Tandems..?

[wissy]

Just went for a little stroll across the bridge to mainland and through University gardens and seems there is a tandem festival on in the area.. Heaps of them camping in a field... Got me thinking and wondering how tandem pedelecs work? Are there two motors??? If there are two motors giving assistance separately at 15mph will this make the tandem move at speeds close to 30mph??? (I did get 23% in physics decades ago) .. there must be a way the rear person speeds up the bike without going faster that the person in front.. If you get what i mean?? (Not overtaking obviously!).....

(Completely sober......soz)

 

[Aushiker]

The ones I have read about such as the tandem recumbent in the photo have one motor. I assume the main rider, not sure what they are called in tandem language do the controlling.

Andrew

 

[Deleted member 4366]

You could have as many motors as you want. It would go pretty well with two cranl-drives and two hub-motors. Maybe my next project.

Most electric tandems that I've seen, just had one hub-motor, normally a strong one like Ezee or Bafang BPM with the controls at the front. It's not fair really that the front guy does the steering braking and works the motor, while the other guy just pedals.

If you put two 15 mph motors in a Tandem, it would still only do 15mph since they go at the same speed, but you could climb steeper hills.

 

[cwah]

You could have as many motors as you want. It would go pretty well with two cranl-drives and two hub-motors. Maybe my next project.

Most electric tandems that I've seen, just had one hub-motor, normally a strong one like Ezee or Bafang BPM with the controls at the front. It's not fair really that the front guy does the steering braking and works the motor, while the other guy just pedals.

If you put two 15 mph motors in a Tandem, it would still only do 15mph since they go at the same speed, but you could climb steeper hills.

Are you really going to have something like 2 cranks and 2 hub motors? lol

How was your bike with 2 motors and a crank drive? Did it have super crazy efficiency?

 

[Deleted member 4366]

How was your bike with 2 motors and a crank drive? Did it have super crazy efficiency?

It had crazy acceleration something like 150Nm of torque. Even a 131kw Honda Fireblade only has 112Nm. It would have been great to be alongside one at the traffic lights to see the riders face when he's beaten away by a bicycle.

 

[cwah]

I'm thinking of getting a dual xiondga. Dual drive would also allow me to have system redundancy in case 1 motor breaks.

Since my bpm broke I'm pedaling without motor since 2 weeks
My bpm replacement has been struck in customs for 1 week now

 

[Deleted member 4366]

I don't see any advantage og two Xiongdas. Their advantage is high torque from a small motor. If you want two motors, two 328 rpm Q100s are pretty good.

 

[flecc]

BikeTec make the Panansonic powered Flyer Tandem, the motor unit on the front crank set.

 

[john h]

The ones I have read about such as the tandem recumbent in the photo have one motor. I assume the main rider, not sure what they are called in tandem language do the controlling.

Andrew

front person is called the captain the rear one is called the stoker

 

[cwah]

I don't see any advantage og two Xiongdas. Their advantage is high torque from a small motor. If you want two motors, two 328 rpm Q100s are pretty good.

Why 2 xiondga wouldn't be better than 2 q100?

It would have better efficiency and torque right?

 

[Deleted member 4366]

It'll have more torque, but I don't know about efficiency. It doesn't seem to be any more efficient than any other hub-motor.

 

[Aushiker]

front person is called the captain the rear one is called the stoker

Ahh thanks.

Andrew

 

[cwah]

It'll have more torque, but I don't know about efficiency. It doesn't seem to be any more efficient than any other hub-motor.

Ok if it's only more, and nothing less...

Why should I get 2 q100s instead?

 

[Deleted member 4366]

They're simple, light and quite powerful when you have two. It's not so easy to go slow though. I think that if you had two Xiongdas, they'd be in high gear all the time anyway, which would be the same as two Q100.

With two Xiongdas, you'd need two throttles, two LCD displays and two three position switches on the handlebars. It would be a bit cluttered. You can use the Q100s with KU63s, so no LCDs.

 

[trex]

it would be a lot easier to use one xiongda plus one BBS01, both run with a single 48V bottle battery. Wiring is easy, weight distrubution is like in a normal bike, plenty of stealth, both motor only need one throttle. I reckon you could pull wheelies with this configuration. Each motor has EN15194, I wonder if you put both in the same bike, would the bike pass EN15194 too?

 

[jackhandy]

Twice!

 

[cwah]

They're simple, light and quite powerful when you have two. It's not so easy to go slow though. I think that if you had two Xiongdas, they'd be in high gear all the time anyway, which would be the same as two Q100.

With two Xiongdas, you'd need two throttles, two LCD displays and two three position switches on the handlebars. It would be a bit cluttered. You can use the Q100s with KU63s, so no LCDs.

Yeah but don't forget where I live there is a red light every 300meter. What uses the most power in my journeys are not the speed, it's the acceleration.

That's why acceleration is so important to me.

And why can't I use 2 xiondga controller wired to a unique throttle?

 

[Deleted member 4366]

And why can't I use 2 xiondga controller wired to a unique throttle?

Those that tried that found that it doesn't always work. You need to make a double throttle or buffer the throttle signals. On my tripple motor one, I used the CA to buffer the signal.

 

[Martin@e-bikeshop]

Anyone scrolling this thread should now also know that we have an exclusive Bosch powered tandem eBike!

Details here: Bosch Tandem Electric Bike

Regards
Martin