Ultegra 6703 Shifter Woes…

Remember how Paul Harvey would often times introduce an item with “Here’s a strange…”? I’ve got one!

The Ultegra 6703 left-hand / triple front derailleur shifter on our Calfee tandem was for inexplicable reasons not working when we headed out for a Memorial Day ride from the house. I didn’t discover this until we were heading into the 8% grade out of our community and attempted to shift the chain from the 53t chain ring to the 44t chain ring and could not get the ratchet mechanism to release with the actuation lever. Just nothing happening there and even “tugging” on the exposed cable had zero effect: on the Campy shifters it would sometime get a little crossed up and that gentle tug would free things up.

Mind you, we’d just spent a couple days riding the bike with zero issues down in Valdosta at the Georgia Tandem Rally in relatively good weather. The tandem went back in the enclosed truck bed after each ride and went from the truck bed to the garage after returning home. As I said, very strange…

After we grunted our way to the top of the 1/8 mile climb in the 53t x 32t I pulled the bike off into a cul-de-sac and confirmed there wasn’t much I could do to field repair the shifter. So, I asked Debbie if she wanted to pack it in and head back home, or continue our ride with a reduced number of gear options. She said she was game for riding the bike as a 10 speed so I used a 4mm wrench to loosen up the pinch bolt on the front derailleur and manually adjusted the cage to support riding in just the middle ring.

The ride was fine, notwithstanding a couple of our faster descents where we spun-out and just coasted until the revs dropped back in the 120’s or so where our feet could keep up. In fact, it actually felt pretty good doing a bit more spinning than we sometimes do with the 53t ring at our disposal.

Back at the house I disconnected the in-line cable connector to free up the front derailleur cable so I could check for cable binding and push the cable end out of the shifter body. There wasn’t any binding on the cable, but just getting the cable out of the shifter body caused the return spring & ratchet mechanism to begin working again: weird. With the rubber shifter boot pulled out of the way I could see enough of the internal components to conclude that it wasn’t really any grit, grime or corrosion that might have caused the release ratcheting mechanism not to work.

I gave the internals a shot of silicone spray and a blast of compressed air just to clean out anything that may have been mucking up the works, put it all back together and voila, it was working once again. However, the upshift / brake lever definitely felt like it was not moving as swiftly as it should. So, while it’s working I’m thinking that it’s still harboring some issues that I’ll need to investigate.

In the back of my mind I want to say that these newer Shimano STI shifters can actually be worked on and “fixed” when minor issues crop-up, unlike the earlier models which were not serviceable in any way. And, while I’m not 100% certain, I believe there may be a threaded pivot bolt that runs through all of the internals which, if it becomes loose at all, can allow the internal mechanism to bind. So, I may have to pull the lever off the handlebars to access if that pivot bolt is still holding torque or if it’s somehow come loose. More to follow.

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About TG

I've been around a bit and done a few things, have a couple kids and a few grandkids. I tend to be curmudgeonly, matter-of-fact and not predisposed to self-serving chit-chat. Thankfully, my wife's as nice as can be otherwise we'd have no friends. My interests are somewhat eclectic, but whose aren't?
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4 Responses to Ultegra 6703 Shifter Woes…

  1. Jack T Allen says:

    You have much more experience with bicycle mechanical issues than I, but when I have (twice) had similar issues with the derailleur, replacing the shift cable was the fix.
    Jack

    • TG says:

      True… frayed cables inside the shifter body are quite often the cause of shifting issues on both STI and Campy Ergo systems, but in this case the cable is still in fine condition as is the housing and ferules. But, to your point, derailleur cables are one of the first things to check when a shifter begins to act up, especially if you can’t remember when you last replaced them!

  2. leissp says:

    Reblogged this on leissp and commented:
    As Tandem enthusiasts I find this site really great

  3. Greg Kniseley says:

    Known issue, probably will be the alllen headed fastener accessed from underside as you describe. They backed out the left lever on 2 sets of 6703s, used fine thread Loctite In recent “repair.”

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