Help! Recommend me a front hub motor

[Bikes4two]

Topbike kit have motor drawings on their pages. Here's the one for the AKM75:

https://www.topbikekit.com/75SX%20Drawing.pdf

Thanks - they are currently my goto site for a good choice of motors and keen prices including the AKM75sx, Bafang G370, AKM100sx and AKM 100h (360w tho) and some other varients under their own label (eg TBK 100AD)

Around $200 for AKM100H motor, 26" wheel, KT sinewave controller, and KT900s display - not sure if that includes shipping but none the less, a good price so far.

 

[lenny]

Bafang 36V350W BPM2 Front Driving Hub Motor RPM 328

Bafang 36V350W BPM Front Driving EBike Hub Motor.

bmsbattery.com

 

[Nealh]

Thanks - they are currently my goto site for a good choice of motors and keen prices including the AKM75sx, Bafang G370, AKM100sx and AKM 100h (360w tho) and some other varients under their own label (eg TBK 100AD)

Around $200 for AKM100H motor, 26" wheel, KT sinewave controller, and KT900s display - not sure if that includes shipping but none the less, a good price so far.

They also have a shop on AliExp.

 

[Bikes4two]

In my original post I said:

• I’m looking to convert our tandem which is fitted with a Rohloff IGH and both bottom brackets are therefore eccentric.
• The eccentric clamps are castings on the underside of the BB which therefore excludes the possibility of a mid drive motor like the ...........Bafang BBSxx series or Tong Sheng TSDZ2 (the latter currently being my favourite.......).

and I also said:

but I’m keen to understand and experience a hub motor given those on here who favour them over mid drives

The trouble is, hub motors - they are cadence sensing and after having thoroughly got used to the torque sensing TSDZ2 and really, really REALLY liking the way is delivers power (as in proportionate to my own input), am I going to be disappointed with cadence sensing systems even with a KT torque simulating controller? I'm in a real quandary.

Going back to the issues with fitting a mid drive and the eccentric bottom bracket problem - I've spotted some pics of the new 250w epac legal CYC Photon which looks to have the potential to overcome the protruding BB eccentric fixings (pic below). From the Photon pics, there seems to be a considerable gap between the drive shaft that goes through the BB housing and the motor (pic also below). The problem here is the £997 price tag - eek, double eek!

Maybe the hub solution for £250 might be back on the cards .

 

[guerney]

You don't want cadence sensing Mr. mid-drive traitor , but I'm wondering how much gap you need. This is the BBS02, might be the same on the cheaper, cheerful and effective BBS01B. Maybe do a bit of filing? Removing 1 or 2mm might be ok? Unsure if a BBS01B would fit even after filing...

 

[Bikes4two]

And then there's the German Pendix eDrive system - that'd likley fit our tndem but not my wallet at £1500+

 

[guerney]

How much of a gap is there on the TSDZ2? Could filing away a mm or two from the protruding BB eccentric fixings allow it's fitting? The great thing is, you've got a TSDZ2 or 2 to attempt such. With a bit of luck the BB won't collapse.

Maybe the hub solution for £250 might be back on the cards .

You must find a way to preventing @Bonzo Banana becoming happy. I say keep the "Single point of failure" at any cost.

 

[Bikes4two]

You don't want cadence sensing Mr. mid-drive traitor ,

Lol @guerney - I think the clearances on the BBSxx are very similar to the TSDZ2 judging from other postings made by those enquiring about clearances and if they are then there's no chance of fitting the BBSxxx.

Of the four TSDZ2 I've now fitted, all in standard steel or ally BB frames, there's barely enough clearance to slip a gear cable outer through the gap.

I've even thought of modifiying the tandem frame to get rid of one of the eccentric BB's via some suitable adapters and welding and then getting rid of the BB securing lugs but that's all a bit scary especially given the price I paid for the tandem.

Mind you, if I can't electrify the tandem in some way I might as well sell it but given the 2nd hand market I'd only get a fraction of what I paid - where's my nearest frame builder with their welding torch!

 

[Bikes4two]

I think what I need is for @saneagle to expand on his dislike of crank drives more fully than what he said HERE and then I might be more encouraged to give a hub motor a whirl - @saneagle?

