Old Carrera Vulcan Bafang rear hub conversion

saneagle · Jul 19, 2023

Peter.Bridge said:
My niece (who is medical student) has asked to "borrow" my Claud Butler step through which I converted (which sounds like a good way of getting around campus !) I will have to give her strict instructions on battery care !!

So I could do with a "road bike" as well as my Boardman 29er BBS02B "mountain bike"

I bought an 22" XL Carrera Vulcan (26" wheels) for £70 off facebook (hope this isn't a Bike Shaped Object !) . The seller had paid £4000 for his new 29er mountain bike (non electric) - it looked very nice and the Carrera was sitting there gathering dust. (Unfortunately the Whyte Caledonian hybrid that I was looking at fell through - the seller said it was a 22 inch frame, but in fact it was a Medium)

View attachment 52855

I was going to use my existing Hailong 48v 20Ah (Samsung celled) downtube battery from my BBS02B conversion since I can't ride them both at the same time! Have bought a second battery mount (thanks @Nealh ) - loads of space on the Carrera to fit this.

So I was looking at Bafang rear hub motor kits without the battery - seems like loads on amazon / ebay / (I think these are the SWX02 ?)

Maybe this from AliExpress ? - they do a 26inch cassette option - I think Greenergy are an authorised Bafang seller and were very helpful with my BBS02B conversion
(I realise this is nominally rated 500w so illegal to use in the UK in public)

It shows n0(Rpm)= 380 , nT(Rpm) = 330 - what does this mean ?

Do I need to fit a torque arm ? Do I need to file the rear dropouts ?

There is a choice of displays - any recommendations ?
Do I need to worry about sine wave controllers / square wave controllers ?
Do I need to worry about speed based assist levels vs power based assist levels ? (I wanted power based)
On the link they talk about :
'Gifts: 1 PCS * Headlight + 1 PCS XT60 Port Connector Cable'

what is a XT60 Port Connector Cable ?

Assorted other bits if anyone has any advice /gotchas

I've ordered 2 puncture resistant tyres, more suitable for roads

I am going to put mudguards (I have some mountain bike mudguards that I never fitted) and pannier on (have a quick release seat collar with rack mounting that I will swap from the Claud Butler)

Will swap over to to Hydraulic Discs (although the tektro disks on the bike seem very good)

I will maybe remove the rear derailleur to make it into 1*8 rather than 3*8

Maybe will put on more raised 'dutch style' handlebars (and a mirror!) for a more upright seating position

Might need to swap over the pink bell from the Claud Butler step through to warn any racing road cyclists of my approach

Any comments ?

I've not seen it before, but I would say n0 is the no-load speed and nT the speed under some torque condition. If you're going to restrict it to 15.5mph, it's unsuitable because it won't be very efficient. You need 260 rpm for that, but if you want to cruise around at 20+mph, it'll be fine .

Bikes4two · Jul 19, 2023

I know nothing about hub kits - far too complicated for my limited mind
Do I need to worry about speed based assist levels vs power based assist levels ? (I wanted power based)

Click to expand...
By power based assist, do you mean torque sensing (rather than cadence sensing as used by Bafang hub motors)?
You could make things much simpler with a TSDZ2 mid drive kit with OEM display (and it's torque assist) - no need for all those questions then

Bikes4two · Jul 20, 2023

Ah gotcha - go for it then.

Peter.Bridge said:
I thought for my "everyday" bike a hub kit might be less stressful on the chain, gears, etc.

There's some absolute tosh talked about mid drive motors leading to excessive drive train wear.
Drive train wear is directly proportional to the power put through it (obvs) whether the power comes from your legs or the motor or a combination of both
Clearly though if with a cadence assist motor you only twiddle the pedals enough to activate the motor (or have a throttle), then power through the drive train will be near zero and of course it'll likely die of rust rather than wear.
So the fitting of a mid drive motor does not in itsself add to what would be normal drive train wear on an unassisted bike.

Nealh · Jul 20, 2023

I have used a few various hubs for my bikes whether local use or longer rides , in my earlier eapc use I mainly sought offroad distance rides in all sorts of places from bog , dust , rough, gnarly ,dry , trails ,fieds, bridles and any where between N& S Downs in my area inc the Downs.
I did have a BBS01 but gave up on that after a couple of controlelr issues and preferred the much better reliability from hubs. The hubs got me to the same places the BBS01 took me but with much better reliability.

