Budget dahon d3 curve conversion...

[Tsakis]

Building my new bike the last 2 months, I am taliking about pedelecs, ebikes and bikes all the time.. AS a result my Girlfriend started to like the idea of her driving a bike so she decided on grabbing a used Dahon D3 curve that I found on a bargain...

So, being a nice boyfriend and also one who wanted to test his DIY skills (not that high I must tell) I decided to get her the electric conversion as a gift. Giiven my current build though, my budget is EXTREAMELY limited.

The D3 is a hefty bike to convert, looks like a brompton in a lot of aspects, low weight, hub gears, 16in wheels... I am concerened about the fork size and if I will be able to find a motor to fit, I am currently waiting for an answer from dahon for the exact fork dropout..
Because of the light weight of the bike and my GF beeing roughly 48kgs (!) and not so strong, I want to keep the weight low to ensure the bikes portability and preformance with not so expencive equipment..

Because I am on a budget I frist thought of BMS battery, eventhough I am dissapointed by their service...

I was thinging about this combination:

motor:
Q100 24V350W Front Driving E-Bike Kit - BMSBATTERY

Battery:
24V8Ah Li-Ion EBike Battery Pack - BMSBATTERY

So I have the following questions:

1) What do you think about my selections? Can you think of anything else for this bike given my tight budget?

2) Proveded I ll find a motor to fit the fork, can this fork handle the pressure?

3)this motor is a cute one right? Those are geared, am I correct? Anyone ever tried one?

4) What preformance should I expect from this combination for a 48kg rider?

5) Is it hard to fit an on of swich for the battery? I was hopping to find a nice waterproof bag to put the battery and the controller on do you have anything tested on your mind that would look nice on this bike?

Thanks in advance...

 

[Tsakis]

It appears that it will be more difficult Than I thought... I need an 80mm front hub motor...

 

[jerrysimon]

Yep unless you are prepared to spread the forks wider.

I think there is a 80mm cute motor but the only other alternative if you don't want to spread the forks wide is the 260RPM 80mm Tongxin motor.

Follow the build threads and relative info on this link if you are interested.

Regards

Jerry

 

[Tsakis]

Where can I find the tongxin motor and how much it costs? The cute can be aquired from BMS battery right?

 

[flecc]

Isn't there an 80 mm Suzhou Bafang motor now Jerry?

 

[jerrysimon]

Flecc I am not sure as I haven't really followed Suzhou developments. Certainly that would be a good alternative to the very hard to source Tongxins.

Tsakis Tongxins are very hard to source except through full kits.

I am sure I saw a post the other day with a reseller who said he was working on his web site and may be stocking a few Tongxin motors though.

Regards

Jerry

 

[jerrysimon]

This one in the first link below on the BMS site states it is 83mm wide (click the data sheet tab for details).

It is s difficult if you can't see a complete picture of both sides of the motor as sometimes you can end up with a motor that has a roller brake fitting, as I know all too well from personal experience

Fortuantely I was able to modify mine to fit in the Brompton.

Q85 36V 250W Front Driving V-Brake Hub Motor - BMSBATTERY

Although the 36v states it is out of stock it says it has 6 of the 24v ones, link below. I am not sure how well a 24v one would perform, although of course it will draw more current at 24v for the same power as a 36v.

http://www.bmsbattery.com/front-driving/355-250w350w-q-85100sx-motor-e-bike-kit.html

I think both of those are Cute motors not Bafang.

Regards

Jerry

 

[Tsakis]

Well I pm'd the reseller to find out if he can provide me a 16in wheel with a tongxin on it...

Interesting... They still have some motors but the give it seperately... I ll mail them to ask if they can fit it on a 16in wheel and send it with the other parts needed for the conversion...

I think the d3 fork is alloy though, you don't think I ll have a problem streching it just 3mm, right? ( I don't even ask about strching it 20mm to fit a 100mm motor... :-s)

 

[jerrysimon]

Well I pm'd the reseller to find out if he can provide me a 16in wheel with a tongxin on it...

Which reseller ?

Regards

Jerry

 

[Tsakis]

I am sure I saw a post the other day with a reseller who said he was working on his web site and may be stocking a few Tongxin motors though.

This one!

The fork of your brompton is steel, right?

 

[jerrysimon]

Yes it is steel. To check your D3 simply stick a magnet on it which is the simplest test. I am sure the forks would spread a few mm no problem.

The Tongxin (180W) is not as powerfull as a Cute or Bafang and you could probably get away without a torque bar but you would need to ensure it is fitted properly i.e. washers and nuts sit flush again the fork sides.

Is that sellers web site up and running yet ?

Regards

Jerry

 

[Tsakis]

I don't know, I just sent him a PM.. I guess a cute 250w running on 24v will also be ok without torque arm... How safe is spreading the forks 5mm when alloy?

 

[jerrysimon]

I cannot see a problem spreading them 5mm.

Regards

Jerry

 

[Tsakis]

Nice to hear that... I am concerned whether I will be able to coplete the conversion or not... The d3 comes in a very good price and i have to buy it quickly before someone else does, but I will decide against it if it cannot be turned to electric.. We want to ride together and given the exreamly hilly area We live it would be hard without an ebike..

Will 24v be enough to getting my 48kg girlfriend up the hills?

What kind of performance should I expect from the 24v 250w x85 cute motor?


Generic question:
I heard that volts has to do more with top speed and amps with acceleration. Given the same watt rating for two bikes/ kits with different wattage does this means that the 24v one will accelerate faster? (assuming a higher amp controller to accommodate the lower voltage?)