Mercane Dual Motor Torque Steer

I currently own both the dual motor and single motor Mercane Wide Wheel, I leave one down where I work (200km from here) and one here for the weekend (saves hauling one around and that seemed a valid excuse to try the other when I bought the single wheel first ;-).

Which is better?

It turns not a straight forward question of money vs power (although on the surface it may seem to be).

One of the major differences is that the dual motor has more torque (like double heh) works out to be plenty for hills with my body weight. In fact for all but the steepest hills the single motor works out to be sufficient (meaning that if you're not seeking thrills then it does the job quite well). I mean looking at this trip, I would doubt that the dual wheel would bring much to the table in terms of getting there and back in any significantly shorter time. Interestingly I found that going up the steepest parts of the steeper hills that kicking made a difference on single motor Mercane but curiously it didn't do anything on the dual motor Mercane.

Now part of that is probably that its going almost as fast as I could possibly propel any scooter with my foot, but it feels like I'm putting in substantial energy but that's being absorbed by something. My suspect is the extra weight and the extra resistance provided by having 2 motors instead of 1 (and a very low rolling resistance front wheel).

Weight

The dual with its extra motor and 50% more battery (and extra controller) weighs about 5~6kg more and you do notice this lifting it in and out of the house. I don't think I'd like to lift the dual in and out of the boot of a car, indeed I could barely get the box out of the back of my wagon by myself when I got it home.

Handling

Then there's torque steer, the dual wheel has a substantially observable change in steering reaction under power compared to the free wheeling front wheel. I've noticed that almost nobody (even motorcycle riders) seem to get what's going on in geometery, so lets look at this quickly (and you can read this link if you're interested (which you should be).

Basically the front wheel of a bicycle (scooter, motorbike, whatever) has by its steering geometery built in stability by the same way that castor wheels work on chairs, shopping trolleys you name it. This is clear on a castor wheelsbecause the wheel is clearly behind the bit that spins, but on a bicycle perhaps not so obvious and its done like this:

So on a scooter, the smaller wheel makes the geometery harder to see but its still there.

Now when you have the front wheel pulling, especially when in a corner things get interesting because suddenly there is another force on that wheel pulling the castor around.

Unsurprisingly this makes the steering want to follow the straigh line and you feel that kick in the handlebars quite strongly. I would liken it more to front wheel drive vs rear wheel drive in the pre power steering days, but I guess younger readers just won't even know what that means.

However in a straight line, belting along a flat grassy field (heaps more resistance than the road in case that didn't jump out at you) the dual wheel just hoots along at 21kmh, while the single struggles along. When climbing my drive way the dual wheel power provides some great benefits by not just spinning the back wheel or causing the front to lift ... so its swings and round abouts.

 As it happens I'll be needing that this weekend when I'm doing traffic control at an event up here where I live.