
Posts: 270
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 16 Post(s)
Liked 25 Times in 12 Posts
The only real function difference between the SM-EW90A/B (under stem) and EW-RS910 (bar end/frame) is the number of ports, 3 or 5 for the SM-EW90 and 2 for EW-RS910, which only matters if you're adding accessories like sprint shifters or the climbing shifter...and don't have open ports on your levers.

Like others have mentioned, the EW-RS910 requires bars that have holes to route the wires, so you're constrained by that for upgrades/different sizes. Some
manufacturers will use the EW-RS910 and route the wires through both the bars and stem, which means having to find both components that are compatible. None of it's a big deal really, just preference on what it looks like, supporting components, and how easy/difficult it is to install.
bahula03 is offline  
Likes For bahula03:
Old 06-22-20, 07:25 PM
  #14  
jmess
Senior Member
 
jmess's Avatar
 
Join Date: Sep 2006
Location: PDX
Posts: 332
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 16 Post(s)
Liked 3 Times in 3 Posts
Something Different

I really like my the SC-MT800 System Display installed on my Bianchi XR4. The display has 3 Di2 ports and clamps to my handles bars.You can get one from Universal Cycles for $90. It works perfectly with the Road Di2 components. The display comes on every time you shift or touch the mode button. I have the display timer set to 30 seconds ( via e-tube-project configuration). I was having problems with my Di2 battery being run down by a Shimano Di2 inline Bluetooth module, it wasn't shutting off at times. The MT800 connects to my phone or Garmin 1030 with no problems. Firmware updates are easy via e-tube-project.
The SC-MT800 System Display is the brains of Shimano's XT Di2 electronic mountain groupset, allowing you to view data, control settings, and connect to the E-Tube Project application to customize your shifting preferences. Bluetooth and ANT+ enabled, the MT800 system display wirelessly connects to smart devices and cycling computers for seamless operation and control anywhere you go.
Details:
  • Displays system status of: battery level, gear position, shift mode and FOX iRD suspension position
  • Toggle audible shift notification chimes
  • Toggle between three Shimano Synchronized Shift modes available (S1/S2/Manual)
  • Digitally adjust front and rear derailleurs and provide numerical adjustment indicator
  • Wireless ANT / Bluetooth communication for customization and data utilization in the field with a smartphone, tablet, and other mobile electronics
  • Battery charging port
  • 3 E-Tube ports
  • D-Fly compatible
jmess is offline  
Old 06-22-20, 08:14 PM
  #15  
Chi_Z
Senior Member
 
Chi_Z's Avatar
 
Join Date: Dec 2013
Posts: 401

Bikes: Niner RLT 9 RDO

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 215 Post(s)
Liked 33 Times in 26 Posts
bar end is the way to go, but if you have older handle bar you have to drill out a hole
Chi_Z is offline  
Likes For Chi_Z:
Old 06-23-20, 02:18 AM
  #16  
TerryDi2C
Di2 fanatic
 
TerryDi2C's Avatar
 
Join Date: Aug 2019
Location: The Netherlands
Posts: 50
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Liked 12 Times in 10 Posts
Originally Posted by jmess View Post
I really like my the SC-MT800 System Display installed on my Bianchi XR4. The display has 3 Di2 ports and clamps to my handles bars.You can get one from Universal Cycles for $90. It works perfectly with the Road Di2 components. The display comes on every time you shift or touch the mode button. I have the display timer set to 30 seconds ( via e-tube-project configuration). I was having problems with my Di2 battery being run down by a Shimano Di2 inline Bluetooth module, it wasn't shutting off at times. The MT800 connects to my phone or Garmin 1030 with no problems. Firmware updates are easy via e-tube-project.
The SC-MT800 System Display is the brains of Shimano's XT Di2 electronic mountain groupset, allowing you to view data, control settings, and connect to the E-Tube Project application to customize your shifting preferences. Bluetooth and ANT+ enabled, the MT800 system display wirelessly connects to smart devices and cycling computers for seamless operation and control anywhere you go.
Details:
  • Displays system status of: battery level, gear position, shift mode and FOX iRD suspension position
  • Toggle audible shift notification chimes
  • Toggle between three Shimano Synchronized Shift modes available (S1/S2/Manual)
  • Digitally adjust front and rear derailleurs and provide numerical adjustment indicator
  • Wireless ANT / Bluetooth communication for customization and data utilization in the field with a smartphone, tablet, and other mobile electronics
  • Battery charging port
  • 3 E-Tube ports
  • D-Fly compatible
hah, nice - I installed one too (bought to help a user that was having problems pairing theirs).



Personally I don't see the use of this unit on a road bike, but that is just my opinion (I already have my Wahoo that displays the same data). It is perfectly fine to have a different opinion

That said, there are a couple of things I do like:
  • The audible shift notification chimes are pretty neat.. It beeps when I'm at either end of the cassette and also right before a (full) synchro shfit.
  • The button seems to work better than the one on my SM-EW90-A (not installed the EW-RS910 yet... soon..)
  • Because it's a display it is easier to tell the battery level, current shift mode and 'adjustment mode'. It also tells you the current RD / FD adjustment value

It'll probably stay on my second bike, because my EW-WU111 is moving to my new bike (Bowman Palace 3) soon.

The "D-fly compatible" in jmess' list means that this will do the same as a D-fly (BluetoothLE and ANT) - you can not install both this and a D-fly on the same bike (only one wireless capable device per Di2 bike allowed).
TerryDi2C is offline  
Likes For TerryDi2C:
Old 06-24-20, 04:01 PM
  #17  
Greatestalltime
Senior Member
 
Greatestalltime's Avatar
 
Join Date: Apr 2013
Posts: 141

Bikes: Tcr advanced sl & Protos

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 52 Post(s)
Liked 19 Times in 6 Posts
Originally Posted by Chi_Z View Post
bar end is the way to go, but if you have older handle bar you have to drill out a hole
Or, apparently, if you have Most Talon bar stem combo. Just bought some to replace the Metron 6D which has the hole pre drilled, but didnít fit with the f8 frame very well.

I was surprised the Most didnít have it. The drilling is no big deal though. I have had the shop do it on a pair of FSA and Deda. Both carbon. And now the Most which is almost finished.

Rs-910 is the only way to go imo. And as I said drilling the hole isnít a big thing.
Greatestalltime is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.