Ebike Conversions and towing child trailer

webbierwrex

Finding my (electric) wheels
Sep 28, 2020
5
0
Hi,

I am new here and new to the world of ebikes. My partner and I are expecting our first child in November and as a carless house transport will become more difficult. We are hoping to get a bike trailer that can be swapped between either of our bikes as well as fitting her bike with some sort of assistance.

The problem is, I don't really know where to start. I have seen so many kits and options with prices ranging from £300-1000+ and I don't really have a clear idea of what the difference is.

I have seen mention of Whoosh and some of their kits look reasonable value compared to the Amazon/Ebay route. Are there any others to consider? Any good recommendations?

Ideally, the motor would be a cheaper one, and it doesn't need to be very powerful or have a huge range as it's only to give a helping hand and for very flat around town cycling.

Is there anything else we need to consider regarding the trailer too? Will this necessitate going to a higher watt motor, for example? Is a front or rear wheel motor any more or less suited to being used with a trailer?

Thanks in advance!
 

Woosh

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May 19, 2012
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Southend on Sea
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Please post a picture of the donor bike and take it from there.
 
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Nealh

Esteemed Pedelecer
Aug 7, 2014
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Be careful when you say cheaper one.
For instance on ebay/amazon you will see cheap 250w/1kw dual hubs and 500 or 1000w hubs, these are Black,large and heavy about 5kg. Known as direct drive hubs not really suitable for towing let alone for most generic uses for bikes.
 
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Woosh

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May 19, 2012
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that's a straightforward bike to convert. You can have front, middle or rear motor. You can have a downtube battery or a rack battery.
Do you have any preference?
I suppose you start with a child seat?
 

webbierwrex

Finding my (electric) wheels
Sep 28, 2020
5
0
A slight preference for wheel but only as I'm under the impression it would be easier to fit and more discrete. Battery would only need to be small but no real preference.

Is a front or rear wheel better? How about if pulling a trailer?

We dont have any child seats or trailers yet, we have only just started looking in to them but both are an option.

Thanks for replies!
 

Woosh

Trade Member
May 19, 2012
14,987
12,266
Southend on Sea
wooshbikes.co.uk
Is a front or rear wheel better? How about if pulling a trailer?
Rear hub motor or middle motor.

First some issues with fitting a hub motor:
if your front wheel has a quick release skewer, the jaws opening is 9mm wide because they are made for 8mm skewers. The axle of hub motors measures 10mm x 12mm so you will need to widen the jaws from 9mm to 10mm and deepen the opening a little bit, about 1mm-1.5mm. I usually do that with a half round file then deepen with a 10mm round file. That does not take long to do, about 5-10 minutes.
If you fit a rear motor, most often the jaws are 10mm wide, so a bit easier to drop the wheel in but you will have to remove the old cassette and refit it to the new wheel. You will need a cassette removal tool and a chain whip. Again, this takes about 10 minutes. So overall, fitting a front hub kit or a rear hub kit takes about the same time.
Issues with fitting a middle motor:
In principle, you only need to remove the bottom bracket, then slot in the motor and install the two M33 lock nuts. Sometimes, the frame welders leave a bit of excess weld behind. That will be something that happens maybe in one in five cases. You will have to sand off the excess weld before the motor can be slid in. If you have a dremel, then the job of smoothing the weld would take 15 minutes. Much longer with just sand paper.

Fitting the trailer.
You will need to install a trailer hitch onto the rear wheel axle.
If you have a rear hub motor:
The hitch has a 10mm hole but your motor's axle is 10mm x 12mm so you will need to deepen the hole on the hitch with a round file.
I use a 12mm carbide drill bit to enlarge the hole on the hitch.
 

Benjahmin

Esteemed Pedelecer
Nov 10, 2014
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I would recomend a geared rear hub. Front hubs can be a bit skittish on wet/loose surfaces and steering compromised in low speed manouvering. Nothing a regular cyclist can't handle, but with a child on board.......
Mid drives, because they give power through tha chain/gearset, are a bit more of a technical ride. You have to be in the right gear and cadence for the motor at all times.
Rear hub, weight is over the motor, doesn't care what gear you're in and pretty much bullet proof. Might be some small faff centrlising the wheel during fitting, but once done should be plug and play.
As suggested, put up some photo's of the bike including close shots of bottom bracket area and rear wheel fixing/gears.
You'll get all the advice you need to become a kit fitting hero !
 

