The best way to go about powering my Dahon?

[Artstu]

I've bought a bike, now I need to convert it to an e-bike.
It has alloy forks with a 75mm spacing, a Crystalyte will go straight in, but as a direct drive I believe these are at their best at speed on the flat, I want something that will help me up hills at a slow pace.

I'm guessing an 80mm Tongxin could be fitted without too much trouble? would the forks allow that?

I'd really like a 75mm Bafang motor with 28 spoke holes please I'm guessing there is no-way the forks could be opened up to take a 100mm version. Failing that a new set of steel forks spaced at 100mm is a possibility.

Is there anything else I should be looking at? or any thoughts on my desire to have a none-direct drive motor in the belief it will give me the hill-climbing ability I require.

Thanks

Here's the bike

 

[eddieo]

"The best way to go about powering my Dahon?"

steroids? And leave this lovely looking bike alone.......

 

[jerrysimon]

A couple of posts that may help you collect your thoughts

Dan's post http://www.pedelecs.co.uk/forum/electric-bicycles/4682-diy-stage-1-received-bafang-tongxin-kits-photos.html#post59183

My post here

The Tongxin's are REALLY hard to get hold of (if you want to build the wheel yourself), though I now have a contact in China if you want to take the risk and order from him. Also having made a mistake myself with the motor I ordered, I can also advise exactly what motor you need

You also need to ensure you get the right RPM for a 20" wheel.

Not sure if you want to go down the DIY route or buy a kit ?

Alternatively you could order from EWC as they now have 28 hole Tongxin's and may be able to put one in a 20" wheel for you. If they can, I think this is certainly the easiest and fastest route to go down. These are also only 80mm wide spreading the forks 5mm would not be that hard. I think Bafang only do 100m ones as their smallest. EWC now seem to be easy to contact and respond quickly so you will also be able to chat on the phone with them.

If you see Dan's posts he did spread his steel Brompton forks to 100mm.

Alternatively there is always Freedom E who also do kits and may be able to put one in a 20" wheel for you.

Whatever you do your going to need patience. That's a nice looking folder BTW.

PS I notice you say you have alloy forks so you would perhaps need to take advice on spreading those or as you say look at different forks. Most of the suppliers of wider forks will only sell you them in one of their Ekits though.

Regards

Jerry

 

[Herb]

Artstu, You are correct, the crystalyte hub motor is not the best on hills, I have a 209 fitted to my Brompton.

However it is easily available and fits very well in the narrow forks of the Brompton or Dahon.

Also it will also allow the bike to revert back to its native unpowered form as the forks remain standard.

Given the choice again I think I would go for a geared motor. Supply is a problem for the Tongxin

The Bafang is wide at 100mm but if you did manage to fit one - Daniel Weck’s Brompton is the object of my desire, what an Great folding e-Bike you would own.

I am in Somerset if you ever want a test drive a direct drive motor.

Herb

 

[Artstu]

If I didn't have ME I think I would indeed leave well alone eddieo.

Thanks Jerry, I've spent a lot of time reading both yours and Dan's threads, it is indeed a complicated process and nothing is simple and straightforward.

Nothing quite fits the bill at the moment, my wish list is the 75mm geared motor with 28 holes, a simple left-hand thumb switch that holds its own position with another button to release the lever when I don't need power, and a ping battery mounted with the controller on a rear-rack (the bike has rack lugs on the rear stays not shown in that promo picture) not much to ask?

Thanks for the offer Herb, wanting a geared motor if you did it again really answers that question for me thanks I like the idea of reversability so it really has to be either a 75mm motor or new forks and an 80mm Bafang if I can get one, or at a push a 100mm one.

I got a pretty good deal from here however the normally dispatched in 24hrs was a bit wide of the mark at 8 days.

They're now even cheaper from here

Thanks for the replies so far

Stuart

 

[jerrysimon]

Artstu,

My daughter had to defer the last year of her Uni degree (she is back now) as she developed ME after several major illnesses and quite scary stays in hospital. She had an official diagnosis (at least it is a recognised condition now) and in fact went on full incapacity benefit because of the care my wife and I had to provide.

Although controversial we bit the bullet and sent her on the "Lightening Process". For her it seemed to work though its not for everyone.

Recovery seems to be more promising for younger people who have not had the condition too long.

