Benchie

I’m thinking of transferring my BBS01 mid-drive kit from a hybrid bike onto a Cannondale Topstone gravel bike that is gathering dust in my shed (I know - it’s a real waste!). The main problem I can foresee is mounting the C961 display onto drop bars which have a diameter of 31.7mm. The display itself should be OK but the remote button / switch assembly is never going to fit (it fits to a bar diameter of 22mm). Is there a compatible display with integral buttons that will mount to a large diameter bar (32mm)? I’ve seen pictures of a C963 that might work, but cannot find anywhere that stocks one. In an ideal world I’d love a small discreet display like the SW102 or 500C but both appear to be for 22mm bars only. Any suggestions?

Hi Hilly, another thing to consider when deciding whether to go centre drive or hub motor is what type of wheel hub the donor bike is set up for (in terms of the frame). The Planet X London bike that you linked looks like it has a QR through axle on the front, but can’t see what is on the rear from the pictures. Centre drive looks like it would be easier to fit.

Thanks awol, that’s the same address I’ve been using for Bonnie. No idea why the messages get bounced back - I’m using the same email account that I used when I ordered it 18 months ago. I’ll persevere!

Indeed, that is great customer service. I’ve just removed my YTW-06 motor from my bike because it got very noisy. The ‘freewheeling’ clutch type noise got a little worse, but it developed a rattly bearing type noise when pedalling in excess of the motor assist speed. Strangely , it was still relatively quiet when the motor was providing assistance. Gave up and fitted a BBS01B instead (thanks Woosh!). Out of interest, did you have any problems getting in touch with Bonnie at Xiongda? I tried to email her from two different accounts and both times the messages got bounced. I’d still like to fix my motor if possible.

Hi cwah, I’ve covered about 350 miles since adding the YTW-06 motor. In terms of noise, I’d say with ‘power on’ it’s about the same as when it was new, no real change. Although to be honest, it’s not really that noticeable. I’d say it’s a little noisier in assist levels 1 and 3 (no idea why). The noise in a ‘power off’ condition sounds a little like the brake disc is rubbing (it’s not though, it’s from the motor internals). Again, no big issue. My motor is the earlier square wave version with LS controller. I’ve found that the rotational resistance has reduced over time such that a reasonable spin of the wheel gives about 3 revolutions going forwards and about half that going backwards. The bike rolls OK when riding, though not surprisingly it doesn’t roll as freely as my mates Cannondale Slate gravel bike that I use a reference. I’ve also tried to find the limit in terms of hill climbing with this motor. My local challenge is Rose Hill in the Lickey Hills area of Birmingham. At it’s steepest it’s 1 in 8 (12.5%). There is no way I could ride up this without assistance. It managed OK, but speed was down to about 8 mph at the steepest point, but still not too bad considering a 90 kg rider. The motor temperature was fine (barely warm), but the controller got very hot, too hot to touch. Not sure what the max temp these controllers can run at, but I feel that I was pushing my luck a little. Ambient air temperature was 25 degrees C, and my controller is tucked away in a saddle bag with no ventilation. No real surprise it got so hot. I feel that this motor could take more current without doing any harm, but to be honest what I’d really value is just a little more speed. Mine is geared for 15.5 mph on a 700c wheel. I guess more speed would mean more volts, so new battery and a new controller required. Might save that thought for my next build...

Regarding reading Chinese, you can easily download the google translate app onto your phone. You point the phones camera at the Chinese text and you get a live translation on your screen. It’s not perfect but should give you an accurate enough translation to work out what goes where.

The black plastic controller box in the link is mounted to the vertical seat tube on the frame. They are a bit ugly but do the job. If you order the Xiongda kit from Bonnie, ask her to supply a controller box as well. Very cheap, just a few dollars.

I bought a 36v 11.6 aH pre-welded cell pack from ebay: https://www.ebay.co.uk/itm/E-bike-Battery-11600mAh-11-6Ah-36V-40x-Panasonic-NCR18650PF-10S4P/362282917089?hash=item5459be9ce1:g:Ru8AAOSw30Ralkzv Then I soldered on a BMS that was bought via Amazon and hoped for the best! It was actually pretty easy, but in hindsight there are plenty of 'softpack' 40 cell batteries with the BMS already included that would mount in the Topeak saddle bag. However, make sure you can actually mount this type of bag under your saddle with enough clearance to the rear tyre. Mine is pretty marginal and I have about 20mm clearance. If I did this again (which I might do for my wife) I'd probably use the bottle battery that d8veh has identified. Less weight, and only once have I needed all the range that a 40 cell 11.6 aH capacity offers (60 miles on a hilly route, and my back side was really hurting at that point!).

Hi Jens, I think your son will be OK getting 30km from a 7aH battery. Everyone will get a different result depending upon how much pedalling they do and how heavy they are, but based on my personal experience where I'm getting 50km from about 4aH of battery capacity, I think you will be fine.

I found the spec sheet for the Sanyo NCR GA cell which states a 10 amp max discharge current, so with 2 cells in parallel you can in theory draw a maximum of 20 amps. If your controller is rated at 12 amps then each cell would need to be capable of supplying 6 amps. Which these GA cells clearly can. The 6 amp discharge curve is shown in green in the chart below. The only thing to be aware of is 'voltage sag' where the supplied voltage will drop when large discharge currents are required. This might become an issue if you are going up a hill, pulling maximum current, when the battery is 75% discharged. The drop in voltage might trigger the controller cut off (which will be at about 31 volts), so you might have to ride around this using lower PAS settings as the battery depletes. What sort of range are you looking for?

