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Road tandem bike conversion?

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Road tandem bike conversion?

Old 07-25-21, 02:45 PM
  #1  
Freerojo
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Road tandem bike conversion?

I have a 96 Cannondale RT2000 and was wondering if something like that could be fitted/converted with a electric motor for pedal assist. Was thinking front wheel.
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Old 07-25-21, 03:01 PM
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kayakindude
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Simple answer is yes. I have a 250 watt front hub on my 2006 Cannondale. The better question is how will you use it? Mine takes the edge of climbing and boosts our speed by just over 2 mph, that's pulling a dog in a BOB trailer.

If you're looking for part time assist that works. If you want more than you need more watts and should consider other options besides the front hub. There are other posters who can explain the different systems.
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Old 07-25-21, 03:37 PM
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Freerojo
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Originally Posted by kayakindude View Post
Simple answer is yes. I have a 250 watt front hub on my 2006 Cannondale. The better question is how will you use it? Mine takes the edge of climbing and boosts our speed by just over 2 mph, that's pulling a dog in a BOB trailer.

If you're looking for part time assist that works. If you want more than you need more watts and should consider other options besides the front hub. There are other posters who can explain the different systems.
it is just for hill climbing assist. Are Dllengers front wheel kits the way to go? The front wheel type kit seems the better options.
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Old 07-25-21, 07:21 PM
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I recently converted our older steel Santana with a front hub motor. If you haven't seen them already, take a look at these threads https://www.bikeforums.net/tandem-cy...s-learned.html and https://www.bikeforums.net/tandem-cy...-electric.html I did the conversion primarily for hill climbing assist: 750W front hub, 36V 24Ah battery. It has helped, but came with more negatives (in my opinion) than the benefits. The system added about 20 lbs to the bike and the hub motor has a fair amount of drag so you have to have some level of assist all the time to overcome the weight and drag (or feel like you are always pedaling with the brakes on). Electric motors are most efficient and generate the lowest wasted heat when spinning fast. When climbing hills, you are generally riding slow which causes the motor to labor and generate potentially damaging heat. If we start a climb at a higher speed the motor will take us up the climb lickity split, but if we start slow, it does offer some assist, but not as much as we would like and it is hard on the motor and battery. I am considering looking into a mid drive conversion. I am coming to conclusion (for us) that a mid drive would reduce the drag, and with the lower gearing, allow the motor to operate more efficiently.

Don't take what I am saying as a strong negative. I do believe that for many, depending on their situations and needs, a hub motor is a very good thing. If you are looking primarily for hill assist, you are probably already laboring on the hills and you may likely find a front hub solution with sufficient performance has some undesired negatives as we did. Take a look at the threads l linked above and, if you are technically inclined, explore the ebikes.ca web site and play with the simulators.

There are others on the forum that have had different experiences and those too are very valid. My message is to do your homework before investing.
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Old 07-26-21, 08:31 AM
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I am not sure if a larger motor results in drag, definitely adds weight. I use Swytch and often ride with the system off and there is no drag, but smaller motor. System weighs around 6 pounds. There are other 250 watt systems that I am sure are comparable, but on a tandem these are minimal systems.
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Old 07-26-21, 01:09 PM
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My understanding of how motors work led me to the purchase of a 750W - 1000W mid-drive system and that was for a single, albeit cargo oriented, e-bike. 250W motors are stronger than the average rider, but when the average rider reaches their limit of exertion they stop and recover. The e-motor burns up. And they do with some frequency. For a tandem, I think a 500W - 1000W motor is essential. Luckily this is what most kits supply. They sell them as 500W to 1000W because at different power levels you get different amounts of motor life. At 1000W the motor life is measured in seconds before permanent damage is done while at 500W the abuse can go on indefinitely. Most 250W motors aren't given any 250W - 500W float. At 250W the motor has only seconds of life at full power before it is destroyed. So at 100W you get all day reliability. 100W is about one person worth of power. It really isn't all that much power. It might seem like it but a motor and battery weigh a fair bit. There is some care that needs to be taken to get the best life out of both. The cost difference between a quality 250W motor and a decent 500W+ system is not big enough to justify buying the undersized motor.

European and Canadian power limits are 250W but that is for single bikes! A tandem needs more and I DOUBT a tandem team is going to be penalized for having a 500W motor in any civilized country. That much power in a front hub is literally a handful. Not recommended, but if you do, a steel fork is recommended and two torque arms. Mid-drives are very well regarded but I think it is interesting that with all the angst in the tandem community about the lack of a good drag brake on the market that many teams are overlooking the fact that a good rear hubmotor with regen makes a pretty spiffy drag brake. A lot more controllable than the Arai drum that was the standard for so many years.
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Old 07-26-21, 04:34 PM
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What ever motor you purchase you need one with a built in thermistor and a controller setup for thermal rollback. Grinn at ebikes.ca orders there motors in with the speedo and the thermistor built in the motors. you can purchase the same motors elsewhere for less money and not have the built in speedo and thermistor.
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Old 12-11-21, 11:50 PM
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JoeShellharbour
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We Have a Cannondale road tandem and have fitted a Dillinger 250w front wheel.
My wife has a ankle injury and only pedals on the one side and chases on the other, the dillinger copes and we can now do the same hils as before injury (most are short hard climbs and so full poer for less than 3 minutes) I also fitted the thumb control so only use power on the hills and take off.
I also am a captain for a group of Vision impared stokers we have 8 cannondales and a bunch of Apllo tandems and one Trek tandem
We fitted a 250w front wheel to the treck for the seriously dissabled stokers and it has the cadence control, I often get placed on the trek with heavy out of condition stokers and find the cadence control a pain as I have to press the raise button 5 times to get max assist for hills then press down 5 times to get it off near the top and also make sure it is off for take off then add assist as we get a roll on .
The thumb control is so much easier as just let go and no assist .. simple.
Also had to contact dillinger as to "how to raise cut in speed" as it was a pain on undulations to hit 50+kmh at the bottom and have to wait for the speed to fall below 19kmh before the motor would kick in .. they obliged and it is now set to cut in at below 35kmh and we sail over the hills after many gear changes as the speed falls like a brick.
Most of the disabled stokers love the trek apart from the fit ex cyclists who like the Cannondales as they flow well on the down hills
regards
Joe from NSW Australia

Last edited by JoeShellharbour; 12-11-21 at 11:52 PM. Reason: spelling
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