cargo bike conversion

[himupstairs]

Hello,

I'm new on here, and came to get some advice for a conversion I'm considering.

We have a gazelle cabby cargo bike that would benefit from some assistance, but I'm wondering what i should be looking for. Currently I'm thinking of a UK road legal 250w Bafang mid drive with as much battery as I can get. I've looked at a few other mid drive kits but due to the shape of the frame around the BB I think the Bafang is the only one that will fit.

I also found a dutch place that has done the conversion and it looks very neat: https://fon.bike/voorbeelden-van-omgebouwde-fietsen/gazelle-elektrisch-maken/gazelle-cabby-met-bafang-middenmotor-ombouwset/

Does anyone have experience of these kits on a bike that weighs about 40kg before anyone sits on or in it, and likely upwards of about 130-140kg typically when loaded, and will be used around a fairly hilly city? Is there anything else I should consider?

Cheers

 

[Nealh]

The legal unit that comes to mind with oomph is the BBS01ETM/ MM G340 250 model that has a 25a controller and uprated internals for extra torque. I have only seen it available from Brighton ebikes.

 

[himupstairs]

Thanks, the ETM model looks interesting.

Has anyone had any problems with the motor rotating when using the Bafang kits? The absence of a stabilising connection back to the frame concerns me a bit - I've noticed the tongsheng kits have a mounting system that uses the chainstays to stabilise the motor.

Also, am I right in thinking that the brake sensors act as kill switches when used in conjunction with a throttle? Would I need the brake sensors if I wasn't installing the thumb throttle?

cheers

 

[vfr400]

The Bafang motor grips the bottom bracket tube and uses friction to resist the torque. It's fine as long as you don't have a press-fit bottom bracket. Also, it's no problem to add a tie-bar to the bracket or its fixing screws on the left side of the motor.

 

[Surf_Wonder]

The Channel "ebike commuter"

helped me out ALOT.

In the end I went for a 48V 500w rear wheel on my bike because my bike is normally hauling something, so of course I don't go at wild, I have lots of crazy inclines so - my top "I'm in control" speed is a whopping 20km ph (ebike commuter has a 250w system), and I made my 500w decision after this change in Northern Ireland https://www.pedelecs.co.uk/northern-ireland-scraps-electric-bike-registration-and-license-requirements/ so I'm expecting the U.K law to follow suit, I installed a pedal assist system , I don't have my throttle installed/attached, my battery/batteries are not VISIBLE.

My batteries are 2 x 48v 10ah with a parallel connector as my average round trip commutes are 8miles without my trailer so, I then only bring and use 1 battery if , the batteries are connected and used in parrallel if my commute is going to be over 20km or if I'm fully loaded with my trailer.

I ran into EVERYTHING mentioned in videos

&

and I bought and chopped a rear axle wheel spacer that was for Dirt/Stomp

- that was a want, not a need that I removed the nuts that was acting like a spacer (nut and locking nut).

A picture of my fully loaded e bike n trailer build is below.

Good luck with your project

 

[ph1]

Hello Himupstairs

I was wondering if you had made the conversion and how it went?



I currently live in a very flat area but are moving to a more hilly one and and thinking about converting our Gazelle Cabby cargo bike (two wheel, nexus hub gear, nexus roller brakes, 26" rear wheel, 20" front) .

In a similar/the same way I am looking for something that will:
Cope with a heavy bike + adult + child
Applies power in a natural way (no throttle)
Can be fitted to a cabby.
EU/Swiss legal.

If anyone has other suggestions I am very open to them. I think that it will be limited to mid drive and front wheel drive as there is no gear hanger etc. as the bike has an internal hub gear.

I am a little worried about A) the brakes, Cabbies have drum breaks the early editions (ours) dont have very powerful ones, I don't know if I should upgrade to later ones or get a disk break mount fitted to the front forks and B) how the Nexus gear hub holds up with the extra power over time (for a mid drive system). Again any information would be welcome.

Thank you

 

[Scorpio]

Hi @ph1 do you have a photo of your bike? One option to upgrade your brakes, I recently bought new suspension forks for a disk brake conversion for £25 from bankrupt-bike-parts (look on ebay or amazon) https://www.ebay.co.uk/sch/Forks/177815/m.html?ssPageName=STRK:MEFSXS:MESOI&_ssn=bankrupt_bike_parts
Most (all?) front wheel drive wheels include fittings for a disk brake, you would then need to find a brake disk and a caliper / lever kit (prices range from budget cable operated version to big name hydraulic).

 

[ph1]

Thanks for the reply.




You can see the tiller which comes from the handlebar tube behind the box, under the box and attaches to the top of the forks. So unfortunately replacing the forks with a set that already has disk mounts would not be an option as you would then need to weld on the tiller mount.

This is the current front wheel brake mount and the underside of the bottom bracket which is very flat .

 

[Scorpio]

The bike looks very useful, I had an idea of the front forks but wasn't sure about the details.
I have a similar hub brake on one of my bikes it works (sort-of) but I understand why you would like to upgrade it.
Hopefully somebody else can think of a solution, and make the project work for you

 

[himupstairs]

Hi,

I've just received a bafang middrive kit from woosh, but have not yet fitted it. The only thing i need to sort out is a sleeve for the bottom bracket, and probably a new chainguard. The frame has a traditional style press fit bottom bracket with a shell of (i think) 40mm. Fortunately i have a friend with a lathe to get a spacer made to get it to the standard BB size. It will be EU road legal once done (250w, assist only, cut out at 25km/h).

