Brompton Nano or Kudos Secret?

[Deleted member 4366]

You can fit a rear motor to any Dahon apart from that new one they had at The Cycle Show with 16" wheels that folded as small as a Brompton.
Here's an idea of what's involved:
http://www.pedelecs.co.uk/forum/electric-bicycles/10584-electric2011-dahon-jetstream-p8.html
missing photos here in reverse order:
Dahon Photos by d8veh | Photobucket
You can now get the Q100 already built into a wheel with the cassette version motor, so you can use your existing gears and you can get in-line brake sensors, so you can keep your existing brakes. You can get everything you need from BMSBattery for a very simple conversion that should only take a few hours to do.
Q100C CST 36V350W Rear Driving E-Bike Motor Wheel - BMSBATTERY

Edit: Note that the motor in this kit is 201 rpm which is too slow for a20" wheel, although they do the 328rpm single motor, so ask if you want the high speed one built into a rim.

 

[Kudoscycles]

Cricket....the next batch of Secret bikes are due about November end....we have managed to keep twist grip throttle on these bikes....a throttle is becoming something of a rarity on these bikes because they are not allowed in Europe and that is the biggest market.
You could try the bike on the 44T and if you feel the need change it to a 52T later,any bike shop could easily make the change-personally I think you will be very happy with the 44T,I don't find my legs going round like a propeller and anyway you said that for health reasons you would use the throttle a lot-if that is the case an 8 Ah battery and 36v are essential.
Where are you located?

 

[Cricket]

Hi KudosDave - I think you are right about the 44T. I'm currently located in the Hampshire/Surrey area.

 

[jhruk]

Jhruk - did you buy your Dahon 20" already converted or DIY? I really like the look of some Dahons but could never consider fitting a motor myself. However, my partner is itching to try. If you did do it yourself could you tell me which 20" Dahons it's possible to do this with and where you buy the conversion kits? Thanks

I already had the Dahon and converted it with this this kit from BMS Battery. It was very straightforward and was mostly completed in an afternoon. The choice of front wheel drive was dictated by the bike having Sram Dual Drive gearing, which uses a hub gear and derailleur. This thread has more details. As d8veh says you should be able to convert most Dahons, or the similar Terns.

If you want to buy ready converted C H White do several front wheel drive ones and Cyclezee do a rear wheel drive.

My favorite small wheeled folder for the type of use you describe would have to be the Birdy. For various reasons I wouldn’t buy their own electric version and unfortunately I haven’t gotten around to converting one myself yet so can’t give you much help with that.

 

[Kudoscycles]

Hi KudosDave - I think you are right about the 44T. I'm currently located in the Hampshire/Surrey area.

Is West London too far for you?.....we have a new dealer in Hampton Wick,Kingston,the London Electric Bike Company,he has 30 plus e-bikes in stock including the Secret model,there is Bushy Park only 200 yards away for an easy test ride,pick a nice day it's a nice part of the world for a bike ride.....next door is Sigma Sport,a beautiful bike shop,very interesting just to look round.
LEBC.....25 High Street,Hampton Wick,KIngston,07841 412199,they are open every day except Tuesday and Sunday.
Hope that helps
KudosDave

 

[Cricket]

How funny, used to live in that part of the world and Bushy Park was our old stomping ground so I know it well. It's a possibility so will bear it in mind. In all honesty am thinking it will be another few months till I'm well enough to sit on a bike (which is why I've just started looking/researching) so am thinking it'll be after Xmas or spring before I actually get one. There's no point in it sitting in our damp garage all winter either. But thanks for letting me know - the Secret does seem like a good bet.

 

[Cricket]

Thanks to everyone so far who has helped me choose which bike to purchase. After a bit of deliberation and some hill climbing advice yesterday (much appreciated) I've narrowed it down to a 20" folder such as Volt Metro/Wisper/Kudos Secret/Juicy. Look forward to trying them out. It suits me to buy a ready made bike.

However, my partner is still itching to have a go at a conversion. We may well buy one and convert another so we have one each. It might be better if he joins the forum as I am not technically minded but in the meantime can I ask those of you in the know a few questions? Not sure if I should start a new thread elsewhere for this.

Evans have some ex demo bikes such as the Tern Link D8 and the P9. Are either of these bikes suitable for (a very easy!) rear conversion? Is one easier to convert than the other?

They weigh about the same as a Brompton M3L (11.5kg) so what can we expect it to weigh with a rear motor, throttle etc...incl or excl the battery?

Are the small hobby batteries such as zippy suitable for this purpose? I see some people mention using two - is one a spare or are they both connected?

The conversion must be stealthy with the batteries hidden in a frog or small pannier bag.

Roughly how much would the equipment cost (excl the bike)?

And finally is it possible without any cutting or soldering? Is it a case of slot the motor in and connect a few cables ?

Thank you, it's all a bit confusing for those of us new to these things.

 

[Cricket]

Oh yes, and would like to stick to the legal limits in the UK

 

[Deleted member 4366]

If you're going to convert a bike, you'd be better off getting a nice used one from Ebay. Most good quality folding bikes have narrow forks, so you need a rear motor, but most rear motors have the thread for free-wheel gears, which brings a whole load of gearing problems. That leaves very few motor options. I'm just about to try the Cute Q100C from BMSBattery. I already have the normal Q100 on my Dahon, but I want to restore the gearing to 8 speed. The Q100C has the spline for cassette gears, but I'm not sure yet if the overall width is OK because the Dahon frame is very stiff, but I think it should be OK.

