Pedal Assist for Tadpole Trike


New Member
I'm a seventy year-old guy with a heart condition who would like to have some assistance in getting up hills and/or riding longer distances on my trike. I have an HP Velotechnik Scorpion tadpole trike with 20 inch wheels. I have a Schlumpf Mountain Drive upfront with a Shimano derailleur in the rear along with a DD 3 internal hub.

I'm not interested in a mid drive set up nor a rear hub mounted motor as I would like to keep the gear set up that I currently have while using the assist only occasionally as I need it.

So, what I am hoping to do is put two front wheel hub motors on this tadpole trike with either separate controllers and/or batteries for the two wheels. I know this may seem a bit crazy, but I just want to know if it's even possible and how I might proceed to get this to work for me. Anyone tried it? What are the engineering challenges and application issues

Thanks so much,



Well-Known Member
What are the engineering challenges and application issues

What you are proposing is certainly possible, but there are a few problems to overcome. For one, if the motors aren't properly matched with regard to RPM you will always have a steering issue. Not to toss a wet blanket on your requirement but a mid-drive makes a lot more sense.

Court J.

PS....the 20" wheels may be an issue for lacing the wheel.


Well-Known Member
You might consider this instead as it will give you the internal hub shifting you now have as well as a decent amount of power.

You will want to switch to a speed drive though after putting the motor on there :). I use a high speed drive on my 700c wheel bike and it works great for that purpose as you tend to use higher gears than normal to pedal along with the power the motor provides.

Ann M.

Well-Known Member
Although it's a bit cumbersome, it is doable, @Earl. We've used dual Golden Motor systems that are wired to operate with two controllers (they're internal in the motors) with one or two batteries. Both are operated with one console, throttle and if you want to, add the pedal assist & regen options. Go take a look at the videos and parts at Gary Solas has done a variety of dual motor setups, has parts already designed for dual motors (including motors already laced in 20" rims) and is a good resource for info. Other hub motor brands could also work, just not sure which have already done the controller & wiring harness configuration already.