Di2 Shifting issues - PLEASE HELP!

[Marchaugh]

Hello.
I have a 2016 S-works venge vias which has dura ace Di2 groupset apart from the chain rings which are praxis works 54/42, and the chain which is a KMC X11SL TiN-Gold. The wear of the parts is:
Chain - new
Cassette - about 2500 miles .

The issue I am having is when shifting between the 6 smallest sprockets it stutters and makes a lot of noise and sometimes won't even shift. The thing that is puzzling me is that this is happening when changing up and down the cassette. The mech hanger is relatively new and is aligned according to my mech hanger alignment tool.
I have come across some fairly puzzling problems with my bikes in the past and have always managed to get to the bottom of them. This one has me stumped, I have tried re setting up the gears according to the shimano manual but still the same issue. The firmware of all the groupset is also all up to date.
I have also noticed that my Di2 battery has drained unusually fast the last couple of times, I'm not sure if this is related but... ? The battery is only about 6 months old.
I look forward to your advice and ideas

 

[fossyant]

Your 'motors' could be on the way out. Remove the chain, and see if it still makes the noise when shifting with no load.

 

[JhnBssll]

The b screw could be wound too far out. Or the cassette could be loose on the freehub. Or the top jockey wheel could be loose or worn. Or the wheel could be off centre in the drop outs.

Lots of possibilities I'm afraid, but it's certainly unusual. How many miles has the mech covered?

 

[Marchaugh]

Thanks for all your suggestions. I'll check them all out. The mech has done less than 4000 miles.

The noise when shifting sounds like its the noise of the chain rubbing against the side of one of the sprockets as its trying to change, rather than the noise coming from the derailleur itself. But I'll give it a go shifting with no load.

What you said about the wheel being off centre in the dropouts is interesting as it has ultra light squewers which are almost impossible to do up tight. I'll give it a go with some more substantial ones.

 

[fossyant]

Change your skewers for Shimano or Campag. Keep seeing this issue.

 

[fossyant]

If it's lots of chain chatter then it's most likely drive chain alignment as has been suggested, cassette/jockeys. Check the cage isn't bent also.

I'd suggest checking the motor with chain and wheel out just to eliminate electrical/motor gremlins. Maybe push on the cage as it shifts to simulate some resistance. If that's all OK, then it's cassette/hub issues.

A mis-aligned wheel will cause shifting issues.

I find my SRAM 10 speed MTB mech is quite fussy about being 'spot on' even slightly out it won't shift well (I believe the same goes for 11 and especially 12)

 

[Ming the Merciless]

Install the latest software update and turn the DI2 off then on. A reboot may sort your gears.

 

[Marchaugh]

Thanks. The skewers sound a likely cause, I've always been a bit doubtful about an ultra light one for the back wheel. I'll check it all out later
Thanks @fossyant for all your suggestions.

 

[Marchaugh]

Install the latest software update and turn the DI2 off then on. A reboot may sort your gears.

It's all up to date but how do you turn it off and on?

 

[fossyant]

It's all up to date but how do you turn it off and on?

Microsoft restart - unplug the battery - I had an Alfa that needed that - turn it off and on again !

 

[Marchaugh]

Tried a lot of the suggestions tonight. 1.Replaced the skewer with a chunky one - still same problem
2. Tried shifting without any load - derailleur appears to be fine, making no strange noises.
3. Checked jockey wheels - they don't appear to be very worn.
4. Wound b tension screw to in and out extremes - as expected when wound in it was slightly better, but still couldn't stop it stuttering before a few of the changes.
5. The wheel looks tru
6. Replaced the mech hanger which I thought made a slight improvement but still same problem.
7. Made sure the cassette was mega tight.
8. Changed the wheel for a wheel of my other bike with a new cassette - this changed better than I've ever experienced with my original wheel. It was basically perfect.

What does this mean?
Is it the cassette? The cassette as far as I know has done less than 3000 miles and doesn't look worn.
Is it the wheel? I think this is the most likely cause of all my issues. I have also noticed a small crack where one of the spokes goes into the wheel. I'm not sure it's this is related but is that anything to be worried about?
If the cause is the wheel what can be done to fix it? Will it just need aligning and truing or do I need a new wheel?
I look forward to your responses.

 

[JhnBssll]

I would swap the new cassette on to the original wheel to see which was the culprit but if you've got a crack in the rim it needs replacing anyway. If there's play in the hub you'll need to check the bearings. If salvageable it may be worth building a new rim on to the hub, otherwise it's new wheel time.

 

[Broadside]

I agree, a crack on the rim spoke hole is not good.

The odd shifting could be down to a worn freehub body or bearings. Does the cassette have any movement flopping about at all?

 

[Marchaugh]

Thanks for your replies.
Oh dear not good. That wheel has only done about 4000 miles.
Will give it a go with the new cassette tomorrow just to make sure .
The cassette doesn't have any movement, fixed solid like it should be.

 

[si_c]

First thing swap the spare wheel cassette onto the new wheel and vice versa then try them again, if it is still the same with the same wheels then the cassette is fine but you need to reindex the DI2 positions.

With the crack at the spoke hole, is it an actual crack in the metal or is it anodised and the anodising has split? In either case keep an eye on it and see how it goes, if it gets worse or the spoke pulls through the rim it's time to replace it - if the wheel is under warranty then get it checked out sooner..