kentpaul

So I bought a run down old Dahon Espresso D21 about 2 years ago on Ebay for £120/ $160. It was fine but I decided to upgrade it with power.

I used a 1000w Voilamart rear wheel kit with LCD display off amazon and a white battery off ebay.

It will get up to 30mph on the road and 18-20mph across rough ground. I also put some front shocks in. At those speeds I feel it is at the limit of what the other parts like brakes are really good for, in fact I dont like going over 23/24mph on the road.

I am pretty incompetent with mechanics so I had to buy various tools and it probably took me 7 or 8 hours in total with things like lining up cables being a real pain for me. The local bike shop said they would have fitted everything and done a service for maybe £200...

I also had to do the service on the bike, so I would have been better off buying a better donor bike in the first place. Betweeen the front shocks and other parts I am probably into the donor bike for £350 but I could buy a used top end full suspension bike on ebayfor £450-550.

Front shocks:
One way or another the shocks I bought have a tube that tapers from 1 1/8" to 1 1/5" at the base, ie 28.5mm to 30mm. This caused a problem as the Dahon crown race at 28.5mm sat a few millimeters above the top of the forks. I ended up ordering a split ring off ebay from China that bridges the few mm gap. I tried to get a photo of it, you can just about see the split ring in the photo.

I replaced the old gear shifters and the front derailleur.

I put in a heavy kick stand from Decathlon. I think the two legged ones are better for this weight of bike though, it feels like it could fall over easily with the battery on it. The bike weight is very back ended and it has tipped over more than once now.

I mounted the cables, the controller with cable ties.

The battery connectors and the controller power cables didnt match. So I had to strip down the battery cable and in the end used a 32a junction box designed for your house's electrical circuit. I wrapped most of the connectors in tape and put it all inside two bags that I taped up and the open end of the bag it is at the lower end of the controller bag.

I need to figure out what to do about lights and a lock now. There is a power cable for lights in the controller box.

I could not get the crank arm off so gave up on fitting the pedal assist, this is a problem in the UK as you are supposed to have a PAS system to cap power output at 250w on the road...

So it just drives throttle on/ off which makes it more like a motorbike. Fitting pedal asset would be beneficial and you can change the settings in the LCD anyway.

The battery is mounted on two screw clamp style bottle mounts assembled in a T-shape, they were from Decathlon, so was the kick stand.

Things I dont like so much:

I cant straddle the bike upright, so need to stop by the kerb or tilt the bike to stand, Im 5'9/ 175cm tall. At 6' or 6'1 this would not be an issue though.

Hitting bumps in the road at 25mph is not the same as 18mph or so. I think this level of power better suits a full suspension bike with bigger tyres and hydraulic brakes and 27.5" tyres.

My eyes water at speed, although it was only 4 degrees today and I could have taken my ski mask, just used regular sunglasses.

At over 20mph the tyres throw a lot of dirt up.

In the end you dont put much effort in pedalling without pedal assist and part of the reason I cycle is fitness, so its a bit counterproductive, but I can still use my 6KU fixie bike for commuting some days. Also the reverse induction of the motor means you cant really use the bike without power. There is just too much drag. I think there is 50 miles or so charge on the road with that battery though, but you would probably take the charger and charge it at lunch if you went out all day.

The folding frame makes it awkward to mount the controller and battery, it would be better to have that weight lower, but the full suspension bikes have the same issue as well.

https://imgur.com/a/lWzYYKE

Geepig

A great job, and now not only do you have a unique bike but a whole bunch of new experiences and expertise. It is always worth remembering that even if you had shelled out the extra to buy a bike with more kit on it, that does not mean you could have saved money as all that high end stuff usually needs servicing and some replacement first.

kentpaul

yes good point these older bikes are faily low maintenance vs the high spec new ones.

Barchettaman

Interesting project.

I electrified my Espresso with a front wheel Swytch Kit, it works pretty well.

::edit:: I see you noticed my thread!

onionsmasher

looking gnarly!!

I also have a dahon espresso (these beasts are one of a kind) and in the middle of the process of accumulating the parts needed to convert it into drop bar bike.
in the meantime, it will remain attached to the trainer waiting for the rainy season here to pass.

bikebikebike

Interesting about the front fork. I have a Dahon Matrix, that took a 1- 1/8 fork without the broughhaha, but will keep that in mind for my next big foldy project.
Good looking, but hard bike to mount anything but a tail battery on, and that is more tsuris when trying to secure and to ballance

kentpaul

if the battery was on a rear rack there would be so much weight at the back

i think i have bearing problems with the rear wheel but havent tried to open the hub yet. it doesnt make sound spinning but does with a body weight on it.maybe something simple like a little grit leaked in. the rear hub got submerged before in the woods.

Doc_Wui

I am glad you posted a picture, because I thought all Dahons were 16"-20" and I wondered how one could do 30 mph, Whew.

bikebikebike

Sealing can be an issue. The ebikes.ca sealing discussion is on cooling fluids inside,
but has the same challenges,esp since they are in Vancouver, where it has been known to rain.
There are lots of teardown vids , if you want to look first and haven't done one before.
Bearings shouldn't be a challenge , but clearance between the stator and rotor are often tight and can get gunked.
Weight and balance are a challenge with ebikes and and most mods bump into that.
Handling and balance get affected., which is why fancy ones go to mid drive with downtube bat when raw power isn't the main goal.

kentpaul

I have done about 2000 miles on this now mostly across London commuting but some offroad

All I would say is the brakes need to be good if you are going over 20mph in order to stop
The rear wheel Voilamart give you is not puncture resistant, which is pretty crap, I have had about 5 new inner tubes in it so far.
The centre of the read wheel is worn flat as well from braking.
I had to add a third bottle holder as two were not enough to secure the battery.

Sardines

Have you checked where the tubes are leaking? Would give you an idea if it's the spokes that are poking through because of bad rim tape or maybe a hidden stuck sharp object in the tire?
I have to say an E-assist on rim brakes is probably pushing the limits of the brake a bit too far. Harder compounds will probably squeak and wear out the rim brake space. I would not have any assisted bike be rim braked for safety reasons, even if it's for commuting.

Barchettaman

My Espresso is also electric assist but at 250w max power with a Swytch kit.

I upgraded the brakes to Magura hydraulic rim calipers. It stops well.

Numerozero

Same here. I upgraded to Magura HS33's when I installed a TongSheng TSDZ2 motor on my Downtube 8FH.

Damnage

I have an espresso too and went w/ a 48v 1000W rear hub motor kit as well. Did you have to file down your dropouts at all to get it to fit? Right now I have a gap where it should fit into the dropouts but will have to file it down to get it to fit it seems.