When you ride around with low power, you don't experience the worst disadvantages of a crank drive, and when you change from a normal pedal bike to an ebike, there's not much change to gear shifting. It's when you've been riding hub-motors for a while and you change to crank-drive, you can see how illogical, uncomfortable and stupid a crank motor is.

 

[guerney]

I know that front motors are not as powerful as rear hub motors but fortunately we are fairly able cyclists still and so just looking for a bit of assistance when the need arises.

I've never tried a hub driven bike or a TSDZ2. Someday I'll knock on @Woosh's door and demand a test ride of both, then of course run away without buying anything - he's bound to recognise me, my avatar is actually my passport photo. Until then, and if Woosh doesn't immediately call the cops at the sight of my contradirectional tusks, I can only speculate: With the low levels of assistance you require, the experience will be bearable if you turned coat and went hub happy... but it won't be the apparently magical experience of of riding your TSDZ2 conversions.

I would have gone for a front hub conversion kit for my Dahon Helios P8: longer lasting, mechanically simpler, cheaper etc. but I'm glad I wasn't able to (thanks Brexit), because it appears nothing short of a 30A controller and a more expensive battery than I have, can do the job my BBS01B conversion is doing ie hauling heavy trailers up hills with ease, while also providing me speed on the flat. Or I could try the Xongda two speed @saneagle suggested. Indecision and laziness has kicked the repair of the Dahon Espresso down the road, but I've bought a new chain, so that's something - next up, inner and outer brake cables to see how it rides as an acoustic (aarrgghh!) bike. All going well, I'll consider buying a brand new aluminium frame for it, because the old one may be haunted by it's deceased former owner, or blighted by fatigue. I'll hire an exorcist if there's any sign of pea soup.

I've even thought of modifiying the tandem frame to get rid of one of the eccentric BB's via some suitable adapters and welding and then getting rid of the BB securing lugs but that's all a bit scary especially given the price I paid for the tandem.

Yep.

 

[Bikes4two]

• I'm still prevaricating over the purchase of a hub drive as I'm very uncertain how a cadence sense system is going to compare to the TSDZ2 torque sensing arrangement.
• Millions of riders enjoy cadence sensing systems but........
• Anyway, I was rather hoping that @saneagle was going to expand on his comments I'd link to in post #29 above to pursuade me to part with my 'hard earned' for a hub motor.
• @Nealh - Neal: I know you have ridden hubs (esp the G370 with KT controller) and a TSDZ2 - so how do you find the different sensor systems in terms of the ride experience?
• I'm now back in contact with the lady to whom I sold the modified (as in fitted a KT Controller) e-Pendleton and I'm hoping to take the bike out for a spin to refresh after 22 months of TSDZ2 riding, on what that hub system feels like.
• Further, I helped her husband resurrect a busted Carrera (HESC motor) - I'm sure we fitted a KT controller to that too, so that'll be another test ride on a hub'd machine.

TORQUE SENSING BOTTOM BRACKETS

• I've only just become aware of this particular after market component for fitting to a hub motor's controller. (@Woosh 's company have this an an option on some (all?) hub kits apparently)
• There was a post back in August this year (LINK) where @Cavemann was enquiring about them but he got less than enthusiastic feedback from some - I'm wondering did he ever try one (or anyone else reading this)?
• So what do folks think of this adpatation - any good?
• And do you need a special controller to plug in the BB sensor or does it parallel up or replace one of the normal inputs e.g. the throttle?

Thanks all for your patience, but I know you'll put up with me (hopefully)!

 

[Woosh]

TORQUE SENSING BOTTOM BRACKETS

• I've only just become aware of this particular after market component for fitting to a hub motor's controller. (@Woosh 's company have this an an option on some (all?) hub kits apparently)

The BBTS (bottom bracket torque sensor) is at sea at the moment and should arrive in the next two to three weeks.

Here is the wiring diagram:

It's plug and play.

A minimum system consists of the BBTS, one DJ controller, one 44T chainring or 48T chainring, two (L+R) 175mm cranks, one LCD monochrome or colour.
You only need to add a 36V or a 48V battery and a 9-pin geared hub motor. The controller and LCD work very similarly to the KT system.
The cost of a minimum system without battery and motor is £110 with M5 LCD (black & white).

 

[Nealh]

BBTS needs a specific controller , one can't for instance use a std KT model.

