HOT: Active* forum members generally gain 5% discount at starbike.com store!
Weight Weenies
* FAQ    * Search    * Trending Topics
* Login   * Register
HOME Listings Articles FAQ Contact About




Post new topic Reply to topic  [ 6 posts ] 
Author Message
PostPosted: Fri Apr 12, 2013 5:52 pm 
Offline

Joined: Thu Feb 07, 2013 7:45 pm
Posts: 5
I purchased some of the DigiKey momentary switches, http://www.digikey.com/...t-detail/en/MTG72AD2 I originally used with Ultegra Di2 and they worked without a problem on my P4.

I recently purchased a P5 and built the bike with Di2 7970 and used the DigiKey switches. Everything is stock besides the cable splices on the front wire harness and the Digikey switches. The problem is that I can not get clean shifting in the rear. The shift will happen but not stop. The rear derailleur will continue to engage on it's own and make additional, random, shifts. I can hear it continue to engage when the Digikey switch is in an open position.

I am curious if anyone has run into this problem. I have not done much debugging on this yet. It is only a problem on the rear and not the front. It seems to me it could be a couple of problems

1) There is a short of some kind in my wiring causing the issue. I think this is most likely. But I have done many, many wire splices and never had a problem before.
2) These momentary switches work find with Ultegra Di2 but are not compatible with the old (7970) Dura Ace. The thinking being that the little black boxes that I harvested cleanup the signal from these switches to only send one shift to the rear derailleur with Ultegra.
3) The rear derailleur is defective. I actually believe this to be the most unlikely but you never know.

I am curious if anyone else has ever run into this issue? Any tips appreciated.

What I plan on doing

1) Disconnect the DigiKey switches and manually short the wires and see what happens with shifting. If this fixes it I plan on swapping the front and rear Digikey shifters and see if this helps. If this does not help then undo my wire splices and try the same thing with the wires directly out of the front wire harness. If still have issue with wires directly out of the front wire harness then I have a tough decision. Either replace everything with stock so purchase the Shimano front shifters and a new front wire harness that has not had the wires cut. Or just replace the rear derallieur. Thoughts?

2) The other option is just replace the 7970 with my Ultegra Di2 which I am not really using. But this would require me to re-cable the bike. Move the 7970 to different bike.

Thanks for any help in advance!


Top
 Profile  
 
PostPosted: Fri Apr 12, 2013 6:33 pm 
Offline

Joined: Mon Jan 21, 2008 12:09 pm
Posts: 2466
Ultegra di2 and DA7970 are incompatible. Different programming, signals, software, and hardware. Had you tried this with the newer DA di2, I don't think you would have a problem. But I think the issue lies in the incompatibility of the two systems.

_________________
TED
Schoorl, Noord-Holland, Nederland
Bike Pics
English Custom Steel Internal di2
Litespeed Ghisallo


Top
 Profile  
 
Posted: Fri Apr 12, 2013 6:33 pm 


Top
  
 
PostPosted: Sat Apr 13, 2013 6:08 pm 
Offline

Joined: Thu Feb 07, 2013 7:45 pm
Posts: 5
Sorry if I confused. No I am not trying to mix the systems. I am using all 7970 stock parts except using the DigiKey momentary switches. I included talk of Ultegra DI2 only because the exact same switches did work with this setup without issue.


Top
 Profile  
 
PostPosted: Sat Apr 13, 2013 10:10 pm 
Offline
User avatar

Joined: Sun May 25, 2008 10:12 pm
Posts: 599
Location: italy
on 1st post , the link does not work

_________________
http://eliflap.it/


Top
 Profile  
 
PostPosted: Sat Apr 13, 2013 10:44 pm 
Offline

Joined: Tue Feb 01, 2011 6:53 pm
Posts: 17
Honestly, I think a switch is switch so I doubt there is any kind of compatibility issue where it works with Ultegra but not Dura-Ace. I would get a multimeter and test the switch to see if there is an issue with the contacts. If I understand you correctly, you are splicing these switches in addition to the existing shifters, so if the existing shifters work then the switch should as well. My guess is the contact is not fully releasing after you depress the switch, a multimeter will verify this. Those Digikey buttons are ridiculously expensive, it would probably be cheaper to nab the remote buttons from something else and use those.


Top
 Profile  
 
Posted: Sat Apr 13, 2013 10:44 pm 


Top
  
 
PostPosted: Sun Apr 14, 2013 12:28 am 
Offline
Shop Owner

Joined: Sat Jun 13, 2009 4:02 am
Posts: 1966
Location: NoVA/DC
A switch is a switch on 7970. A switch is not a switch on 6770. You mention harvesting a little black box for the thing to function on the 6770 setup. Are you using it on the 7970 parts too? if so, leave it off, just use the basic switch.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 6 posts ] 


Who is online

Users browsing this forum: Bing [Bot], duckson, Exabot [Bot], Frankie13, Google [Bot], Jere, Rick, rijndael, rmerka, sanrensho, UncleJamsArmy, Yahoo [Bot] and 40 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

   Similar Topics   Author   Replies   Views   Last post 
There are no new unread posts for this topic. half-shifts after hitting bumps?

[ Go to page: 1, 2 ]

in Road

Mize

27

810

Wed May 07, 2014 11:57 am

mattr View the latest post

There are no new unread posts for this topic. Clean looking way to run electrical cables along brake cable

in Road

bigcalves

5

886

Thu Oct 03, 2013 4:20 pm

53x12 View the latest post

There are no new unread posts for this topic. DT 240S Freehub Issue

in Road

ultimobici

11

943

Tue Nov 05, 2013 7:15 am

ultimobici View the latest post

There are no new unread posts for this topic. Issue with Di2 Front Derailleur

in Road

AndreLM

11

507

Thu Sep 11, 2014 1:22 am

AndreLM View the latest post

There are no new unread posts for this topic. Installing 6870 Di2 Issue

in Road

Carrots

5

611

Wed Jun 04, 2014 8:43 pm

tnc1970 View the latest post


It is currently Tue Sep 30, 2014 6:41 pm

All times are UTC + 1 hour




Advertising   –  FAQ   –  Contact   –  Convert   –  About

© Weight Weenies 2000-2013
hosted by starbike.com


How to get rid of these ads? Just register!


Powered by phpBB