Converting a tandem trike

[David Stanbridge]

Hello, I'm new to world of ebikes, and this looks like the best place to get unbiased advise.

I'm hoping to put an electric motor on this http://www.huka.nl/assets/Uploads/producten/downloadables/Copilot3/Specs/Specs-Copilot-3-26-EN.pdf

I don't need it to go fast, just help starting off and, surprise surprise... hills.

My research so far is leading me to a rear hub motor, with a throttle control.

Great forum BTW

Thanks

Dave

 

[trex]

you may lose the pedal brakes.

 

[Deleted member 4366]

Do you already have it? I don't want to be a party pooper, but that looks very dangerous. Just about every one I know with a trike has toppled it at sometime. With two people sitting upright, the high up centre of gravity would make it very unstable at anything over about 10 mph. The problem starts when you hit a bump with one of the front wheels. Without suspension, you and your passenger will be knocked sideways and the pendelum effect will take you the rest of the way.

Regarding the ectrification. That won't be easy unless you're a good mechanic. It can be done, but not with any standard kit unless you can fit a crank-drive somewhere. We'd need more information on the bottom bracket dimensions to be sure. You'd have to lose most of that fancy chainguard.

You might be able to fit a Cyclone kit on the main frame tube.

http://www.eclipsebikes.com/motor-kits-cyclone-chainwheel-motor-c-73_117.html

 

[David Stanbridge]

Yes I already have it, I've been cycling it all summer with my son, we haven't got close to toppling it yet. We don't go fast, but the hills are a killer.

 

[trex]

rear BPM hub motor is best for it.

 

[David Stanbridge]

How do get the bottom bracket measurement?

These are the front and rear bottom brackets, I'm guessing the front one would be easiest.

 

[David Stanbridge]

Who sells BPM hub motors?

 

[trex]

tandems are not suitable for crank drives because the rear bottom bracket has two chains and your crank drive has only one.
For rear hub kits:
You can get an oxydrive, d8veh is your guru.
If you want a more powerful kit, woosh sell BPM kits. Nealh has one.
http://wooshbikes.co.uk/?hubkits

 

[David Stanbridge]

Could a crank drive be fitted to the the front bottom bracket, it seems to be a fairly standard bottom bracket.

 

[trex]

yes, that is possible.
I forgot that your front chain ring is on the right.

 

[Deleted member 4366]

In the photos, it looks a bit on the wide side. You measure from one end of the tube to the other. The standard is 68mm. Some MTBs have 73mm, which is still just about OK for standard crank-drive kits. Any more than that, and you need something special. There's plenty of ways you can fit a motor, but the amount of DIY can be a lot.

 

[David Stanbridge]

It is 68mm, but I have other reservations about where the motor would be placed.

 

[Nealh]

As I see it the best option is a crank drive that way you keep your 7spd rear hub and the pedal brake as trikes are req'd to have three.
The rear crank has the drive chain as well as the double chain ring so can't be put there, front is the place for crank drive like BBS01. A rear BPM or CST would mean the loss of the pedal brake and the 7 spd hub, though they both give very good torque for hill climbing.
Also the battery what type and where to fit, I think with a BBS the new slimmer 08 battery would/ may be best sat in the middle step in, this ideally would keep the centre of gravity low and in the middle.

 

[David Stanbridge]

The front crank is bolted on rather than welded, would that be a problem?

 

[David Stanbridge]

I've just looked at the Huka website and they offer pedal assist as an option, they look like rear hub motors with batteries on rear rack.
http://www.huka.nl/products/begeleid-fietsen/copilot-3
They also have derailliers.

 

[Nealh]

The front crank is bolted on rather than welded, would that be a problem?

Probably make fitting a BBS easier as you can unbolt fit the crankdrive/motor and chan ring then offer it backup to rebolt on, that way you may be able to keep the nice chain guard.

 

[David Stanbridge]

Okay, so where to place the motor?
There isn't much room in front of the crank, as the front section of the frame is removable, it joins just in front of the crank.

 

[trex]

the motor will hang from the bottom bracket and be quite close to the ground.

 

[David Stanbridge]

Like this?

http://i01.i.aliimg.com/photo/v0/60147134937_4/electric_bike_bafang_crank_motor_KCMTB019_.jpg

Can all crank drives be fitted this close?

 

[David Stanbridge]

I think I've just answered my own question.

http://www.eclipsebikes.com/bafang-8fun-bbs01-drive-250w-motor-p-1102.html

This looks like it could be the best and simplest option.