Nealh

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Aug 7, 2014
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WIth flat terrain and no hills if towing a trailer, tbh honest any method of motor will be ok. If using a child seat/ carry on the bike then opt for the hub over a mid drive for your needs.

One needs to decide on which child carrying method is to be used, set the bike up first for the method required then carry out the conversion.
 

sjpt

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Jun 8, 2018
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You may well use a trailer at some point but also want a child seat at some point. If that is possible I would avoid a rack battery which could be awkward with a child seat for fitting and weight distribution.

We went through a variety of of things as our two children grew; some might be frowned upon today. I'm pleased to say they didn't put them off cycling. Cot on rear rack when our son was just under a week old; crossbar seat (son) on tandem (wife and I) with Hann trailer (daughter), converted double trailer (no custom child trailers then). The trailer was attached to the seat post; that was very convenient for quick hitch/unhitch but I think the now commoner rear axle or chain stay mounts are better. We didn't go electric till 40 years later.
 

webbierwrex

Finding my (electric) wheels
Sep 28, 2020
5
0

here are photos of the bike. I measured the front drop outs and I don't particularly fancy filing material away so am now leaning towards a rear-wheel motor. It's an 8-speed cassette and we have the tools experience to handle that very easily.
I don't think there is enough space in the frame to mount a battery as the bottle cages are on the lower of the two cross bars, it might, but it would be tight and I suspect not. Which means pannier battery.

We haven't yet decided exactly what child carrying solution works best for us. We like the idea of having a a bike trailer if it allows more mobility from a younger age, otherwise the more 'bike like feel' of a child seat on the back might take priority. However there is also the question of transport when you get to your destination (around town, for example) where a trailer/stroller convertible might be useful.

So, any recommendations for rear wheel motors that fit the bill? From my research, it looks to be between Whoosh (thanks for the help so far) and cyclotricity which currently have a sale on.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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Cyclotricity stuff is dual power, illegal. Although they use KT stuff it is customised so generic KT controllers/ lcd's don't work. One is then tied to their prices.
 
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Woosh

Trade Member
May 19, 2012
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I don't have anything in stock except BBS01 kits until the next shipment arrives (25-October).
 

Benjahmin

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Unless a battery is fitted to the top tube (restricting step through) then it'll have to be a rack battery. However said rack would probably mount further forward than your existing. There are some frame batteries that mount from the side, so may allow fitting between the frame tubes.
Could consider a soft pack battery in a pannier (to get the weight lower) but they do suffer from being jiggled around and are heavy on pannier wear. I've wrapped my second battery in a layer of half inch high density foam to protect it and seems OK. But the pannier is starting to show stress tears, after around 3k miles.
 

harrys

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Dec 1, 2016
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I briefly towed my grand daughter with a BBS02 on an old mountain bike. With the mid drive, I didn't have to worry about drilling out the hitch hole, or having the assenbly causing my hubmotor to come loose.

On flat ground, there is so little resistance that I got a second mirror to point at the trailer to make sure it was still there. Anyway, grandpa always went first and grandma followed.

The last twelve months, we've used a hitchhiker rig on the back, but she now rides her own bike. I'm toying with the idea of a low power front drive 20". Lots of kids younger than her are scooting around my neighborhood unsupervised on plastic electic motorbikes.
 

Surf_Wonder

Finding my (electric) wheels
Jul 15, 2020
9
1
With regards to my conversion, there's only been one channel that addressed all the issues I ran into
and part 2
.

Also, I had to use a step drill to enlarge the hole my trailer hitch but I'm ecstatic at my end results because you can't see my control box or batteries unless you inspect very closely, my ebike does not look like a conversion at first glance and I've been complemented everytime I've arrived at a campsite or beach :) .

Designing and converting's been fun so I hope you get to enjoy the task as much as I did :)
 

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