Monday, November 24, 2008

The right electric motor


Today I finished my Surly Big Dummy build up. I'll post about that in more detail soon (with pictures). Before that, I'd been riding a Yuba Mundo recently, with one of the new BMC V2 motors. That V2 motor has a top speed of about 28mph at 36V, and higher still at 48V. It is very fast. But, the Yuba is geared such that its fastest gear only allows pedaling at about 17 mph. This means that if I had the throttle going pedal to the metal, my pedaling was useless - the bike was going too fast, and it was like a motorcycle. I was starting to get used to not pedaling if I wanted to go fast.

The Big Dummy is built with an eZee hub motor in front, and a Nuvinci continuous variable transmission in the rear for pedaling (by the way, we sell these built into wheels - someday we'll list them on our website). The eZee has a top speed around 21mph at 36 volts, and the way I have the Nuvinci set up, I can pedal the bike up to around 24-25 mph.

I noticed a difference right away. I realized how much I really missed pedaling the bike on the Yuba. It is funny - when I visited China a while back, lots of people had electric bikes, but almost nobody pedaled one. But, I (re)discovered that I like pedaling.

This made me decide - I don't want an electric bike that can go 35 mph, except on the rare occasion when I have to get somewhere in a hurry. I enjoy the more leisure pace of biking. A 20 mph hub motor provides a great balance of assistance, without dominating over the rider's pedaling effort. It is about the right amount of power to provide a balanced human-hybrid electric drive that gives exercise while getting me there in style. I might on occasion hop on the faster electric bikes to zip around (and to zoom by the little motor scooters that can't keep up - seriously, the V2-S BMC is FAST), but for the most part I'm going to enjoy bicycling pace, which is slower, more relaxing, and provides more exercise.

1 comment:

Kwikfile said...

Morgan,

Just watched the video - it mention no fixed gear ratios , but there must be an equivalent min/max compared to a traditional geared bike. Just curious about hill climbing and conversely top speeds. Looks very clean and smooth. No more getting stuck at a light in "High" gear by a surprise Red light. Love to hear how actual riding goes - looks awesome.

Carl