2019 Merida E160 900e Di2 question

[Lad]

Hi guys,

On my last ride I did manage to insert a piece of hardwood tree branch between cassette and rear mech cage. Limped back home in one gear. After reset of Di2 the gears started to work (sort of) with lots of skipping gears. The jockey wheels were out of whack as the cage was bent outwards. After few attempts with a help of friendly mechanic from LBS we've managed to get a smooth shifting from gear 3 to 10 - apparently the inner and outer cage plate on the Di2 are bent beyond being able to get a full range - either top (1-8) will work or bottom (4-11) but not both.

The consesus was that replacing both inner and outer cage plate should bring me back into really flawles 5000km of mint shifting I've experienced so far.

I have the Shimano Part Numbers for the both plates, but the problem is to get them, and where I looked some of the option are "medium-long-extra long cage" varying between shops for the same Part No. Got confused (although not for first time with Shimano parts).
So my question is : any of you guys wit Di2 mech on Merida 900e know what is the length of the cage is (M, L or EL)?

 

[steve_sordy]

@Lad Did you or the LBS use a mech hanger alignment tool?

With a bang like that the hanger may have been slightly bent; not enough to see, but enough to have an effect. 11& 12 speed shifting is more sensitive to alignment. The tool is not cheap, but is very quick and easy to use, so LBS charges will be low.

 

[Lad]

@Lad Did you or the LBS use a mech hanger alignment tool?

With a bang like that the hanger may have been slightly bent; not enough to see, but enough to have an effect. 11& 12 speed shifting is more sensitive to alignment. The tool is not cheap, but is very quick and easy to use, so LBS charges will be low.

Thanks Steve,

I think you have a very valid point here. First thing I did was to check the hanger for damage with my EyeBall Mark2. (you as an engineer know, what I'm reffering to). No obvious bent on hanger was observed, so my LBS went with my assesment that hanger is good.
Given that the hangers are designed as sacrificial parts to prevent damage to the frame and derailleur on big hit, this could be my source of problem. Only thing I did not know that the slight bent cannot be easily detected by sight and there is a tool that can fix it. I will talk to my LBS about it.

Thanks again.

 

[steve_sordy]

After 3 trips to the LBS to fix an unnoticeably bent hanger at £10 each time, I bought one of these Park Tool versions (I had some vouchers).

https://www.chainreactioncycles.com..._dc|pcrid|161845658788|pkw||pmt||prd|546386UK

There are cheaper ones (as I later found out) that according to the reviews are OK. I used it to set up my hanger until it was spot on, not just +/- 3mm. Took a bit longer but I never had another problem with shifting on my then 11-speed bike. On my next bike, I broke the 12-speed mech in half and used the tool to ensure all was well before I fitted the new mech. It looked OK by mk1eb, but it was well out. When I snapped the new mech, exact same thing; looked ok but wasn't.

In terms of number of uses, I haven't got my money back yet vs the £10 per LBS, but the convenience and the speed makes it well worth-while.