Cargo Bike Conversion Advice

EXE Bikes

Pedelecer
Jun 7, 2023
35
1
Hi everyone.

I am new to the site and have spent several weeks collecting information about what the most suitable conversion kit will be for a new cargo bike build.

I recently test rode a Tongsheng 500w and a Baffang 750w and as the owner of other Bosch systems much preferred the Tongsheng with its torque sensing.

However, I am concerned with reports of Tongshengs reliability issues (even the new B model) and happy to go with the Baffang if that is the better long term option.

I won't be using assist all the time, only on the steep grades when fully loaded (kids or shopping). I live in a hilly part of Devon.

The bike uses 24inch wheels so I am a bit limited on hub motors such as Dillenger, who have said theirs is not suitable. I suppose I could get a motor and build a front wheel as would distribute the weight.

What is the tried and tested route here, I am mostly on towpaths and cycleways so not looking for a 250w road legal system as I think I need the extra watts (torque) for pulling power.

Any help would be greatly appreciated.

Karl
 

Woosh

Trade Member
May 19, 2012
21,639
17,440
Southend on Sea
wooshbikes.co.uk
Hi Karl,

If you go for a rear hub motor, you will need a high torque motor like my 48V DWG22C.
You will have to relace it to a 36H 24" rim to suit your cargo bike.
The hub motor's flanges are drilled for 12 gauge spokes. 14 gauge spokes are thinner and more flexible so usually preferred for home lacing, so you end up with a wheel that may feel a little twitchy.
https://wooshbikes.co.uk/?hubkits#dwg22c-48v-kit
what kind of brakes have you at the rear?
 

EXE Bikes

Pedelecer
Jun 7, 2023
35
1
Hi.

I just emailed you via your site so ignore that when you see it.

6 bolt discs on the rear.

I have not relaced a wheel before, can you do this or would it be a LBS job?

Thanks

Karl
 

Woosh

Trade Member
May 19, 2012
21,639
17,440
Southend on Sea
wooshbikes.co.uk
rear disk brakes:
The DWG22C needs 180mm rotor. How big is your rotor?

I have not relaced a wheel before, can you do this or would it be a LBS job?
It's a skilled job but not difficult. You can learn to lace a wheel with Youtube video in about 2 hours. Getting an LBS to do that for you will probably cost about £70 + the cost of the spokes.

 

EXE Bikes

Pedelecer
Jun 7, 2023
35
1
Ok ideal.

Yes they are 180mm rotors.

I will have a watch of the video and speak to a mate with a truing wheel and get back to you.

So I am assuming you wouldn't recommend a mod drive such as a 500w baffang or Tongsheng?

Thanks for your help.
 

Woosh

Trade Member
May 19, 2012
21,639
17,440
Southend on Sea
wooshbikes.co.uk
all motors have tradeoffs. Crank drives put a lot of tension on the chain, making gear shifting very difficult. If you fit a shift sensor, it loses power mid shift so going uphill can be a struggle.
For cargo bikes, the DWG22C on a 24" rear hub is a very good choice. It will give you excellent torque in the range of 6mph-14mph without straining the gears and chain.
 

soundwave

Esteemed Pedelecer
May 23, 2015
17,992
6,733
a mid drive will have more power and will be better for hills and the bafangs are pretty much bomb proof and you can buy all the parts needed to service them.

you can also use 3rd party controllers if you want more than 30a controller limit but the batt must be capable of this discharge rate or kaboom ;)
 

soundwave

Esteemed Pedelecer
May 23, 2015
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all motors have tradeoffs. Crank drives put a lot of tension on the chain, making gear shifting very difficult. If you fit a shift sensor, it loses power mid shift so going uphill can be a struggle.
For cargo bikes, the DWG22C on a 24" rear hub is a very good choice. It will give you excellent torque in the range of 6mph-14mph without straining the gears and chain.
i have a eagle axs mech on my haibike and have turned on multi shift and shift under power going 30mph+ and its not fell off yet :p

all i have to do is push a button and it goes up and down all gears in seconds so way better than a cable but it was 500 quid:rolleyes:
 

guerney

Esteemed Pedelecer
Sep 7, 2021
12,235
3,411
My 250W Bafang BBS01B converted 20" wheeled folding bike hauls trailers up steep hills great. I haven't needed to increase the controller amp limit beyond it's stock 15A.

