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Posted

Hi,

 

I'm having a slightly odd shifting issue with my Ultegra 6700 rear shifter.

 

On the large gears (especially the largest 2 - a 23 and a 21), the chain struggles to drop down to the smaller sprockets. On the smaller gears, especially the smallest one (11 teeth), the chain struggles to climb up to the larger sprockets.

 

So basically the tension in the cable seems to low for the smaller sprockets, and too high for the larger sprockets. As a result, the problem is impossible to adjust away.

 

The last time I had this issue I managed to improve it by replacing the cable and housing. I tried that again (twice, to be sure that I hadn't screwed something up), but I'm still struggling to get good shifting.

 

I've also replaced the chain and tried a new casette, which make things smoother, but don't fix the shifting. The shifting action is smooth and easy, but just not accurate.

 

What are the odds that I've worn out the shifter (after about 30000 km)?

 

Any other thoughts?

Thanks

Posted (edited)

Bent derailleur hanger. Your LBS will straighten it out for about 50 bucks.

 

Given the slow progression of this problem - it didn't appear suddenly - and that I've never had even the slightest crash/accident on the bike, I suspect this is not the issue. I'll check it out though. I have a spare hanger that I can try. Thanks

Edited by Organic
Posted

Given the slow progression of this problem - it didn't appear suddenly - and that I've never had even the slightest crash/accident on the bike, I suspect this is not the issue. I'll check it out though. I have a spare hanger that I can try. Thanks

Had almost the same symptoms, it was a bent hanger and after several attempts to straighten it myself. I took it to a bike shop and they sorted it.

 

In my case though, the bike blew over in the wind (I lent it against a lamp post) and it landed on the drive side causing the bend

Posted

Given the slow progression of this problem - it didn't appear suddenly - and that I've never had even the slightest crash/accident on the bike, I suspect this is not the issue. I'll check it out though. I have a spare hanger that I can try. Thanks

 

New hanger probably won't sort it, often the bit of frame it's attached to is slightly out too. It needs to be properly aligned with the right tool. This is one of those things that it's best to get done by the bike shop unless you've got a hanger straightener. For the 50 bucks it'll cost you, it's worth eliminating as a cause.

Posted

New hanger probably won't sort it, often the bit of frame it's attached to is slightly out too. It needs to be properly aligned with the right tool. This is one of those things that it's best to get done by the bike shop unless you've got a hanger straightener. For the 50 bucks it'll cost you, it's worth eliminating as a cause.

 

Thanks. You're right - it's quite possibly an issue that came with the frame that's been exacerbated by wear. I'll organise to borrow an alignment tool to test with. I have little faith in the mechanics at my LBSs - too many bad experiences from too many shops.

Posted

Thanks. You're right - it's quite possibly an issue that came with the frame that's been exacerbated by wear. I'll organise to borrow an alignment tool to test with. I have little faith in the mechanics at my LBSs - too many bad experiences from too many shops.

 

Cool, hope you get it sorted.

Posted

A bent derailer hanger typically presents differently. Shifting will get progressively worse from the bottom up. It sounds to me you have great shifting in the middle bunch and poor at the top and bottom.

 

It has absoutely nothing to do with chainrings. Ignore that possibility.

Further, the chances that your derailer is worn is nil. Those things (except if SRAM makes them) go on forever.

 

I will look for the problem in:

 

1) Loose derailer/hanger.

2) Bent hanger (iin spite of my own reservations).

3) Cable problem, especially a kink or poor attachement at one of the stops.

4) Chain and jockey wheels contaminated with Squirt. The top jockey wheel, the guide pulley, must move freely, both rotational and axially.

 

Just as a note, a worn chain and cassette will still shift perfectly. It has nothing to do with shifting, only engagement.

Posted

It sounds to me you have great shifting in the middle bunch and poor at the top and bottom.

 

Further, the chances that your derailer is worn is nil. Those things (except if SRAM makes them) go on forever.

 

I will look for the problem in:

 

1) Loose derailer/hanger.

2) Bent hanger (iin spite of my own reservations).

3) Cable problem, especially a kink or poor attachement at one of the stops.

4) Chain and jockey wheels contaminated with Squirt. The top jockey wheel, the guide pulley, must move freely, both rotational and axially.

 

 

Thanks Johan. That's correct. It shifts correctly in the middle. It's reluctant to change down from the large gears, and reluctant to change up from the small ones. It seems like the problem is not too uncommon with 6700 and DA shifter/derailers.

 

Regarding the wear, I was thinking more about wear in the shifter mechanism than wear of the derailer. I probably use the shifter more than the average user for the same milage.

 

1. I've checked the derailer and hanger and tightened them already, and it made no difference. They were not particularl loose.

2. I'll check the hanger.

3. It could still be a cable issue. I have tried three sets of cable and housing (two new ones and the old one, all Jagwire). Replacing the cable and the housing did help the last time this happened (about 10000 km ago).

4. Interesting option. I'll definitely check that one out. The chain is new - I fitted it yesterday, with little effect. BUT: I did start using Squirt as a lube a month and a half ago, and it's quite possible / likely that the jockey wheels are clogged up. I've already decided to abandon it because of the goo that ends up everywhere.

 

Is it worth replacing the jockey wheels, and if so, is there anything with better bearings than the standard Ultegra wheels?

Posted

I had similar if not the same issue, i thought it was because swopping between my training and racing wheels. I had built the bike myself and i was very much out of ideas. Now i dont own a hanger alignment tool, well not yet, i was forced to take it to LBS, 50 bucks later bike shifting flawlessly.

 

Hanger bent even the slight bit from quickly changing between race and train wheels. I'm lazy so often rush to do last minute.

Posted (edited)

Thanks Meezo - will definitely get the alignment checked out.

 

I'll follow up once I manage to resolve the issue, whatever the solution ends up being.

Edited by Organic
Posted
Thanks Meezo - will definitely get the alignment checked out.

 

I'll follow up once I manage to resolve the issue, whatever the solution ends up being.

 

Any update yet?

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