Now I mainly use the bike as a transport tool , errands , commute and towing.
For my flat area use by far the best hub I have used is the present hub the tiny light Bafang G370 in a set of nice Surly forks it even tows my 100kg laiden trailer without complaint.
I also have a tsdz on the cargo bike and the only reason I didn't use a hub is to keep the bike as original as poss without wheel building.

Choose the drive that suits your use and terrain, that said I have had no issues with hubs getting me over terrain that a lot of users wouldn't navigate as they stick to tarmac highways.

sjpt · Jul 20, 2023

Bikes4two said:
So the fitting of a mid drive motor does not in itsself add to what would be normal drive train wear on an unassisted bike.

as long as the total power (motor plus rider) used on the assisted bike is the same as the rider power used on the unassisted bike.

Or to put it differently, fitting the mid drive motor doesn't add to drive train wear, but using it does.

saneagle · Jul 20, 2023

Bikes4two said:
Ah gotcha - go for it then.

There's some absolute tosh talked about mid drive motors leading to excessive drive train wear.

Drive train wear is directly proportional to the power put through it (obvs) whether the power comes from your legs or the motor or a combination of both

Clearly though if with a cadence assist motor you only twiddle the pedals enough to activate the motor (or have a throttle), then power through the drive train will be near zero and of course it'll likely die of rust rather than wear.

So the fitting of a mid drive motor does not in itsself add to what would be normal drive train wear on an unassisted bike.

Where did you get the idea from that chain wear is directly proportional to power? I looked for information about that, but couldn't find any. I can see it possibly being true if the increasing power comes from increased speed, but it actually comes from increasing torque on an ebike, which is the load on the chain. My intuition says that wear vs load should be an exponential relationship. I'd say that we're more interested in the load on the chain than the power going through it regarding wear.

Bikes4two · Jul 20, 2023

saneagle said:
Where did you get the idea from that chain wear is directly proportional to power?.....

Er, you've got me there - I was being general in that if you ride your mid drive bike in terms of speed and acceleration as you would say in your earlier days on an unassisted bike, then one wouldn't notice much if any difference in drive train wear - maybe an over simplified approach then?

I've now done 6,500+ Km on my TSDZ2 and I've changed one chain out at around the 4,000 Km mark with sprockets and the TSDZ2 chain ring still the original fitted items, and whilst I'm not religious about record keeping for when I replace things, my gut feeling is that I have not experienced any excessive drive train wear.

And even if my chain hadn't lasted as long as in my unassisted days, at £14 a chain every 10 months or so, I'll put up with that for what is in my view a great riding experience from a torque sensing mid drive.

saneagle · Jul 20, 2023

Bikes4two said:
Er, you've got me there - I was being general in that if you ride your mid drive bike in terms of speed and acceleration as you would say in your earlier days on an unassisted bike, then one wouldn't notice much if any difference in drive train wear - maybe an over simplified approach then?

I've now done 6,500+ Km on my TSDZ2 and I've changed one chain out at around the 4,000 Km mark with sprockets and the TSDZ2 chain ring still the original fitted items, and whilst I'm not religious about record keeping for when I replace things, my gut feeling is that I have not experienced any excessive drive train wear.

And even if my chain hadn't lasted as long as in my unassisted days, at £14 a chain every 10 months or so, I'll put up with that for what is in my view a great riding experience from a torque sensing mid drive.

You're right about being able to get a high mileage out of your drive train, but you must put that in the context of how much power you use or how much range you get from your battery and what battery it is. Obviously, if anyone rode a crank drive bike around with the motor switched off, there won't be any extra wear. There is some relationship between the power a motor uses and the chain wear, but you only give half of the story. We need the whole story to draw conclusions from your experience.

An average rider pedals with 60 -100w. A 250w TSDZ2 gives out a maximum of about 400w, so that will put a maximum of 5 times the stress on the chain, so we can conclude that the additional wear on a chain would be somewhere between zero and at least 500% of the bike without a motor. That value would depend on how much power the rider chooses to run with and some other factors.

guerney · Jul 21, 2023

Bikes4two said:
Er, you've got me there - I was being general in that if you ride your mid drive bike in terms of speed and acceleration as you would say in your earlier days on an unassisted bike, then one wouldn't notice much if any difference in drive train wear - maybe an over simplified approach then?

