Di2 help....

Beatn1K

Active member
Jan 25, 2020
120
49
UK
I’m a newbie to the whole eMTB thing.
I have no experience with Di2, fitted to my Merida e160 900e.
How much ‘slack’ or free play should the arm have.
Battery out. Bike off. The arm can be moved enough to run the chain up the cassette whilst pedaling. How come it isn’t electronically locked into the gear it was left in...? Or does it ( the derailleur motor) need powering up?

I’ve found vids online bout indexing Di2 but nothing that convinces me to try it on my Merida.
Anyone know where to find a “ How to” for getting/ checking it’s set up right..?
The problem is the chain slips under heavier loads ( pedaling ) It’s annoying the crap out of me. Chain is within stretch limits and meticulously clean. So too the cassette.

Cheers
 

steve_sordy

Wedding Crasher
Nov 5, 2018
9,004
9,423
Lincolnshire, UK
How long has the chain been on the bike / how many miles has it done? It may be nothing at all to do with the Di2 system and everything to do with a chain and/or cassette that needs replacing.
 

pgtips

Well-known member
Patreon
Jun 3, 2018
312
279
Somerset
Surely the DI2 system needs to be powered up for the arm to be locked? Why would you ride the bike with it off anyway?

If the chain slips under heavier load sounds like the chain/cassette is worn out.
 

Beatn1K

Active member
Jan 25, 2020
120
49
UK
Thanks for the replies - I understand why you ask but...
Can I please have some info on indexing a Di2 derailleur? All I can find online shows switches I dont have and, as I explained, I’m not familiar enough with the system to transpose the advice from raceroad bikes with different hardware to my Merida...
Cheers

Should I post vid clip of ‘slack’ in derailleur arm....?
 

Beatn1K

Active member
Jan 25, 2020
120
49
UK
How long has the chain been on the bike / how many miles has it done? It may be nothing at all to do with the Di2 system and everything to do with a chain and/or cassette that needs replacing.
230 miles Cassette too...
Might be but they don’t look it. Very clean ( sonically cleaned every 45-50 miles ish) Not stretched going by chain tool...As per first post?
 

Beatn1K

Active member
Jan 25, 2020
120
49
UK
Surely the DI2 system needs to be powered up for the arm to be locked? Why would you ride the bike with it off anyway?

If the chain slips under heavier load sounds like the chain/cassette is worn out.
Why indeed...!
I’m not. The bike is in the work stand as I attempt to diagnose this issue...
Which is bugging the crap out of me...!
 

Beatn1K

Active member
Jan 25, 2020
120
49
UK
I have had a few troubles with the indexing on my 900e too. Turned out the derailleur attachment to the frame was loose... (Need to check pivot bearings regularly too, just sayin.)
Anyways, I had the DI2 lose index out on a ride because the derailleur was loose per the above. The following is how I solved the problem on that ride (from memory...).
I managed to fix it easy by holding the little nipple button on the bottom LHS of the display down for 4 secs or so until the display menu comes up. Then scroll through the menu with the LHS DI2 triggers - down to ‘RD protection reset’. Click the nipple button to select this option.

Use the LHS DI2 trigger to select OK (not Cancel). Hit the nipple button to execute. Then ride to rotate cranks (can’t recall if you need to have chain on biggest or smallest cog, logic suggests yes you do). Rinse and repeat until problem solved (either once or twice if I recall).
By the way, the ‘Adjust’ option in the above menu allows you to adjust the position of the derailleur if it gets a bit bent out of whack. I’ve adjusted mine a lot over time - now -11 off neutral 0:

Hope that helps.

Excellent - that is very helpful.
Its the 'adjust' function that I felt sure must exist...

Cheers....
(y)
 

Beatn1K

Active member
Jan 25, 2020
120
49
UK
So , I am going to have to admit defeat whilst I adjusted the Di2 and saw no improvement to the slipping issue...
I am a little worried that the cassette is mullered after all...perhaps the chain too ...And thats an expensive lesson with just over 300 miles on them..
So I fitted a brand new chain.( Wipperman) Its unrideable. The two rings I use most just wouldnt hook up at all... All the other rings seemed ok
Does this suggest the cassette needs replacing..?
Im a bit worried if I can goose a chain and cassette inside 300 miles.
Its an expensive lesson...I thought i was maintaining it ok - and backing off on gear changes ( although the motor does linger after the pedal stroke is stopped?)
Think Ill go back to the knackered chain til I can suss out whats afoot...!
 

Bonz

Member
Jul 2, 2018
141
99
New Zealand
I’m a newbie to the whole eMTB thing.
I have no experience with Di2, fitted to my Merida e160 900e.
How much ‘slack’ or free play should the arm have.
Battery out. Bike off. The arm can be moved enough to run the chain up the cassette whilst pedaling. How come it isn’t electronically locked into the gear it was left in...? Or does it ( the derailleur motor) need powering up?

I’ve found vids online bout indexing Di2 but nothing that convinces me to try it on my Merida.
Anyone know where to find a “ How to” for getting/ checking it’s set up right..?
The problem is the chain slips under heavier loads ( pedaling ) It’s annoying the crap out of me. Chain is within stretch limits and meticulously clean. So too the cassette.

Cheers
Probably of no help but the clutch on my derailleur caused a similar problem. There is a small clip which holds the clutch select lever in place, it had come loose which caused the chain to be so loose it actually came off.
Easy to check by removing the clutch cover.
Or maybe a bent derailleur hanger??
 

brash

Well-known member
Jul 19, 2019
105
130
Aus
So , I am going to have to admit defeat whilst I adjusted the Di2 and saw no improvement to the slipping issue...
I am a little worried that the cassette is mullered after all...perhaps the chain too ...And thats an expensive lesson with just over 300 miles on them..
So I fitted a brand new chain.( Wipperman) Its unrideable. The two rings I use most just wouldnt hook up at all... All the other rings seemed ok
Does this suggest the cassette needs replacing..?
Im a bit worried if I can goose a chain and cassette inside 300 miles.
Its an expensive lesson...I thought i was maintaining it ok - and backing off on gear changes ( although the motor does linger after the pedal stroke is stopped?)
Think Ill go back to the knackered chain til I can suss out whats afoot...!

Classic symptom that the cassette is cactus.

Either go back to the old chain that meshes with that cassette or go all out and new cassette.
 

Stuart569

Well-known member
Jun 24, 2019
128
111
NE Scotland
Chewing up the 2 smallest fogs
So , I am going to have to admit defeat whilst I adjusted the Di2 and saw no improvement to the slipping issue...
I am a little worried that the cassette is mullered after all...perhaps the chain too ...And thats an expensive lesson with just over 300 miles on them..
So I fitted a brand new chain.( Wipperman) Its unrideable. The two rings I use most just wouldnt hook up at all... All the other rings seemed ok
Does this suggest the cassette needs replacing..?
Im a bit worried if I can goose a chain and cassette inside 300 miles.
Its an expensive lesson...I thought i was maintaining it ok - and backing off on gear changes ( although the motor does linger after the pedal stroke is stopped?)
Think Ill go back to the knackered chain til I can suss out whats afoot...!

The way you change gear or maintain the bike isn't why you're chewing up the 2 smallest cogs. Being in them so much in boost/turbo mode will be. A larger front chainring can help with this. I had and still have to some extent the same problem as you. Now I just change the 3 smallest cogs on the cassette and the chain when I start to get slip which works out at £28 compared to £57 for a new Cassette and chain
 

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