The link suggests that the 7aH battery is in a 10S2P configuration? If so it suggests that the cells are 3500 mAh each which is pretty high, and the associated max discharge rate may be an issue. I'm not sure what the KT controller is rated at, but I suspect at least 12 amps at peak. Which means each cell needs to be able to deliver 6 amps. Do you know what type of cell is used in that battery?

Hi Jens, no problem. First thing to say is that I have no point of reference having never ridden an ebike before starting this build. But overall, it's a transformational change compared to riding unassisted! Firstly, the performance up hills is absolutely fine for me. I weigh 90kg and the converted bike weighs 16.5kg, so there is a fair bit of weight to pull up a hill. My normal routes are more long inclines, with a 3 mile constant climb of about 150 metres in height. So not too steep. Some short parts are much steeper, and it still climbs these OK and I don't think I'll find a hill that it won't manage. In terms of general riding, I now completely understand the point that d8veh made about the lag between pedal input and the reaction of the motor / controller. It feels like a 1 second delay which I soon got used to, but which also made me thankful that I installed a brake cut-off. Low speed manoeuvres, especially near to busy traffic junctions would be a bit worrisome without. I tend to ride with PAS assist set to 2 on the flat, and then use 3 or 4 on inclines. The range is quite impressive, with a 30 mile trip with 500m of altitude gain only using about 40% of my 11.6 aH battery. The battery is a 10S4P configuration made from Panasonic NCR18650PF's. Voltage at start of journey = 41.8v and at the end was down to 38.1v, and the voltage readout is clearly a better indicator than the 5 bar readout (which was just dropping from 5 to 4 at the end of a 30 mile trip). There is a bit of extra resistance running with no assistance (compared to the original non converted condition). That's no surprise as the bike weighs an extra 4.5kg and I increased the tyres from 38c to 47c (which also transforms the ride quality). In terms of speed, my controller and motor is set up for the UK legal 15.5 mph. Not surprisingly, it makes cruising at this speed on the flat much easier, whilst the effect of drag on higher speed downhill routes is negligible. So, overall I'm quite pleased. I wanted a small lightweight motor to add some assistance rather than an electric motorbike. I think you mentioned that your motor is a later version with hall sensors and a KT controller, which should make a nice difference in terms of response. I'd love to hear how you get on.

Hi Jonah, the YTW-06 that I'm using has a 12mm diameter axle with 10mm across flats. I simply filed out my quick release drop outs to a 10mm slot and made the slot deeper to get the axle back on centre line. But I had plenty of metal around the slot to play with, whereas your fork looks very narrow. I'm not sure if this is true, but I'm pretty sure that Panda ebikes are using the same motor in their swytch kit, and the order survey offered an option to match an 8 or 9mm quick release drop out (I've ordered one for my wife's bike). Maybe ask Bonnie at Xiongda if they can offer an axle diameter to match your fork? If you send her the same photo as in your original post then I'm sure she will see the issue. I doubt if they have made up and despatched your order yet.

The brake sensors are the standard generic stick on parts. I simply removed the 3M tape, turned the sensor body over 90 degrees to allow it to fit between the buttresses on the master cylinder, and epoxied in place.

The motor cable is secured to the fork at the same tie down point as the brake line, but there is quite a bit flapping around in the breeze. Thanks for the suggestion of using a Velcro strap. That's a great solution to still allow easy wheel removal for puncture repairs!

I've only done few miles on the bike since finishing it on Friday night (the weekend snow seems to have dissuaded me!) so can't really say how it deals with hills. I'll try a little harder this weekend and let you know. I didn't know that Xiongda offered a 48v version. Is this the same motor but running a different controller, or are the windings different? Incidentally, I think another forum member has recently ordered an updated version that includes hall sensors. My motor was built in November, and pretty sure it is sensorless. A couple of pictures of the end product...

Hi awol, yes the battery is in the bag along with the controller. I know what you mean about the height required to fit this bag, and I only just managed it with about 30mm clearance to the rear tyre. Which raises a question about how waterproof these bags are. I imagine it will collect quite a bit of water from the rear tyre and I'm slightly concerned about the controller and connections. Still need to think some more about that.

Hello Everyone, I’ve lurked here for a few months, reading many threads about various conversions in order to help plan my own build. Having now finished it, I thought I’d post the results on the basis it might be informative for others. The donor bike is a Norco Indie 3 (2014) which has covered about 1500 miles. It’s a hybrid style bike with flat bars and 700C tyres. My normal fun ride is roughly 30 miles round trip, but miles 24 to 28 are a fairly constant incline that detracts from the pleasure of the rest of the ride. My thoughts were that a lightweight hub motor could be used to aid on the inclines without detracting from the normal pedal power on flatter sections (so a primary concern was not to add too much weight). Inspired by threads written by d8veh and AWOL, I decided to go with the small Xiongda YTW-06 as a front hub conversion. I've taken a few photos of the build which I can post if I can work out how to! The finished article appears as my avatar. The bike weighed 12.1kg before I started, and the finished conversion came in at 16.5kg all up with a 36v 10S4P 11.6 Ah battery. Total cost excluding the donor bike worked out at £358 which I don't think is too bad.