Di2 issue on last ride

Nomadski

I Like Bikes
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LBS, Usually
Went out for a ride yesterday on my Dolan with Di2 and all was going well until we stopped under a bridge to get some respite from some heavy rain. When I got back on the bike I pedalled and the gears sort of 'crunched' when I changed it down. Didn't like the sound but afterwards they seemed fine so carried on.

Did a long downhill with no issues, then as I got towards the end of it I could hear a weird noise almost from bottom bracket area and the stability of the bike seemed a bit off. I stopped to check the bike over but couldn't see anything obviously wrong, checked brakes and made sure wheels were correctly locked.

Then a little further on a smaller downhill the noise and instability came back, I looked down and could see the chain resting on the chainstay but it was still firmly on the chainset. When I pedalled it resolved, when I stopped pedalling it came back.

It didn't seem to happen at lower speeds, ever. Seemed to be around 17mph or so it would happen, and mostly when going down an incline.

All gears were changing as they should, but if going downhill and I stopped pedalling the chain would flop onto the chainstay and the noise would come back. It may be psychologically just a result of the noise, but I'm sure I can feel instability.

I checked the battery situation and lights were normal (green for battery, red for manual shift mode).

i don't know if something has happened after I got that crunching in the gears when I had stopped.

Any ideas before I take it to a dude who knows about Di2?
 

ColinJ

Puzzle game developer
It sounds like what happened when my freehub decided to pretend it was fixed! The freehub had got all gunged up inside so I stripped it down, cleaned it and reassembled it with some light lubrication. It has been fine since.
 
OP
Nomadski

Nomadski

I Like Bikes
Location
LBS, Usually
Yeah my wheels are Kysrium Elites so Mavic too.

Wierdly before cleaning bike I’ve tried to recreate issue on bike stand. I can’t??!!
 

jamin100

Veteran
Location
Birmingham
Did the same on my wife's specialized Ruby (non di2) a few months back, as above it was the freehub in the wheel that need a good service. Its been fine ever since.
 

iluvmybike

Über Member
The Mavic aqueal starts of as intermittent but then will just become more & more persistent. It needs seeing to now
 
OP
Nomadski

Nomadski

I Like Bikes
Location
LBS, Usually
The Mavic aqueal starts of as intermittent but then will just become more & more persistent. It needs seeing to now
Cleaned the bike thoroughly and wheels, so will have a look the the freehub tomorrow.

Any particular recommendations on lube type for hubs, or just general plastic friendly grease?

Never taken a hub apart before... :ohmy:
 
Last edited:

Sharky

Guru
Location
Kent
Cleaned the bike thoroughly and wheels, so will have a look the the rear hub tomorrow.

Any particular recommendations on lube type for hubs, or just general plastic friendly grease?

Never taken a hub apart before... :ohmy:
I think it is a little oil you need, rather than grease on the internals of the freehub. Be careful when you dismantle, the tiny little pawls and springs have a habit of jumping away out of sight as soon as they see daylight. Best if you can work over a tray.

This might help

View: https://www.youtube.com/watch?v=eSR7luKf2t4
 
OP
Nomadski

Nomadski

I Like Bikes
Location
LBS, Usually
I think it is a little oil you need, rather than grease on the internals of the freehub. Be careful when you dismantle, the tiny little pawls and springs have a habit of jumping away out of sight as soon as they see daylight. Best if you can work over a tray.

This might help

View: https://www.youtube.com/watch?v=eSR7luKf2t4
Thanks, I just finished watching that video before reading your post :biggrin:

I suppose this will give me an excuse to clean the cassette while I'm at it.
 
OP
Nomadski

Nomadski

I Like Bikes
Location
LBS, Usually
Work on a metal tray with a couple of magnets on it, hopefully springs and balls will stick to the tray rather than bounce off.
Not sure if serious 😂

I’ve seen a couple of videos and it looks pretty safe so long as I slide the outer part off slowly.

Got a large black tray I’ll use anyway.

Took cassette off and it’s proper minging so maybe the freehub was just screaming at me for that!

Im still not sure I understand why it would cause the chain to lose all tightness and slack onto the chain stay when not under pedalling load though?
 

JhnBssll

Veteran
Location
Suffolk
Not sure if serious 😂

I’ve seen a couple of videos and it looks pretty safe so long as I slide the outer part off slowly.

Got a large black tray I’ll use anyway.

Took cassette off and it’s proper minging so maybe the freehub was just screaming at me for that!

Im still not sure I understand why it would cause the chain to lose all tightness and slack onto the chain stay when not under pedalling load though?
The magnet trick is real :okay:

An unhappy freehub has more drag. This causes the rotating wheel to turn the cassette rather than allowing it to freewheel, pulling the chain around with it and dumping it on your chainstay. At the point where the chain becomes tight underneath the friction is overcome and it starts freewheeling again. I suspect you'll have no further problems once you've serviced it :okay:
 
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