Personally it boils down in my view to the riding style and ride you want, if you like the performance and extra rider input then the TSDZ is ideal, for just pootling around locally on errands or commuting then the hub is my choice in PAS1 . To me the TSDZ is wasted as an errand type drive.
If all you have been used to is the TS drive then one may feel the current control of a KT/hub is lacking but it does offer up a completely different ride feel and is more relaxed in use. However pop in to higher PAS levels and ones gets a different bike .

 

[Bikes4two]

And I suppose I better get to understand this box of tricks from Grin

 

[Bikes4two]

@Nealh -

• thanks for your feedback on your experiences which is rather along the lines of what I imagined.

• BBTS needs a specific controller , one can't for instance use a std KT model

• Indeed not but I see Casainho did before starting work on TSDZ2 OSF, wrote firmware (aka OSFW) for KT controllers.
• There's a lot of stuff in ES (link) and elsehwere (e.g. here) about this project and is going to take some getting into but at first glance would seem to offer something between the turnkey products from Grin in CAv3 (and soon to be Woosh) and the standard KT controllers.
• This quote from amberwolf of ES in answer to a question about BBTS says a lot

• There are at least two ways to do it.
  One is to use the Cycle Analyst v3 to read the various sensors and generate a throttle signal to run the controller, without modifying the controller in any way. You don't have to put the CA on the handlebars, it can go anywhere on the bike, so it doesn't interfere with your controller's display, etc. It's relatively simple to setup but more expensive.
  
  You don't even necessarily need a torque sensor to make the bike perform more controllably this way--the cadence sensor is enough because unlike the KT OEM firmware, the CA will actually let you use the pedals to directly control the motor system, either it's torque or speed or power. (the KT OEM firmware, like just about every similar controller, only turns the full power of the presently-selected-assist-level on or off based on whether or not it detects that you are or are not pedalling).
  
  
  Another cheaper more complicated way to setup is to use the Open Source Firmware OSFW discussed here:

@Woosh -

• that BBTS arrangement looks to be a very neat adaptation for hub motors (and with integral PAS too and a nice minimalist display), and has got me rather excited (lol)!
• Will the BBTS connecting cable be external to the BB shell (like the Grin Technologies Erider BBTS - now discontinued) or as the drawing implies require a hole in the shell?
• Have you or are you doing some field trials - I'm keen to know how the BBTS system shapes up in practice.
• I'm guessing there will be configuration options in terms of assist levels - will these be pre-set at the factory (or by yourselves) or user settable?
• Will you just be selling the BBTS kit as an option for your existing kit line-up or as a separate item (and then only to existing customers)?

Thanks, B4t

 

[Woosh]

Will the BBTS connecting cable be external to the BB shell (like the Grin Technologies Erider BBTS - now discontinued) or as the drawing implies require a hole in the shell?

the connecting cable is normally fed through a hole at the bottom of the BB shell or internally up the seat tube which is the way we plan use it to build our own bikes.

Have you or are you doing some field trials - I'm keen to know how the BBTS system shapes up in practice.

Not yet. We agreed with the manufacturers that the firmware may need to be revised later as we gain experience with the BBTS.

I'm guessing there will be configuration options in terms of assist levels - will these be pre-set at the factory (or by yourselves) or user settable?

There are 16 user settable registers P01 to P16. Some seem interesting like P12 but I don't understand exactly how they work, I guess, until I start using the kit:

P11：Assist sensitivity setting range：1-24
P12：Power start intensity setting range：1-5
P13：number of magnets on magnet disc
P14：Controller current limit setting default 15A range: 1-20A
P15：Controller undervoltage value

Andy hasn't re-written the user manual for the LCD yet.

Will you just be selling the BBTS kit as an option for your existing kit line-up or as a separate item (and then only to existing customers)?

The BBTS can be used with other controllers. We start with the recommended controller and LCD to avoid initial complications until we properly understand the device. We'll make it available for the Lishui controllers at a later date. The main problem is wiring. The throttle wire in the trunk Julet 8-pin 1T4 cable needs to be moved to the 5-pin BBTS output PAS+ TS.
We'll be selling the minimum kit with the DJ controller to experienced kit builders and as a normal option for our hub kits including the Q70 for Brompton.

 

[Woosh]

installation of the BBTS is similar to the Bafang BBTS, the parts are very similar: