Could eddy currents be causing this riding through treacle effect

[MikeS]

Sorry - just realised you asked me to check both wheels for free spinning - I will try the front wheel this afternoon as well
Mike

 

[Artstu]

Anyway this afternoon I am going to rig the bike so I can sit on it and pedal without the chain connected.

You'll quickly get a speed sensor error with that and the motor will pulse on and off.

 

[MikeS]

ah - that kyboshes that idea then

 

[Deleted member 25121]

That's interesting - so if there's no load (lights) on a dynamo the only resistance it's providing is the frictional losses in the various moving bits?.

Yep, that's right. Good luck with the experiments...

 

[MikeS]

Results of experiments so far.
Both wheels spin freely and no brake binding.
With chain disconnected the pedals spin freely and soundlessly forwards but there is resistance and noise to backpedalling - doesn't sound like a bad grindy sort of noise though.
Pedalling forwards for some considerable time did not trigger the problem.
Connected the chain and did the same experiments - bike was in a bike stand so there was no load for the torque sensors to pick up so the motor didn't cut in on any setting. Did 2 miles (off the ground) and still no sign of the problem issue.
The chain and cogs and chain ring did make more noise than I'm happy about. The chain is showing .75 wear so it needs changing (I'm waiting for another owner to confirm the normal length).
The rear cassette teeth look fine. I thought the chain ring was worn as most of the teeth are pointed. (pic attached) but then found an article that said single chain rings are made with pointy teeth. But then again I found this pic of a Bosch ebike chainring and it has FLAT headed teeth - was mine like this originally?


Here's a pic of mine:

 

[MikeS]

I’m trying to post a video so you can see and hear the crank turning. I have got it small enough but the system doesn’t like the .mov extension. What format is acceptable?
Mike

 

[Artstu]

Guessing it needs to be hosted elsewhere.

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[MikeS]

dont think so. It went through uploading the .mov file which I had drastically reduced in size but then said it didn't like the file extension. This was to attach a file to the post rather than embed it.
Mike

 

[MikeS]

Here's a try to a link for embedding:
https://flic.kr/p/2gjFNAd

 

[MikeS]

and that didn't work either. What part of the URL from Flickr does the system want? does anyone know
Mike

 

[MikeS]

I asked you twice already, did you unclip the chain to test how free the crank turns backwards, but you haven't replied. That would have given you an answer to the condition of the bearings, which are the most logical culprit.

I don't know whether you were able to see the video clip that I put up, but with the chain off the pedals whirr around in the forward direction almost soundlessly and will continue spinning for several revolutions. When winding them backwards there is a noticeable resistance and it's quite noisy but it's not a nasty sort of noise. If I tried to spin them backwards I don't think they would do even one revolution.
Mike

 

[vfr400]

The video doesn't work. Why don't you put it on Youtube?

 

[MikeS]

It’s up and working on Flickr. It’s just trimming the URL that’s puzzling. Here’s another go. All done on my phone this time

https://flic.kr/p/2gjFNAd https://flic.kr/p/2gjFNAd

 

[vfr400]

Still doesn't work. Use Youtube!

 

[MikeS]

Still doesn't work. Use Youtube!

I had stopped using Youtube because it will not now let me in unless I do it through my Google Account - which I had stopped using a few years ago when they spooked me .
Never mind - the bike is going in to Halfords today and I will report back.
Mike

 

[Artstu]

I

I see that the battery lights come on in reverse
IMG_2626.TRIM by Mike5100, on Flickr

 

[vfr400]

That looks normal enough, but it doesn't really test the bearings. You should turn the pedal by hand with a bit of load on the crank to feel for any bearing roughness.

 

[MikeS]

That looks normal enough, but it doesn't really test the bearings. You should turn the pedal by hand with a bit of load on the crank to feel for any bearing roughness.

Yeah - i snipped that bit off the video to keep it short. The turning by hand in the forward direction felt silky smooth and almost soundless.
Mike

 

[MikeS]

I

I see that the battery lights come on in reverse
IMG_2626.TRIM by Mike5100, on Flickr

Wow - yes I hadn't noticed that - is it significant?
Mike

 

[Artstu]

Wow - yes I hadn't noticed that - is it significant?
Mike

Not sure to be honest, I know my Bosch classic can come alive when moving the bike too, forget the exact scenario that does it though.