 

Woosh

Trade Member
May 19, 2012
21,639
17,440
Southend on Sea
wooshbikes.co.uk
i have a eagle axs mech on my haibike and have turned on multi shift and shift under power going 30mph+ and its not fell off yet :p

all i have to do is push a button and it goes up and down all gears in seconds so way better than a cable but it was 500 quid:rolleyes:
your bike has torque sensor and weighs what? 21-22kgs and you weigh? 60kgs? shifting gears on AXS takes a tenth of a second. It's not the same when you have a 200kg-250kg cargo bike on a cadence sensored crank drive shifting an Acera derailleur.
The gearshift sensor on the BBBSes turns off the power for more than one second. On a hill, that makes a big difference.
Anyway, your chain would pop on a cargo bike.
 

guerney

Esteemed Pedelecer
Sep 7, 2021
12,235
3,411
The gearshift sensor on the BBBSes turns off the power for more than one second. On a hill, that makes a big difference.
On my bike at least, there is no issue whatseover - gear changes are as smooth and timing works as well as when not hauling. Except in wet weather, and only on hills.
 

soundwave

Esteemed Pedelecer
May 23, 2015
17,992
6,733
then put a throttle on it :p it has 2 year warranty so trying to brake it ;)

my bike is just under 24kg 10 years old and only on my 2nd cassette and change chain at 0.5 and have over 1500 miles on the chain atm but is not far off 0.5 now.
 
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guerney

Esteemed Pedelecer
Sep 7, 2021
12,235
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Another positive experience of the gear sensor. I'm not the only one after all:

 

soundwave

Esteemed Pedelecer
May 23, 2015
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how my m8 with his hd at 30a has never broken a chain idk but he wont buy anything over 9spd ;)
 

Woosh

Trade Member
May 19, 2012
21,639
17,440
Southend on Sea
wooshbikes.co.uk
On my bike at least, there is no issue whatseover - gear changes are as smooth and timing works as well as when not hauling. Except in wet weather, and only on hills.
Denwyn bought secondhand one of my CD bikes in 2013. Back then, there was no gear sensor. He lives in Somerset where hills are everywhere. He sold it in 2016 and bought a Wisper.

I started to fit gear sensor to the Woosh Krieger in 2016 after he sold his.


 

Woosh

Trade Member
May 19, 2012
21,639
17,440
Southend on Sea
wooshbikes.co.uk
then put a throttle on it :p it has 2 year warranty so trying to brake it ;)

my bike is just under 24kg 10 years old and only on my 2nd cassette and change chain at 0.5 and have over 1500 miles on the chain atm but is not far off 0.5 now.
with a rear hub kit, you can still ride after you break your chain ;)
 
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EXE Bikes

Pedelecer
Jun 7, 2023
35
1
@soundwave and @guerney out of interest what versions of the Baffang are you using?

I see the point of extra wear on the drivetrain. On the bike I test rode it had a manual cut off button to press whilst changing hear under heavy loads, was a bit of a faff tbh.

I suppose the gear shift sensor would solve that.

@Woosh I have enquired with a local wheel builder about switching hubs, will get back to you.
 

soundwave

Esteemed Pedelecer
May 23, 2015
17,992
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on my bike with the cable mech i had to get used to how it cuts power and when to change gear as when my right leg is at 12 o clock if i change then it goes bang bang bang but if i get to 9 0clock just b4 i pump power in its as smooth as butter and why i get so much mileage out of my chains and keep it clean as possible.


and at that price in these times there on crack :oops:
 

guerney

Esteemed Pedelecer
Sep 7, 2021
12,235
3,411
I covered both ends of the sensor with self-amalgamating rubber tape, to keep water and dust out - doing so makes it looks a little less tidy. I can see why the gear sensor is left out of kit bundles, as it not operating perfectly could spoil an otherwise largely problem free and easy installation.
 
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soundwave

Esteemed Pedelecer
May 23, 2015
17,992
6,733
i have a haibike with a bosch cx motor custom built buy ebike motor centre uk but m8 has hd bafangs hd and uses it to go to work every day in all weathers and in over 2 years its still going but needs a service and new bearings as makes a noise.