Regards

Jerry

 

[flecc]

Bearing in mind how cheap a new rim is, a 28 spoke hub isn't vital. In fact a 36 spoke setup is preferable when a
high torque motor will be transmitting it's power out through the spokes to the rim and tyre.
.

 

[jerrysimon]

Flecc raises a good point.

I was thinking about a Brompton 16" wheel which are a little hard to source with 36 hole rims.

The Dahon 20" rim may be more readily available with 36 holes.

Regards

Jerry

 

[Artstu]

Where do you get a Bafang motor from?

Ok thanks guys

So could I put an 80mm wide Bafang hub in my 75mm alloy forks? and where can I buy one from?

Thanks

as an aside there is some very dubious wheel building on the back wheel, the hole in the rim limits the angle at which the nipple exits it, so the spoke has a kink in it where it exits the nipple, pretty poor considering Dahon must make thousands of bikes with 20" rims.

 

[jerrysimon]

Sorry I am pretty sure the slimmest Bafang is 100mm wide.

Regards

Jerry

 

[Artstu]

Oh OK thanks Jerry, I've been to that many web pages recently I'm getting confused

 

[jerrysimon]

Oh OK thanks Jerry, I've been to that many web pages recently I'm getting confused

Trust me after a few weeks this stuff will have your head spinning

Unless you want to have a go at sourcing a motor and building it into a wheel yourself, why don't you try phoning EWC and have a chat with them. I have spoken to them and the new operation seems much better now.

Also Kinetics in Scotland do conversions as well I think.

Regards

Jerry

 

[daniel.weck]

Hello !

It's a Dahon Mu, right ? What model is it exactly ? 3-speed hub gears, etc. ?

Back to the topic: I'm not sure about widening alloy forks...it sure is perfectly safe with steel (when done properly), but with aluminium I'd recommend double-checking. There's a guy on the German forum who replaced the alloy fork on his Dahon (a different model, not Curve or Mu, I can't remember now) with a steel one, but it has been a painful process (finding parts, spacers, washers, tools, etc. and even grinding the tube !).

You should verify that your forks are actually not steel, using a magnet (who knows) Oh, and what is the factory spacing between the fork dropouts on your bike ? Maybe it's wide-enough already.

The Tongxin 80mm is the smallest you can get, the Bafang 100mm is a great choice but the fork needs working on with caution. I have seen the BionX kit on a few Dahon folding bikes, it's a thin motor with top-notch electronics (expensive though). BionX electric bike motor systems

Good luck, let us know how it goes.
Cheers, Dan

 

[daniel.weck]

 

[rooel]

If the OP had not already bought his Dahon I would recommend a look at this thread

http://www.pedelecs.co.uk/forum/electric-bicycles/2506-24v-alien-installation-2.html?highlight=Dahon+Speed+TR

which discusses the advantages of all steel bikes for the fitting of a 100mm motor. There is no problem in widening the steel forks on the Dahon Speed TR or the Dahon D7.

I have widened forks on both and fitted the 24 volt Alien kit with very good results, and I think the steel frame gives a less jerky ride as well. It does not seem to be much heavier than the aluminium frames, perhaps because the latter, being more brittle, have to be built with thicker sections.

Here is one of my Speed TRs

 

[Artstu]

Hello Dan

Yes it's an Mu XL Sport with an 8-speed Nexus hub

Yes the forks are triple butted aluminium, a change of forks looks to be on the cards then to accommodate the Bafang motor, they're 75mm wide at the drop-outs.

That's interesting, that blue Dahon folds the opposite way to mine, and my stem and bars end up on the outside when folded.

It looks like it isn't going to be as simple as I thought it was going to be

Cheers

Stuart

 

[Artstu]

Thanks rooel, I wish I'd known that earlier now

I guess I could buy one of these D7

and then keep the Mu as a beautiful ornament until they find a cure for my ME, and it's really not as daft as it sounds.

 

[rooel]

"I guess I could buy one of these D7"

Yes, Artstu, I bought my D7 from J E James too, but at only £220 earlier this year, thanks I think to it being the previous year's model. Perhaps there will be some more bargains there early in 2010.

 

[Artstu]

A bit of patience should hopefully reap the reward of getting one cheaper. I'll keep my eye on them.

I know they have dropped the price of the Mu XL sport by £10 since I first looked. Worth having a D7 for the price of an electric motor I think.