Tick Tick Tick Twang Revisited

[Charliefox]

Discovered the wonderful ease with which Bafang rear hubs can be taken apart.The Pre 2015 models at least. Held together by 6 counter sunk cross headed bolts which were firm but not desperate. Say 5 minutes. Then wasted another 20 by taking off cassette gear cluster to acess another 6 bolts circulating the plastic cassette freewheel cone. Took these out to find they were very short and just filled the holes! Nothing else!
Then undid axle bolt on disk brake side before giving a gentle tap and all was revealed.3 wrecked nylon gears and a rusty looking clutch plate. Surprised to see 6 (everything in sixes?) cut outs on the windings side. I wonder why when the gear section was covered in thin, very black grease. As to replacements, the gears are £15.43 from China, of which £7.09 is the air freight. Not sure about the clutch plate as it is a bit rough in operation due perhaps to rust getting inside it and I noticed gear wheel scrape marks on it's base. Did those cause the nylon cogs to crack open? Still not expensive though as clutch with 3 gear wheels is only £23.75 of which airfreight is £9.86. I will probably be hit with VAT and collection charges on this order but that is the price for having to buy from China. I can't find any in Europe. So it looks like an easy fix. I was worried that twiddling with the throttle a bit after the gears jammed might have blown a mosfet or something else but on mounting just the electric side in the drop outs and connecting it up, it ran silently and smoothly. Now I have to wait several days in lovely summer weather up here without the bike. Luckily I have 2 other non MTB to get to town and a non electic(groan groan here comes a hill!) MTB if I get really desperate!

 

[Nealh]

The six short threaded screws behind freewheel are important as they thread in to the clutch back plate, the clutch it self doesn't spin but the outer hub spins on the inner 3 wheels of the clutch.
Be sure once the clutch assembly is in place to rotate it to locate and thread them back in.

Your hub has seen some serious heat or abuse by the looks of it. my one at 3k miles was very good inside though needed to replace a worn bearing so IIRC, I renewed LHS bearing and the large central 6012rs bearing and for the sake of a few quid two in the cassette freehub body.
For grease I used lithium moly black grease I've had for donkey's years another option is Aeroshell 22.

I've not been caught with duty buying from GBK, bite the bullet and get a new clutch gear as well also whilst a part renew all bearings. Cheap enough off ebay all sizes are marked on them.

 

[Charliefox]

The six short threaded screws behind freewheel are important as they thread in to the clutch back plate, the clutch it self doesn't spin but the outer hub spins on the inner 3 wheels of the clutch.
Be sure once the clutch assembly is in place to rotate it to locate and thread them back in.

Your hub has seen some serious heat or abuse by the looks of it. my one at 3k miles was very good inside though needed to replace a worn bearing so IIRC, I renewed LHS bearing and the large central 6012rs bearing and for the sake of a few quid two in the cassette freehub body.
For grease I used lithium moly black grease I've had for donkey's years another option is Aeroshell 22.

I've not been caught with duty buying from GBK, bite the bullet and get a new clutch gear as well also whilst a part renew all bearings. Cheap enough off ebay all sizes are marked on them.

I assume the six bolts you mention are the ones shown in the pic of the inside of the hub surrounding the central gear which drives the 3 nylon gears. Yes, the o/s outer plate on the chain side looks bad but only from chain jumping the largest ring and jamming between it and the casing.Yes, I will order clutch with gears from GBK. Can you remember which postal service you chose? There is quite a variety. I was thinking UK Post or RMS2.
I still wonder what those bolts around the cassette hub were for since they do not go past the inner face of the hub wall. If they did they would catch on a thin edge of the hub I saw below.I see that there are castings by each bolt..scraped by by chain (now replaced and behaving itself) and wonder if something light was bolted on, the bolts being too short for anything of a drive nature.

 

[anotherkiwi]

I will probably be hit with VAT and collection charges on this order but that is the price for having to buy from China. I can't find any in Europe.

Ahem...

https://www.ebike-solutions.com/de/shop/motoren/ersatzteile-fuer-nabenmotoren/

 

[Nealh]

GBK p&p I use registered air mail direct uk.

 

[Charliefox]

GBK p&p I use registered air mail direct uk.

Thanks Nealh. Have ordered.

 

[Nealh]

An item i ordered on 15th arrived this a.m via R.M normal post.

 

[Charliefox]

Ahem...

https://www.ebike-solutions.com/de/shop/motoren/ersatzteile-fuer-nabenmotoren/

I tried Ebike solutions but they are out of stock of the Bafang CST/BPM clutch at present. They do have the gears though. Somewhat pricey postage but that's DHL for you.

 

[Charliefox]

GBK p&p I use registered air mail direct uk.

I put in an order for the clutch with gears but discoved today, 5 days after order went in, that there are 2 types of 4 notched clutch. The boss on mine is 10mm depth. The other is 3mm. See pic from Anna at Greenbike. Guess what..they don't have mine! So altering order for 3 gears only. All this messing about, emails passing to and fro re measurements made me realise a 7 hour time difference can be a real pain.Their emails came in around 4am, by the time I had read then and replied it was too late in the day to speed things on.
With all the millions of Chinese Hub motors on the road in China you would have thought there would be a more widespread spares supply network.Perhaps I had better hope my clutch never fails. Have soaked it in synthetic engine oil for several days and cleaned all rust off it.

 

[Charliefox]

The six short threaded screws behind freewheel are important as they thread in to the clutch back plate, the clutch it self doesn't spin but the outer hub spins on the inner 3 wheels of the clutch.
Be sure once the clutch assembly is in place to rotate it to locate and thread them back in.

Your hub has seen some serious heat or abuse by the looks of it. my one at 3k miles was very good inside though needed to replace a worn bearing so IIRC, I renewed LHS bearing and the large central 6012rs bearing and for the sake of a few quid two in the cassette freehub body.
For grease I used lithium moly black grease I've had for donkey's years another option is Aeroshell 22.

I've not been caught with duty buying from GBK, bite the bullet and get a new clutch gear as well also whilst a part renew all bearings. Cheap enough off ebay all sizes are marked on them.

Not sure I would use any oil based grease on my new nylon cogs having read elsewhere that it can soften the nylon (which is derived from oil too?)
So I coughed up for a tube of Mobil Mobilith SHC 220. A red lithium grease with a synthetic base and supposed to be extreme pressure too. Having said that, I could probably have got away with using some Stendec Fork grease since the makers said it should be OK.Also High pressure and synthetic.

 

[Charliefox]

An item i ordered on 15th arrived this a.m via R.M normal post.

I had better hope that my clutch never fails, as I received this message from Greenbikekit this morning.

From: "info@greenbikekit.com" <info@greenbikekit.com>
To: chris <chris@charliefox60.plus.com>


Dear Chris,

We cannot supply it in the future because Bafang does not produce it any
longer.

This is refering to the clutch with the 10mm boss. I wonder if it is possible to order the 3mm boss one and pack 7mm worth of washers under it when assembling? It makes you realise that aftermarket spares for hub motors (Bangfang mid motor spares seem more widespread) is not that great.

 

[Nealh]

The nylon gears are held on via circlips so renew gears only.