11 Speed Di2 Front Shifting Troubles

Discuss light weight issues concerning road bikes & parts.
LoggingMiles
Posts: 84
Joined: Sun Dec 01, 2013 3:46 pm

by LoggingMiles

Any ideas on next steps since it is not normal? I will take some pictures tonight of the wear.

goodboyr
Posts: 1390
Joined: Wed Jan 10, 2007 10:56 pm
Location: Canada

by goodboyr

Are you absolutely sure that your FD mount is rock solid? Some frames have mounts secured by screws. Others have rivets that may loosen.

LoggingMiles
Posts: 84
Joined: Sun Dec 01, 2013 3:46 pm

by LoggingMiles

Positive. It is the rivet type, but it is not loose. Completely removed everything from the bike before posting that last set of pictures to check for any play in the braze-on. Hand checked the torque when re-installing the cranks. Checked the torque on the chainrings. Torqued the FD to spec, used the support bolt.

The metal shavings have the completely baffled. I did not think that was normal, and not really sure what to do about it.

EDIT: I just got your PM, but I do not have enough posts to reply. I do appreciate the offer, but unfortunately we are a thousand miles apart.

goodboyr
Posts: 1390
Joined: Wed Jan 10, 2007 10:56 pm
Location: Canada

by goodboyr

Just out of interest, what torque did you use for the FD?

LoggingMiles
Posts: 84
Joined: Sun Dec 01, 2013 3:46 pm

by LoggingMiles

I used 7 Nm. That is what it stated in the dealer manual.

goodboyr
Posts: 1390
Joined: Wed Jan 10, 2007 10:56 pm
Location: Canada

by goodboyr

:? Ok. Stumped.

LoggingMiles
Posts: 84
Joined: Sun Dec 01, 2013 3:46 pm

by LoggingMiles

I will take pictures of the metal shavings (if any more remain on the chain) and back side of the chainrings on the crank tonight.

I guess my next move is swapping out the crank for the 6800 crank that my group came with and see if it is any better.

goodboyr
Posts: 1390
Joined: Wed Jan 10, 2007 10:56 pm
Location: Canada

by goodboyr

Take a straight side on view with fd in both positions ( big and small ring). Also see if you can get a closeup of where FD support bolt contacts.

LoggingMiles
Posts: 84
Joined: Sun Dec 01, 2013 3:46 pm

by LoggingMiles

Thanks, I will take several shots. I am fairly certain I will not be able to get a view of the support bolt with a camera, but I will try.

LoggingMiles
Posts: 84
Joined: Sun Dec 01, 2013 3:46 pm

by LoggingMiles

Here are the images. The first couple show you the metal shavings and the weird wear on the inside of the chainrings.

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goodboyr
Posts: 1390
Joined: Wed Jan 10, 2007 10:56 pm
Location: Canada

by goodboyr

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I'm wondering whether the initial not so great adjustment when you first installed, caused the FD cage to get bent and distorted under the shifting force. I think you said it actually got stuck on the upshift. That would put a huge force on the cage. For reference, I've taken a picture of my setup (of course its 9070 so not an exact compare), but in particular, note where the FD cage "hinges" to the actuator. Yours is not straight across, looks a bit distorted. Mine is straight across.

Image

goodboyr
Posts: 1390
Joined: Wed Jan 10, 2007 10:56 pm
Location: Canada

by goodboyr

Also note that my FD height is much lower than yours. I think yours is too high. No more than a dime thickness is the gap to the biggest tooth.

goodboyr
Posts: 1390
Joined: Wed Jan 10, 2007 10:56 pm
Location: Canada

by goodboyr

Actually, looking at it a bit more carefully, my tooth to derailleur gap is constant over the length of the derailleur, your gap increases along the length of the derailleur cage. So it starts out at the right gap at the front of the FD, then gets bigger and bigger towards the back of the cage.

LoggingMiles
Posts: 84
Joined: Sun Dec 01, 2013 3:46 pm

by LoggingMiles

I am going to go to a shop to see if the front of my derailleur is normal. In the meantime is the wear on the back of my chainrings normal? Or does that look odd to you? That is definitely where the shavings are coming from.

goodboyr
Posts: 1390
Joined: Wed Jan 10, 2007 10:56 pm
Location: Canada

by goodboyr

I've got 2500 km on my drivetrain, and there are no such marks on the inside of my Praxis rings.

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