I've now done 6,500+ Km on my TSDZ2 and I've changed one chain out at around the 4,000 Km mark with sprockets and the TSDZ2 chain ring still the original fitted items, and whilst I'm not religious about record keeping for when I replace things, my gut feeling is that I have not experienced any excessive drive train wear.

And even if my chain hadn't lasted as long as in my unassisted days, at £14 a chain every 10 months or so, I'll put up with that for what is in my view a great riding experience from a torque sensing mid drive.

Bikes4two said:
Lots of things to think about - here's another one:

To get 60 miles out of a 400Wh battery you'd need to draw 6.67Wh/mile or less from it.

I have a TSDZ2 mid drive (36v 250w) and I typically burn 6-7Wh/mile as I nearly always only use the lowest power setting (ECO)

Thus if you do only get a 400Wh battery then you'll need to put in a fair bit of your own effort to achieve that sort of range and given that you say you live in a hilly area, you'll be keeping fit for sure.

I have achieved around 4.5Wh/mile by switching to zero assist on level or slightly downhill roads, which could be an option for you if you really do want to go no more than a 400Wh battery.

Bikes4two said:
I have achieved around 4.5Wh/mile by switching to zero assist on level or slightly downhill roads, which could be an option for you if you really do want to go no more than a 400Wh battery.

I think I use about 16Wh per mile. Compared to me, your use of pedal assistance is so low, it threatens to approach stretching the definition of the word "Assistance" to extremes. I'm about to change my cassette again (2nd, I think - the price for replacements is so low for my 20" wheeled Dahon Helios P8 folding bike, they don't register as being worth taking note of. I could shuffle through receipts, but can't be bothered) at the 3,978km mark, and I'm onto my third chain... For me, the tradeoffs are acceptable. My hauling of heavy bike trailers causes more wear than usual. For my bike, cassettes and chains don't cost much.

Bikes4two · Jul 21, 2023

Hi @guerney

I think I use about 16Wh per mile. Compared to me, your use of pedal assistance is so low, it threatens to approach stretching the definition of the word "Assistance" to extremes.

And therein lays the beauty of the ebike - varying levels of assist depending on your needs/likes - I've always loved cycling and the ebike is now my preferred type of bike

. It's true that 4.5Wh/mile will to some seem hardly worth making the effort, but that's an average over 30-40 miles riding were peaks of power nearer maybe 10Wh/mile are levelled out by miles cycled without any power (a mode I hasten to add, that has only come about recently as fitness has recovered somewhat thanks to the ebike).

I have cycling chums who are well into their seventies who have just gone electric but stuck with road bikes and batteries of 250Wh who regularly ride 60+ miles without exhausting the battery because they switch off assistance until the hilly bits or when weary towards the end of the ride.

Conversely I have a longtime pal who has only ever ridden electric and would never dream of pedalling to produce a sweat.

Horses for course!

saneagle · Jul 22, 2023

Peter.Bridge said:
Any guidance on which hydraulic disc brakes to fit ? Are they disc rotor dependent ?
I might have to get a longer cable (pipe?) because I wanted to fit swept back riser (Dutch style) handlebars
There seems a lot for sale where they are right rear / left front which is the wrong way round?

On all my bikes, I fit the Shimano integrated brakes/shifters. They work faultlessly and you get less clutter on the bars plus room for a throttle - 9 speed only. Discs are universal.

saneagle · Jul 24, 2023

Yes, you can use your 180mm rotors and adapters. In the worse case, you might have to put an extra washer between the caliper and adapter to stop the edge of the disc rubbing.

B02N-U Bluetooth	£24.14
P860ML(Multilingual)	£45.38
T1 Touch Screen	£84.31
DPC18(0-5 PAS)	£54.98
P850C	£41.74
500C	£30.51
DM03 Mini	£24.14
800S	£24.14
C961 BAFANG	£24.14

Old Carrera Vulcan Bafang rear hub conversion

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