Our Cabby has the better shimano hub brakes, which are just about ok most of the time - I regularly carry a full load of shopping, and sometimes 2 kids. We live in Edinburgh and parts of town are reasonably hilly. I have always been tempted to get a disk mount added to the fork though, or find some other way of improving the braking.

Gazelle have just brought out a new e-cargo bike with disk brakes. I'm going to have a look at one of them and see if I can get some of the forks to fit to my cabby, as the steering linkage looks very similar.

I'll post back on here once I've got the kit up and running.

 

[himupstairs]

To update this, I got the bafang mid drive kit all fitted up a week or so ago. The only tricky bit was adjusting the nylon bottom bracket cups of the existing BB to accommodate the bafang unit.

I had planned to use a rack mount battery, but availability meant I went with a frame mount instead. This required extending the battery wiring by a small amount, but that wasn't a big deal.

It all works well, and obviously makes cycling the Cabby much much easier! Still considering a front brake upgrade though.

I'll take some photos when it's not raining and put them up.

 

[Scorpio]

@ph1 etc, it looks like you can get bolt-on kits to convert bikes so disk brakes can be used. I have no experience but it might be an option for you. Eg https://www.snapdeal.com/product/adjustable-bicycle-bike-disc-brake/669072189715

 

[stumpedinoz]

Hi himupstairs. I have a Gazelle Cabby and a Bafang BBS02 mid drive unit. I have run into trouble trying to remove the original bottom bracket. It seems to be a unique press fit design that I haven't seen before. I've only ever seen square taper as a threaded interface. Can you tell me how to go about removing this bottom bracket? Thanks, John.

 

[Deleted member 33385]

The legal unit that comes to mind with oomph is the BBS01ETM/ MM G340 250 model that has a 25a controller and uprated internals for extra torque. I have only seen it available from Brighton ebikes.

I wish I had seen that before I bought my BBS01b nealh! But I had no idea this forum existed till Dec. Are your bees excited by the warmer weather?

 

[himupstairs]

Hi himupstairs. I have a Gazelle Cabby and a Bafang BBS02 mid drive unit. I have run into trouble trying to remove the original bottom bracket. It seems to be a unique press fit design that I haven't seen before. I've only ever seen square taper as a threaded interface. Can you tell me how to go about removing this bottom bracket? Thanks, John.

Hi John,

The bottom bracket should come out fairly easily. It's a cartridge with two separate nylon cups that push into the BB shell. Mine was all pretty well greased so easily removed from the frame.

Once I had the cranks off, I tapped the end of the BB axle with a soft faced mallet and it came right out with one of the nylon cups. You can then get the other cup out easily.

The BB shell is not a standard size, but I reused the nylon cups by getting them cut down on a lathe to effectively make an adaptor that could accommodate the bafang BB.

I hope that makes sense and is helpful.

Eck

 

[himupstairs]

While I'm here, can anybody offer chainring advice for the Bafang BBS01? I could do with improving the chainline on my Cabby conversion, but haven't been able to find any chainrings with much more than the standard offset. I've looked at lekkie and precialps, but the chainrings that have bigger offset are for the BBSHD, and evidently won't fit the BBS01.

Any ideas?

 

[stumpedinoz]

Thanks everyone. Success. I just had to be more firm with the hammer. Motor is on and functioning well.

Chainline is a little wide but within limits. For a chainring smaller than 44 there can't be much offset inboard as the diamter of the chainring is smaller than the diameter of the drive mechanism. At least on my BBS02 it is.

Some of the chainline issue is due to the bottom bracket shell being wider than the specified 68mm that the Bafang motor is designed around. So you could face the shell down to a narrower width to bring the motor back towards the midline of the bike and achieve a narrower chainline.

But then you can't reinstall the original cranks and bottom bracket. So I'm just leaving it as it works without issue.

 

[himupstairs]

I'd rather the chainline was a bit straighter, but it works ok as is - I'll probably leave it for the time being.
I did also consider facing the BB shell but as you say, the original bits would then not fit, and it all works ok anyway.

 

[viellen]

I was wondering if you have any updated pics of your bike with the bafang and battery installed? I also have a Gazelle Cabby and purchased a different mid-drive kit for it (TSDZ2) and the local bike shop is saying they can't figure out how to clamp it to the bike and that there's no place to mount a battery. I'd love to see how you did yours.

 

[stumpedinoz]

The Tongsheng TSDZ2 looks similar to the Bafang BBS02 install. Just slide the motor through the bottom bracket shell, install the bracing plate and lockring on the non-drive side and you're done. As the shell width is 70mm not 68mm you'll need 2mm of washers between the bracing plate and the motor. When you do up the lockring it presses the serrations of the bracing plate into the non-drive side of the bottom bracket shell. That is the mechanism for clamping. The Bafang uses a dual lockring design which means the thread on the motor is a little longer. That allows for the 2mm extra width of the bottom bracket shell. The Tongsheng looks like a single lock ring with shorter thread so hopefully there's enough purchase to allow the install.

Battery mount woodscrewed into floor of bucket. Could mount sideways under seat but would prohibit folding of bucket.


Battery cable runs out back of bucket. Cabling runs up steering mast and wrapped around brake cables.


Cabling running under frame cable tied to gear cable


Chainline is a little wide but no issues so far.


Installation in bottom bracket shell. Note 2mm silver washers between brace plate and motor.