The weight of a complete kit with a 10aH frog battery would be about 5kg added to your bike, so 17kg overall should be possible.

R/C batteries are OK if you know how to manage them. From your questions, I'd say that they're unsuitable for you. There's not much advantage from them if you want to stick to legal speeds, but they become a good option if you want to go faster.

A kit with battery from China is about £400 including duty.

There's always a bit of fiddling about with the stuff from China. Most of the things just plug in, but it's common to have to solder a connector or two and adjust the spokes in the wheel. There are some kits that are more plug-and-play, but I don't know of any decent ones for decent 20"-wheeled bikes.

Keyde also do a nice kit that's very easy to fit, but it has no throttle, and there's a few rumours of reliability problems.

 

[Cricket]

OK, I can get my head around most of that except for the gears but will pass the info on to OH in the hope he comprehends better than I. Would a one or no gear bike be better i.e. easier to fit and how would that affect the performance? My partner is looking for it to run on a par with the bikes I'm looking to purchase (mentioned above).

Not as lightweight as hoped. Surprising how much the kits weigh. What about the kits from the UK that people post links to on here e.g. Ezee? They are pricey though.

These are the sort of bikes he's thinking of (yes second hand ebay maybe)...

Tern Link P9 2013 Folding Bike | Evans Cycles

Tern Link D8 2012 Folding Bike (Soiled) | Evans Cycles

 

[Deleted member 4366]

the Ezee kit is powerful, but heavy. They have free-wheel gears, so you need a 7 speed DNP gearset as well (about £25 to £35), and that'll mess up your gear-change system. It'll probably be OK on the 8 speed, but you'd need a new changer on the 9 speed. As far as I know, all UK kits have the same problem. Most are front-wheel kits that won't fit because of the narrow forks that can't be widened (easily).

One other option is a crank-drive kit like the Bafang BSS01, but, like always, nothing is simple. You'd need one with a chainwheel of at least 44 teeth for comfortable pedalling. They're very easy to fit on most bikes, but I'm not sure about the Terns because the frame is different at the bottom. Cyclezee sells them, so he should be able to tell you if they're OK.

 

[Cricket]

Does sound a bit complicated. There was a 7 speed Tern (C7 I think) so are you saying that would be better?

I have just seen the Juicy Bikes conversion kit - seems more reasonable but is 8kgs?

Will have to speak to the kit suppliers and see if they can help too.

 

[JuicyBike]

I have just seen the Juicy Bikes conversion kit - seems more reasonable but is 8kgs?

Must get around to weighing that kit precisely, but note the weight includes everything - wheel, tyre, controller, levers, nuts etc etc. So much to do...

 

[Cricket]

Hi Bob,

That's not so bad if it includes the tyre. And the battery I assume?

Would it work with a 20" wheel folder? Is it rear or front wheel? And is it easier with any particular amount of gears/speeds?

It's all Greek to me really but thanks...

 

[Deleted member 4366]

I'll save you the trouble, Bob.
Motor 3.3 kg
Battery and mount about 4.5 kg
Controller and sensors about 0.5 kg

Total about 8.3kg.

I under-estimated the weight of the battery in a previous post because I forgot about the weight of the mount. The Q100C kit would therefore be about 7.2kg.

These figures are how much you need to add to the weight of an existing bike to get its new total weight, not the complete weight of the kit.

 

[Cricket]

Thanks d8veh, that is helpful.

Would still like to check on whether it is a rear or front wheel motor and what sort of bike speeds it would best suit.

OH sitting next to me looking pleased that you just swap the wheel. He thought he was going to be stripping the bike down completely and off searching for parts to make it fit!

 

[shemozzle999]

Hi Cricket,

Regarding a Tern/Dahon electric conversion with a Bafang Mid drive I have looked extensively into it and have concluded it would only be acceptable with the bespoke Bafang 52T chainwheel.

Unfortunately these are not currently available from Bafang at present but are listed as an option for future production.

The bottom bracket appears to be the standard size on both models so should not present a problem to fitting the kit, see blog:

Hands On Bike: Guide to Upgrading your Dahon / Tern Folding Bike

The smallest wheeled model which would accept the current kit and give reasonable speed would be the newly announced 24" Tern Node.

p.s. I can get 2 folded Bromptons on the back seat of a 4 door Aygo but not even one in the boot without dropping the rear seats, it is too tall.

 

[trex]

the small wheels of the folding bikes will garantee good climbing ability - I can't see why you would want crank drive?

 

[Cricket]

This definitely seems a bit complex for me and OH looks a bit lost too. This leads me to the conclusion that we should go shop bought all the way! All the info has been great though as it does help sort out in your mind which way to go.

Interesting about the Bromptons in the Aygo shemozzle. Our car is even smaller plus we need to get the dog in. So whichever folder(s) we get are going to need an external bike rack.

 

[Cricket]

the small wheels of the folding bikes will garantee good climbing ability - I can't see why you would want crank drive?

I have heard that about the small wheels Trex....will definitely be hub drive.