About to order Pie Which one?

[OzGeeksGarage]

Hi,

I'm ready to order a Pie, I have a 20" rim Trike just arrived and unpacked and wish to put the Pie on the front wheel. A small 34 tooth crank drives a 7 speed cassette driven axel that drives each rear wheel by a 1:1 chan drive & sprockets on the inside of the wheels with each ratcheting to avoid the need for a differential I suspect.

This Trike is to enable me to have some mobility to and from the shops with some shopping in the boot via local flattish backstreets for a few years as Advanced Glaucoma has rendered me Legally Blind by tunnel vision and unable to drive. I'm an Electrician by trade with Electronic automation engineering experience so this is the start of a new project for me. I live in Queensland Australia so am going to try and keep as close to the laws as I can with this. I just want to confirm a few things before ordering this weekend.

So it looks like I need the SmartPie Kit and it seems it needs the MP III USB cable to program it?

Next question is PAS, I'm unsure whether I want it or not or need it to comply with Laws, regardless, I was planning on ordering it, I'm assuming I can just not fit it or disable it by the software if I desire or is the PAS Smart Pie a different pie to Non-PAS Smart Pie? Or would it get confused due to the 7 speed gears between it and the wheels? I'm going to assume because the front wheels & back wheels are the same diameter it's not going to care if it's not connected to the actually driven wheel.

And yes I have crazily considered twin Pies for the rear wheels instead, it looks doable, twin 6 speed cassettes could be interesting for lower range reduction,  LOL? Though I don't know if it's possible to get a Cassette with Left handed opposite rotation/ratchet drive

 Thanks for reading and any help on this.

[Bikemad]

Hi andto the forum.

I built a four wheeled pedal car (many years ago) which had a very similar drive train to your trike. The twin freewheels are nowhere near as good as a differential at low speeds, as they only allow power to be applied to the slowest wheel, which unfortunately makes it very difficult to pedal away on tight turns as the inside wheel barely moves.

We had to race the above pedal car on a clockwise track, and I had to remove the chain driving the right hand wheel so we could accelerate out of the tight bends, with both chains driving it was like trying to pull away in top gear.

Although, your trike should be quite low geared with 20" wheels, and the rear wheels will probably be a lot closer together as well.

The pedelec device adjusts the amount of power relative to the pedal speed, so if you use you lowest gear you will get the highest amount of assistance from the motor, regardless of the wheel size.

Although the motors are the same, I understand from GM that if you order a kit with pedelec, the motor harness comes complete with the three pin connector for the sensor to plug in to. If you order a kit without pedelec, the pedelec wires coming from the motor harness are simply left unterminated.

If your trike is pretty stiff to pedal, you are likely to be using motor assistance most of the time, in which case it might be worth choosing a Magic Pie rather than a Smart Pie, as it will provide a much better braking effect, and more usable torque.

The four main disadvantages of the Magic Pie (apart from the higher cost) compared to the Smart Pie are:

• The 20" cast MPIII is much heavier than a Smart Pie (But the extra weight should help to provide more grip).
• The MPIII has a lot more dynamic drag caused by the greater number of magnets, and the much larger motor diameter.
• The outside edge of the cast rim is not ideal for use with conventional "V" brakes (but it should be perfect for use with a disc brake setup).
• Standard 20" bicycle tyres do not fit the cast rim very well.

Regarding the law, if you are restricted to 200 Watts maximum power, it will obviously be better than nothing, but I think you will want to use a bit more power than that.

Alan
 
P.S. I forgot to say that the programming cable is the same for both the Smart Pie and the MPIII.