Electric Motor's in the Pro Peloton

[morrisond]

I know this is very unlikely and I assume someone has thought about this before - however what about this concept?

They've been searching for electric motors in the BB's - What about Electric Powered RD Pulley's?

On Di2/EPS bikes you have wires running directly from the battery to the RD - embed the Wires in the Derailleur Cage and put tiny motors in the Pulleys - even better if the pulley's are oversized!

I have no clue how much torque could be added but even a 20-50 watt boost for 10 minutes would be something.

Highly unlikely but theoretically possible and without taking apart the RD almost impossible to find.

Use the mysterious button on top of the Di2 Shifters to turn the motor off and on.

[743power]

A motor driven pulley would most likely cause the chain to skip off the back of the cassette unless it was turning at a very low rpm. Regardless I've never seen a motor that would even come close to fitting in the form factor of the hub of a derailleur pulley, without sticking out a cm or more and at that size, it would probably just cause more drag then anything.

[morrisond]

I was kind of joking with the whole concept - but yes that does make sense about the chain - however you would have an awful lot of watts (4-10x) keeping it on under tension - it would be more of an assist.

Is there nothing from the RC world that small?

[petepeterson]

http://cyclingtips.com.au/2015/07/hidden-motor-demonstration-with-greg-lemond/

https://soundcloud.com/cyclingtips-blogg/greg-lemond-on-mechanical-doping-and-the-potential-use-of-motors-in-the-tour-de-france

[HammerTime2]

So to some it up, a competitive computer should:
1) Dope to the gills
2) Use a motor with 250W output
3) Digitally dope their files
And there you have it. It's not a choice of which one, it's all of the above.

[HillRPete]

Is there nothing from the RC world that small?

There are small powerful motors, but they run quite hot and operate at higher RPM. I suspect they would not be very effective at the low RPM needed to drive the chain directly. Also, as others have pointed out, they are still not as small as a pulley (I've seen strong onces that are about 2 pulleys wide), and with the RD's fore/aft movement to account for sprocket size, you'd need to lock it to a gear to prevent skipping when actually transmitting torque.

I'd say a somewhat oversized rear hub has more potential to house a motor, but there's still the issue of low RPM, because unlike BB assist motors, there is no transmission.

Now, putting a motor into an oversized chainstay, and drive via a modded disc caliper and disc, that would be something to look into (says my electrical engineering self).